An Infinite Number of Cats on Keyboards

Amateur Radio: My First Net Check-In

2012-01-24T20:16:00.001-08:00

Tonight I managed to successfully check into the 2m net for the Nevada County Amateur Radio Club. Originally I just intended to listen in and check in on the later 10m net. I figured I had a better chance of getting in to that, since VHF hasn't worked well for me previously.

So I tried to monitor the 2m net from inside next to my HF rig. First with my Yaesu FT-250R handie-talkie and its rubber duck antenna, then with my old Kenwood TS-700A and a ground plane antenna. The Kenwood's S-meter was seeing a signal, but I wasn't getting any audio.

So I disconnected the ground plane from the Kenwood, hunted up a short length of decent coax, and a broom handle. Yes, an actual broom handle. Or a mop, it's pretty universal.

Two large broccoli-bunch rubber bands later, I had the ground plane antenna mounted on the broom handle and with a nice little BNC adapter I had that hooked up to my Yaesu HT. Then I went out in the driveway and walked around.

How I Did It. 40m dipole strung from tree to mast on roof, 2m Yagi 20' above garage roof, two Kenwood base stations. First net check in: 5W HT with a ground plane on a broom stick handheld in the driveway.

Now, I've tried to do this before to get in to the Grass Valley repeater, but it hasn't worked. In the past I had always looked for the strongest signal on the S-meter from the repeater while someone is talking. This time I figured I was just going to listen, so I went looking for the lowest noise level. I was getting the signal pretty well, with some cutting out here and there as I walked around. Once I found a spot with a pretty good signal, I'd walk around and see how much I could cut out the noise.

After a bit, as the check-ins went on, I had narrowed it down to two spots. I tried out each and decided it was pretty much even, so I stayed at the one closest to the house, figuring I'd be a bit less likely to kick a skunk where I had a bit of light. The HT and broomstick antenna was a two-handed affair, so there was no room left for a flashlight (besides, I was hoping there might be some aurora showing in the north tonight.)

I listened in on the check-ins, wondering why I was standing out in the dark and cold, wishing I'd worn the jacket with the gloves in the pocket as my hands got colder and number with each call sign that went by. I tried to help myself along by trying to figure out how long it might be until they got to the end of the list, but the list order appeared to be "the order they're written in", since there didn't seem to be the usual order by suffix or anything that I've heard used on the daytime 40m nets I've listened in on.

Checking In

Finally, the net control called for late check-ins and other club members. I decided to give it a try, someone else keyed up just as I was pressing PTT, so I let up and listened through their check-in. Another call for late club member check-ins, I gave it a try.

Net control couldn't make my call on the first go, but asked for me to repeat it with phonetics. I did so, he asked for a report on what I've been up to on HF, and I did that and turned it back over again. He got my call and my report and noted my check-in. I'd done it! Freezing in the dark with a wire ground plane on a broomstick and a 1.1 meter cable to my HT, with two adapters in the line (PL-259 to BNC, BNC to SMC.)

Now I've made my first contact outside the driveway, not counting a prior attempt to contact this repeater where they could hear me but couldn't copy.

10m Net: Good Thing I Didn't Wait

Once the 2m net was over, I went inside to see if I could check in on a second net on 10m. I had the HF rig already set up, but didn't hear anyone come on. After a while W6PD started calling CQ Grass Valley. I waited, after a bit he called CQ anyone and I tried to answer. He heard me calling, but couldn't pull me out of the noise even after I turned my power up all the way (100 watts.) I'm sure my 40m antenna, its orientation (Grass Valley is end-on, pretty much), its location and its poor parentage all contributed to the unsuccessful contact.

Which I why I'm hoping to get something else up soon. Nobody's answered my CQs on 40m, perhaps I'm not getting a signal out there to speak of, either. I might send my kid (KJ6TFT) out with my HT and my short wave radio, perhaps, and see if she can hear me then report back on 2m (I'll have the Kenwood here, which should be able to work FM simplex across town. Maybe.)

So, almost 2 months from license to first net check-in. With some wires on the end of a broomstick. :D

Received My First Radiogram Today

2012-01-18T17:12:00.000-08:00

A short while ago I got a telephone call from a nearby radio amateur named Bill, call sign W6WEM, to tell me that he had a radiogram to deliver to me.

The message was from Pat, WB5NKD of Oklahoma City. I don't know Pat, but she sent me a nice message encouraging me to check out getting on the amateur radio nets and to learn to handle traffic. It's a standard message, and I appreciate getting it. Thanks, Pat!

As it happens, at the time the call came I was looking up various nets on the internet (you know, that thing that's like a radio net but it uses wires instead of radio waves. Apparently it's pretty well known these days.) Specifically, I was learning about a couple of nets called the Triple H net and the OMISS net, which both came up on a search for 40 meter nets. While I recognise these are not traffic nets, that is nets whose purpose is passing messages over the radio waves, I've also been looking in to and listening to those.

I have a 40m dipole antenna up right now, and daytime 40m radio comes in very nicely. During my mid-day breaks from classes I've been hearing some daily nets on 40m that are traffic nets. I've also listened in on some 2m nets, but since these are on repeaters I haven't been able to participate, as I don't have PL tones on my old 2m transceiver.

Bill, who delivered my radiogram, told me that he's on the California Traffic Net. They meet nightly on 80m, I'm planning on listening in on the first available evening and checking in if my antenna allows.

I talked to Bill a bit about what I'm up to here amateur-radio-wise, and asked about his station set up. He's got a skywire loop antenna, a type of antenna I've been thinking seriously about since I got some negative comments about my idea of possibly putting up a G5RV antenna at one of the local radio clubs. I'm planning to go by his place and have a look, and learn some of the details of putting up such an antenna myself. Bill's offered to give me a hand, apparently tree work was his business in the past, which is really neat since about all I know about trees is how to prune them or cut them down. ;)

Once I get a chance to learn a few things, I'll pull together the bits to put one of my own up. Bill commented that loops give a really low noise level, which I've learned to appreciate as a really good thing. 40m is fairly quiet on my current dipole at times, but at other times it's really noisy. And it's never really quiet.

Tonight I'm going to take a another look at what I've got for feedline, and at least know what I've got so that I can hopefully ask intelligent enough questions to figure out whether I can work with what I've got, or pick up some new feedline to go with the wire I buy for the skywire antenna.

Getting a Start in Amateur Radio--After the License
All this relates to the subject of what do you do to get going in amateur radio after passing the test. I've been trying to document a lot of what I've been doing, hopefully giving others some idea of what the process is like.

You pass the test, wait a few days to show up in the FCC's database. Then...

Then it's pretty easy to take a few basic steps. Get a VHF or UHF band handie-talkie or mobile rig and find the local repeater. I tried that, and have managed it when I leave the house. That seems easy, but it only gets you so far.

On my first go at amateur radio about 20 years ago I joined a local club and attended the meetings, but this didn't lead to as much in the way of contacts or learning how to operate as I hoped. In part it was because I didn't quite get the thing about nets. That there are different nets for different purposes, aside from the traffic-handling nets. Like the nets that help you make contacts in different areas for awards while you're learning the basics of operating on the air.

That first club also didn't have technical people like me. They were mostly focused on search and rescue, and did a great job of that. But when I had questions about antennas or projects to build gear, they weren't really in that part of the hobby and couldn't help me much. There was one fellow, Joe Sanches, AA6FT, who came occasionally and gave a great presentation on Amateur TV who was very encouraging to me. He urged me to get an Extra class license (I've done it now, Joe!), and seemed to be doing a lot of things that I was interested in. But I was distracted by being a new father at the time, having less money for hobbies all of a sudden (as a result of fatherhood), and just not making a lot of connections in the hobby in the time I did spend on it. After a while I felt like I was doing someone else's version of the hobby, not my own, and it sort of slipped to the wayside.

This time I'm trying to focus a bit more, learn some more, and get more involved so that it doesn't happen that way again.

I've joined two local clubs. While there's no club here in my own community, I happen to live about midway between two nearby communities with radio clubs. Between the two clubs I've attended three meetings since I got my license, and had a chance to meet quite a lot of local amateurs. I'm even starting to recognise some of them, and I'm trying to memorize some names and call signs. At one of the meetings, my daughter (KJ6TFT) and I got invited to a post-meeting get together at a local Denny's, which was really neat. It gave us both a chance to get to know some people better and learn some more about both amateur radio and the other folks' other interests.

One of the things I've noticed about hams is that when you catch them off the air, they often don't talk about their amateur radio stations or operations. You have to ask about it. I expect it's for a number of reasons. One being that hams are pretty much ordinary people in spite of their hobby (hihi), and it's not normal social discourse to walk up to someone and say things like "Hi, I'm WX6XYZ and I've got a Whammidyne 2300 putting out a kilowatt on a 123 foot inverted vee plus a 200 watt four bander in the pickup driving a screwdriver with a bug catcher. How about you?"

Another part of it is that once the station is established and operating more or less normally, there doesn't feel like much to say until something unusual happens like wind bringing down an antenna or a power surge blowing part of the radio.

So, if you're a new ham, here's my advice to you when talking to more established hams--be prepared to interview the other hams about their stuff if you want to learn about it. Ask if you can go to their place and see their station, antenna, or whatever and ask them detailed questions to draw them out. It's how I've started to learn.

Another factor that affects me is that I'm pretty darn technical. Probably more technical than the average ham, in fact. So when they get that sense, they may get the impression that I already know anything that they might tell me, or be sensitive about possibly telling me stuff I may already know. But when it comes to amateur radio, while I know all sorts of electronic theory and such, I'm really not very knowledgeable about anything else yet. And even where I know a lot of theory, I know very little about the practical realities. I'm not very experienced.

So while I can calculate the effects of using, say, 50 ohm feedline versus 75 ohm, I don't know the practical effects of how big a deal it really is, and whether there are some frequencies where it matters and others it doesn't. While a ham who's had a bit of experience, but doesn't know a Smith Chart from a travelling wave tube, knows more than I do about whether to just hook up the wire I've got and not sweat it, or whether to go down to the shop and buy a cable made of the right stuff.

At any rate, I'm persisting and learning. I've also got a little more money to put into things this time around and I'm not trying to be quite as hairshirt about it all, which is helping, too.

73 de W8BIT

8085 Resurgent: Back to the MAG-85

2012-01-16T15:43:00.000-08:00

I took a look at my own website the other day and realized it's been far too long since I have updated certain items there. Most noticeable to me was my MAG-85 project, an 8085-based micro trainer. There are a bunch of things I thought I'd posted over a year ago, but the information isn't there.

Obviously I never did it. Sorry about that.

The front page image for the 8085 project is was a really ugly thing I took at a very interim stage while I was doing regular updates on the project. If I wanted to scare someone off the project, I think that picture is what I'd use. What a rat's nest!

A Very Ugly Looking 8085 Computer

Shortly after that picture was taken I built a real front panel and enclosure. It's been happily living in that enclosure for well over a year, but I never posted the info on it. In fact, I've just started taking it apart in preparation for making some improvements. Since I like to take pictures of my work for documentation purposes (like getting the right connectors back in the right places), I took some photos of the partially-disassembled unit as it is before I make the updates. Here's one:

A bit ugly with the top and bottom panels off, connectors and wires trailing out, but not so bad at the first photo.

Here you can see that it's not so ugly as before. The LED to the left of the LCD display is controlled by the 8085's SOD output. The eight LEDs below the display are controlled by the 8085's OUT 01 command and held in their state by a register. The eight switches below that are on the 8085's IN 01 port.

The program that's running currently reads the position of the switches and outputs a byte to the LED bank to match what it sees on the input. It also reads the keyboard and sends the ASCII + 0x30 character to the screen that it reads from the keyboard (which is in IN 00). The LCD display is on the OUT 00 port.

The four push buttons above the keyboard are, from left (red) to right:
RESET
TRAP
RST7.5
RST5.5

In the crude OS/monitor I have running on the MAG-85 now, TRAP acts as an "Escape" key that returns control to the OS. This allows miscreant programs to be stopped and memory examined any time, since TRAP isn't maskable.

RST7.5 is used as the user vector to the start of the application program in memory. In essence, this is the "GO" or "Execute" button.

RST5.5 is also a user vector that should point to a subroutine that does something and returns. Either the application program should initialize it, or it has to be initialized by hand in the monitor.

The keyboard itself uses RST6.5 to read a key value into a buffer, where an OS routine can pick it up/translate it, etc. The keycap legends allow for several uses of the keys. The typical use of the yellow keys is hexadecimal number entry. But they can also be used as arrow keys and fire button (9) for games.

The top row has the IN or Enter key in red, the backspace (BK) in blue, the (M) mode and edit/view (e/v) keys in gray. The edit/view key toggles a flag in the OS that switches between a memory protecting mode (view) and editing mode in the various modes. The mode key modifies the mode variable in the system to switch between Memory, Register, and I/O port viewing or editing. It's possible to change from editing to viewing and back again while in any of the modes.

Current Rework
My current plans for reworking the MAG-85 have to do with replacing the buttons used for RESET, TRAP and the RSTs, plus improving the ergonomics of the unit a bit by replacing the top and bottom panels, which were hand-made on hardboard, with some nicer CNC'd panels that reposition some of the controls (I switched off the unit more than once when I meant to switch on or off the backlight for the LCD.)

The four pushbuttons above the keyboard are some really awful buttons. They ring like bells, causing all sorts of debounce problems. I have both hardware and software debouncing on them right now, and it *mostly* works. I think part of why I stopped posting before was that I wanted to kill this problem before I posted, so as to avoid causing anyone else the headaches I've had with these switches. And, as you can see, those switches are still in there.

A sideline on the current work is also preparing for a couple of improvements that have been planned since the beginning, but haven't happened yet. One is to put a nice little door in so that the NOVRAM/EEPROM/EPROM memory can be swapped out without opening the whole unit. Right now I unscrew the end pieces then pop out the face panel to get at the memory socket. Which is not clean, quick, or easy. I have to get the cables all to go back to their places each time I put it back together. A couple of times I've pulled out one of the input cables by accident, then wondered why the keyboard or switches aren't talking when I get it back together.

The other is preparing to mount a battery pack inside, so that I can go cordless with this thing. A lot of what I've been doing in design tweaks is reducing the power used by the system. Finding a good brightness for the backlight, putting a switch on the backlight so that I can turn it off when I'm in good light, reducing the brightness of the power LED and the I/O LEDs, that sort of thing. As well as looking at my nascent OS to see if there are things I can do there that will reduce power while staying out of the way of the user's programs.

I'm also planning on adding another memory socket for an EPROM. It won't have a ZIF socket in it like the one that's there now, but I'm getting to the point of wanting a more permanent memory for the OS, with the NOVRAM left for user space programs. This may involve some rejiggering of the memory map, since for mechanical reasons I'd like to have the removable memory in the center of the PCB side to side.

I'm also looking at adding an expansion port or two on the new end plates, which begs the question of whether to use a standard connector with a more or less standard wiring for the port (like a PC's bidirectional parallel port) or whether to roll my own for the sake of less constraint on how the lines are used. Basically just bringing the lines from the I/O buffer registers straight out of the box along with power and ground. This is my preference for a number of reasons, but there's an appeal to letting the MAG-85 drive standard I/O devices, too.

The addition of a serial port, either at TTL levels or a standard RS-232C port is another possibility I keep playing with. I've kept SID available for this possibility, though I was tempted to use it as either a user digital I/O or a memory bankswitch I/O or something of the sort. Being able to connect the MAG-85 straight to a terminal would be really nice, so I'm leaning toward an RS-232C port.

But if I do that, I'll need a separate set of I/O routines for that port that allow it to be the primary user I/O for the OS. So if I do that, it'll probably be deferred until some other things happen first.

Like finishing the OS well enough to post it.

Finishing the MAG-85 Operating System
I haven't posted the OS yet because it's still in a fairly yucky developmental state. That and my test hardware still has the crummy switches that do nasty things to me at times, and there's lots of code in the OS just to try to deal with them that can probably come out once I've got decent switches in.

So my present software objective is to clean up the OS and put a bow on it so that I can "ship" it to a download on my site. I may end up cutting some of the features, but there's also the possibility that I'll end up cleaning them up because I've already got too much other code running around that uses them. The core basics are the ability to view and edit the system's memory, and execute a program starting at some given address. I'll guarantee that much.

I think the ability to view and edit register values is pretty well sewn, too. It's possible to bork the OS by doing something stupid here, but I'm not trying to protect the user from being stupid. Press TRAP (probably to be labelled ESC) and the OS will restart and reset any values it needs to function (I hope!)

The ability to view inputs and edit outputs interactively shouldn't be a problem, either, but it's not an immediate priority. If it happens effortlessly, it'll be in the initial release. Otherwise, I won't hold up the release for it.

I've also got another mode that is enabled in some versions for viewing/setting user variables in the OS, such as the RST5.5 and RST7.5 vectors, selecting different display formats, setting the size of the LCD, and so on. I can pretty well guarantee that the full-up version of this will not be in the initial release, though a cut-rate version of it may be. That would mean that you would set these variables yourself when putting the code on your own MAG-85.

If I do go to a design that uses two memories, one rewritable in system and the other not, I'll have to put these variables in RAM, or expect that they be set once and for all in the firmware. I'd like to be able to provide an EPROM at some point for people who want to build a MAG-85 and get up and running without having to put the OS in themselves. But if I do, I either need to put some system information in the NOVRAM memory space (like the height/width of the LCD display) or require that only one size of LCD be used with a specific version of the OS. Since I'm looking forward to building another MAG-85 with a larger display (perhaps 32 characters wide by 4 lines high), I'd like to keep the OS flexible. The initial display routines will only use a portion of displays larger than 20x2, but the user programs can use the larger displays and the OS can be updated later to have multiple display formats that the user can select.

But right now, I just need to drive a stake through its heart and get a workable version out the door. :)

New Call Sign, New QSL Card

2012-01-05T22:19:00.000-08:00

I'm afraid I didn't care much for the Extra class call sign I got from the sequential call sign assignment. It was AG6HU. Before it was assigned, I saw on AE7Q's site that I was likely to get a call from the range AG6HT through AG6HV. I would have been OK with HT or HV, but I was hoping I wouldn't get HU. The call sign is funky enough with the AG prefix, but with an HU suffix there's just nothing there to love.

I tried, I really did. I tried coming up with interesting phoney phonetics for it ("higher up", "hugely unpopular", "hic up", etc.) What really sealed that call's fate for me was when I tried telling it to people. It took a minimum of three tried to get it across, even when using the International Phonetic Alphabet. That's bad.

So I applied for a vanity call sign. I didn't rush right out, though I didn't dilly-dally, either. Knowing that I wasn't going to stick with AG6HU meant that I wanted to get a new call before establishing much of an identity with that call. I spent a lot of time thinking about what I'd want that'd still be fun to have 20 plus years from now.

Since retrocomputing and microcontrollers are both hobbies of mine, the call W8BIT seemed appropriate. That's what I put at the top of the list, and that's what I got. W6CPU and W6TTY were high on my list. I didn't realize it when I applied, but another ham applied for W6TTY a few days before I did, and got that assigned during the 18 day waiting period for my new call (not that it mattered, since my first choice was available, but an example of a good reason to have more than one choice and be prepared to not get your first choice.)

Another one that would have been a lot of fun is KO5MAC, since I'm a fan of the COSMAC microprocessor (the RCA 1802.) It's a bit more specialized than simply "8BIT", so it ended up as a lower preference. Beyond the first three choices I listed, I didn't worry much about the order of the other calls I put on the list relative to my preferences. Any of them were better than AG6HU, and I pretty well expected that things weren't very likely at all to go past the top three. KO5MAC would probably have been my fourth choice if I had arranged them. It's an awfully fun call sign, just like the 1802 is a really fun chip.

I considered having a call with my current favorite microcontroller referenced, the Atmel AVR, like, say K6AVR or W6AVR (no idea if these are in use or not.) But that seemed potentially even a bit more narrow than the COSMAC reference, especially when viewed from the perspective of 20 years from now.

I got my new call sign on the 4th, I'd already figured out what I wanted to do for my QSL card. I got 100 of them printed up today. Here's what it looks like:

Ready to Go, Almost
On the more practical side of amateur radio--making actual radio contacts--I'm still moving things forward. Yesterday afternoon I replaced the towels stuffed in the window where the antenna cable comes through with a purpose-made wooden feedthrough. It looks a lot less "redneck" than the towels stuffed in a window casement.

Unfortunately, I don't have a good ground to the transceiver in its temporary home yet. I'd hoped to have time to pull that in yesterday but time ran short. But that's next. I'm not too worried about the ground when I'm just listening in, but before I key the mike I want to have a good ground on the radio's chassis. Then I'll be ready to jump into 40 meters, and possibly 15 meters.

I've been listening in a lot on 40 meters over the past week, and I'm starting to get a pretty good feel for the band. Like what frequencies folks are using pretty commonly, what sort of traffic is going on when (daily nets, some of the weekly nets, and so on.) So I'm pretty confident I won't seem to be a complete and total lid when I do key up. Though I'm prepared to make _some_ mistakes, it's part of the learning process.

Then the next major step is to clear out my corner of the garage, put in an AC/heater unit in the wall, a raised floor, and a bit of insulation. A few more touches like a mecca ground plate and feedthrough panel then I'm ready to put in shelves and furniture.

Somewhere in there I want to get or build a decent morse key or keyer. All I have on hand right now are a couple of ones of about the quality that were in kid's science kits 30-40 years ago.

So long as my current antenna keeps me going, I'll just go with it until the new radio shack is done before hanging up a new multiband antenna. A G5RV has been highly recommended to me by at least two hams. I've got a good idea of where a full size one would go on my property, and I'm looking to see if I can fit in a double-size one at right angles, more or less, to the first. That'd (hopefully) get me on the 160m band, too.

Lots to do, lots to do. In the meanwhile I'm going to grab my HT and make some contacts on 2m simplex.

73

Got a Rig, Got an Antenna

2012-01-01T16:51:00.000-08:00

I've got an HF rig for amateur radio now. I've been trying to figure out how to get started since working with the VHF equipment I already have on hand hasn't been working out well for me so far. Based on what I picked up on my short wave radio it looked like the high frequency bands should do well here where I live.

Last week I got a used Kenwood TS-450SAT. It's a really nice older rig, the set-up I bought included the antenna tuner (thus the "AT" in the model number) and a good power supply (Astron RS-35M). It's capable of 100W out on all the HF bands (less in AM, 40W if I recall correctly.)

Next I needed an antenna.

Two days ago I fashioned up a quickie dipole out of some 3/8" cable shielding I had on hand. It was the end of a spool, I had about 80 feet. I cut two pieces about 35 feet long to make a dipole about 67 feet long overall once all was said and done. My time was short, I soldered some 12 guage solid wire on to an SO-239 bulkhead connector, soldered that to ends of each piece of braid, put loops in the 12 guage and tied a piece of rope between them as strain relief, then make a couple of end insulators out of short chunks of PVC pipe.

More 12ga solid wire went into the outer ends of the PVC insulators to finish the antenna's first incarnation.

The light was already failing, but I managed to go outside and run the antenna from a manzanita bush on a hill next to my home, about 20 feet higher than my roof. The other end went to an old bicycle inner tube looped around one of the vents on my roof. A poor installation, but all I had time for as it was about full dark by the time I came back inside.

A sixty foot piece of RG-8 with PL-259s on the ends ran from the center connector, through a cracked window, to my rig. I stuffed the crack with ratty garage towels.

My MFJ-259B reported that the SWR was out of bounds on 160m, good on the high end of 80m, so-so across 40m, worse on 20 and 17m, good in 15m band, decent in 12m, and barely usable in 10m. What the heck. I hooked it up to the TS-450S.

I didn't know if I was going to try sending anything when I hooked it up, but once I got started I realized I had my hands full just figuring out how to listen on my new rig for the first evening. I managed to listen in on a net on 40 meters and hear a few QSOs. The antenna brought in more than I get with the whip on my short wave radio (whew!), but is still wasn't all that great.

I'd noticed that the MFJ-259B said that the best frequencies on my antenna were all just above or at the high end of the ham bands I most expected it to perform at.

So yesterday I went out with my ham daughter (KJ6TFT) and we did a re-do on the antenna. I shortened it up a bit (between stretching and poor quality control in the initial build it measured out as a bit over 68 feet), did some mechanical touch-up, and installed it in a better location.

I was limited by the length of my RG-8 feeder line, the only one to my name at present as another length of Belden duo-foil cable turned out to have a kink in it where the center conductor pushed through the inner insulation to touch the shield. So we ran around the steep end of my property with a 100' tape measure for a while and came up with an idea we hoped would work.

We picked an oak tree at about the right distance at the top of the property (still below the hilltop, which my neighbor owns) to attach a 12 foot board with one end of the antenna. The antenna then slopes down to another 12 foot board with a 2x3 reinforcing board that's attached to the edge of my garage roof and the garage wall through a T. We were planning to use nails at some points, but went to screws when it became apparent during the hand-held test-fit that tension was going to be a lot higher than we originally thought.

How is it that antennas weigh ten times as much in the air as when you carry them in your hands? ;)

We spent almost the full day working out the niggling details of this "temporary" antenna installation. Besides getting on the air quick, this antenna is also intended to give me some idea of what I can expect to catch off the air here, let me know how the orientation it's at will work (it's north-south), and otherwise just give me some practical experience before I start any elaborate plans for a permanent antenna.

I learned a lot before I even got to the point of hooking it back up to my rig. Which is good. I can see several mistakes I would have made if I'd tried to dive into a permanent antenna design right off the bat. I've heard it said that a quick and dirty antenna takes just as much work as a full-fledged proper job, so why bother with the quick and dirty at all? In my case I can say that by using available materials and not expecting too much I've managed to learn a lot that will make the "real" antenna a much better antenna than it would have been otherwise, and I'll have a much better idea of what to expect without making too many guesses.

Once hooked back up to the rig, the extra altitude of the new installation showed its effect. I was hearing a lot more across all bands. The difference was huge. When I later disconnected the cable and checked the antenna on the MFJ-259B the numbers looked only marginally better, but then an antenna analyzer doesn't evaluate the location of an antenna, except as it affects the antenna's electrical characteristics. At any rate, the SWR is better across most bands (some got just a little bit worse), but the real story is in the reception. Which is much improved.

So now I just need to do a little more reading in my transceiver's manual to make sure I have the least clue about what I'm doing when I hit the PTT button. So I'd better close out this post and get to it.

KJ6TFT's First QSO, My First QSL

2011-12-21T16:59:00.000-08:00

My daughter's call sign showed up in the FCC ULS database today.

First QSO

I sent her out to the driveway with my 2M HT while I sat inside with my Kenwood TS-700A base station. I had a yagi up on the roof, in horizontal orientation so that I could try out SSB, but I figured at a distance of fifty feet or so orientation wouldn't matter much. I'd set the HT to the simplex frequency 147.510, and had been listening in on that frequency on the base station for a while to see if anyone else was using it.

The frequency was clear, my daughter was outside the house a way, I waved through the window to let her know to go ahead. She called me just fine, "AG6HU this is KJ6TFT." It came in clear on the Kenwood, I came back, "KJ6TFT, this is AG6HU. You're coming in five by nine."

"That's great! KJ6TFT."

"Do you want to give me a signal report?"

"Oh, yeah. You're loud and clear. KJ6TFT."

"Thanks. QSL?"

"What's that? KJ6TFT."

"It's confirmation of contact. Do you agree to confirm our contact?"

"Oh. I thought that was QSO. KJ6TFT."

"That's a communication. Like, Q Signal Out. It can be confusing. So, QSL?"

"Yeah, QSL. KJ6TFT."

"Great. Thanks. AG6HU clear."

"KJ6TFT clear."

You can read my daughter's account of her first contact here.

First QSL

After our communication I pulled up GIMP to make a special one-off QSL card for her. I printed it out on 110# cover stock and coated it with a clear fixative. That stiffened it up nicely. Here's my quick and dirty one-off QSL card:

Afterward, I let her know that she didn't have to give her call sign on every transmission. I also had a quick look at the Kenwood. The antenna wasn't plugged in at all! Worrying about polarization is pretty meaningless when you're putting out RF from nothing more than an SO-239 plug. Still, we made the contact. But next time I think I'll at least stick a piece of hangar wire into the plug. ;)

She Passed the Amateur Radio Test

2011-12-20T23:14:00.000-08:00

My oldest daughter, Amaryllis, went to take the Amateur Radio Exam this Saturday. I went along, for moral support and because I already knew the way to the exam site. Plus, she got to study while I drove.

She passed the Technician Class exam handily, and went on to take the General Class exam. She fell short of passing it by a few questions, but did well considering she hadn't studied beyond the Tech question pool and subjects. Maybe she'll want to upgrade this spring, I'm putting together an HF station to deal with the fact my house is in a gully surrounded by 100 foot tall VHF-eating trees. I suspect she'll want more HF privileges once she gets a taste of it.

She's blogged about her experiences here.

I took her up on the roof with me yesterday to put up a trial antenna for 2m SSB. I had her running the antenna analyzer while I made final adjustments to a four-element yagi on a fiberglass pole. She seemed to enjoy being part of the process and talking to me about how the antenna is supposed to work, what the numbers on the analyzer represent, and so on.

Antenna Hijinx

The yagi was a failure (terrain and trees win again), but our time together was good. The Kenwood TS-700A got one side of a nearby conversation on SSB, but it was down in the mud. The static was deafening. Next I'm going to see if turning the yagi to vertical will give me any improvements on FM over the three other antennas I've tried so far. Plus I'm going to see if I can't get a pilot line over a high tree branch with a bow and arrow (blunt tip) to pull up a 2m vertical and possibly a simple HF wire antenna to get started with once I've got an HF rig.

It'll go to the shortwave receiver until then to help me get a better idea of what I can catch here. The shortwave gets plenty of 80m at night, and picks up some 40 and 160m traffic, just with the built-in whip, indoors. It gets some 20m and 10m traffic, with hints of 15m, during the day. I think we're getting some beneficial knife-edge refraction off the surrounding terrain at 80m. I guess there's software to model this, it'd probably be worth my while to look into it before committing to a sizable antenna project.

As to 2m, at some point I'll get a more powerful rig--after I get the HF rig purchased. The Kenwood has no PL, but I'm going to try some FM simplex to see if that works better than SSB. If Amaryllis gets her call in a day or two I can send her out with my 2m HT and a car to see what sort of a pattern and signal strength we can get in and out of here from the nearby area. Plus, once school starts again I want to take a radio into class and do a little demo. Amaryllis can see what sort of signal we can get to the school (if any). Or I'll go if she'd rather run the Kenwood at home. We'll see.

Having a second ham in the house will sure be convenient.

Amateur Radio: A New Hope

2011-12-16T22:45:00.000-08:00

After my prior post wondering what I should do to pull together a ham shack for <$1000 or so, I noticed I wasn't getting much feedback either online or off. This is usually a sign I've asked the wrong question. Sure enough, I've gotten a response now that verifies that.

Fortunately I've had a distraction that's kept me from fretting too much.

My oldest daughter has been studying for her own ham radio license.

The First Harmonic Doesn't Fall Far from the Primary

She's been playing with microcontrollers for the past several months, learning the basics of electronics and low level programming. When I talked about some of the things on the amateur radio exam, they sounded familiar to her. I guess I got her interested.

She's been studying for about a month now, in spite of distractions from work and her other hobbies. Tomorrow morning she's going to take the test. A week ago I wasn't sure she'd be ready, her online tests were coming up more fails than passes (the online tests are a really great study tool!) Since then, we've had mini lectures on propagation, capacitors and inductors, and rules & regs. She's also had a chance to focus on her study a lot more this week, and take more tests to see more of the questions. She's scoring much better now, consistently passing the test with 3-5 missed questions. Good enough to drive down to a test tomorrow morning.

Hopefully she'll have a CSCE tomorrow. If not, I'll tell her my stories of how I failed my first attempts at getting my license and reassure her that another test will be available soon. The only way to fail is to stop trying.

My Plan, Revised

To get an HF set-up of the sort I want takes more money than I have now. I started writing down lists of rigs, the necessary bits to get them on the air (power supplies, antenna tuners, etc.) and realized I can afford a single or dual band mobile, not a base station. Kits aren't all that cheap, either, once I look at what I can build without much infrastructure and get something of quality with long term value.

So, 1st step: be patient and build up money for a more realistic station budget--as I learn more.

Step 2: Try some more things to get some QSOs with my 2m FM HT on simplex (like from the parking lot at the store while the wife shops for XMas) plus see if I can get an SSB or CW signal out of my home location with the Kenwood TS-700A 2m rig I've got. Its receiver isn't very sensitive (I think the quartz stones in front of my house convert more signal), but we'll see. Maybe I can adjust that.

I'll also play around with horizontally polarized omnidirectional antennas or put up a beam and reposition it by hand every so often (no rotator yet--something else that'll take money when other things have been dealt with.) I put up a wire yagi last week, but couldn't hear an SSB net that was scheduled with the 700. Maybe I can figure out why this week.

Meanwhile, I'll see what I can log from parking lots with an HT. :)

Best Starter Ham Shack for <$1000?

2011-12-13T16:04:00.000-08:00

In my research I've stumbled on a question that elicits a lot of opinions. What's a good starter ham radio rig to buy? There are a lot of answers, and working through the answers requires a more specific question is what I've learned so far. So here goes. Short form first, more background below.

I'm looking for:

A fixed base rig to operate off wall power.

80m to 10m, 160m is greatly desired, 6m would be a nice frill.

Rig price on the order of $500 or so, depending on extras:

With all the bits--filters, power supply, feedline, key and/or keyer, mike, antenna tuner, etc. I'd like to bring the bundle cost in at about $800, up to as much as $1000 once the last insulator, connector, and screw is in place.

Furniture and basic facilities like light, heat, and air isn't included in the cost,

but a lot of little things like the antenna feedthrough, cable, switches, and connectors are, which is why I'd like the big pieces to come in around $800.

I'd be willing to go higher if I felt really secure that I'm investing in something I'm likely to get much more or better use out of, but I'd still be capped about about $1200-1400 for now, anything more would have to wait.

Detail
My present home location appears to be best for HF work, so that's where I'm going to concentrate for now. I expect to pick up a good enough 2m rig to be able to hit the local repeaters for the sake of keeping in touch with the local hams, but VHF isn't where I'm looking to do my regular operating. This rig will be for a fixed station operated when the power is on, so portability and power conserving reception is not a factor, especially when weighed against receiver sensitivity and other such factors.

Antenna
I have plenty of space for an antenna, but I'm not expecting to start with anything sophisticated in the way of masts--trees will probably be my initial supports, or a small mast off the top of my garage. I have no fixed idea as to whether to build or buy my first HF antenna. I'd like it to be multiband. I'll look at ideas from stringing up a center-fed 12ga wire dipole to a quad band yagi with a rotator.

For the initial antenna set-up, I'm willing to compromise with the expectation of getting more or better later. But I want to start with something good enough that I'm not cut off at the knees while I'm still getting a feel for what I'm up to. It's worth noting that I have an MFJ-259B antenna analyzer on hand.

Operations
I don't know what my primary mode is going to be yet. I want to work CW and SSB. I'd like a rig that'll let me dabble a bit, so I'd prefer it to not have any major weaknesses even if it's, say, the greatest CW rig ever built. I'd like to try some digital modes, some SSTV, and some ATV.

The extra equipment for these other modes isn't included in the cost, I just want to be clear that I'd like a rig that can do it at least well enough to get started and figure out if I want to put more money into it later. So a rig that can handle the duty cycle these modes impose is probably going to be necessary.

QRP isn't where I'm looking to start here. I've already got my site working against me, and I really don't know what it's going to take in the way of power to work from here. So the rig should probably be about 100W or more until I know--unless you can tell me better.

I'm expecting to build my own QRP equipment later. The rig I'm looking at getting should be a solid workaday affair, I'll have fun building watch battery wonders later. ;)

QRU?
So, fellow hams, where does that put me? An old FT-450 or TS-480? Or one of the new "shack in a box" rigs with some extras? Would I be better off springing for a good beam and rotator now, or will a wire dipole hung from some spruce trees get me enough QSOs to keep me going until the money reserves and operating experience build up?

Your opinions are welcome. I know that you can't tell me exactly what I should get. I'm just looking for opinions more seasoned than my own wild guesses. I just want to get an idea to start out reasonably effectively, while keeping the spending down enough that it won't ruin the hobby even if nothing I do works out as planned. ;)

New Ham Progress: Working Toward a Working Station

2011-12-10T22:31:00.000-08:00

It's been 3 weeks since I got my CSCE for my amateur radio license, two and a half weeks since my license appeared in the FCC database. Each day I've been working to make material progress to set up a station and start operating. So far I'm not fully "on the air", though I've made a lot of progress.

I passed the tests! Now what?

Getting a station up and running could happen quickly through purchasing a "shack in a box" transceiver with antenna, feedline, and accessories and setting them up. The set-up of the antenna, feedline feed-through, and learning to operate the transceiver and the aavailable ba would be no small feat in and of itself. But I'm taking a bit slower path.

As I progress, I'm learning a bit more about what I've got to work with--hopefully leading to better decisions when it does come time to lay out for equipment.

Starting Point
While I had a ham license before, I did very little with it. I had a mobile 2m rig in my car that I used on the local repeater. I helped at a local long-disstance charity run. I hoped for more, but that's all I did. I never really built up a station or even learned the routine on simplex operations.

Since then I had a friend give me a Kenwood TS-700A all-mode 2m rig. I can't locate my old IC-230 mobile rig, it's around somewhere, but I haven't found it yet. No matter, it's not much use to me in the present day. The 700A is a decent rig, but the receiver is pretty insensitive. Even if I just use it for SSB and CW it'll need a preamp and probably a power amp. Because of my location.

I've moved since my last time around with ham radio. I used to live in a fine location, now I live in a place where I'm poorly situated and surrounded by thick VHF-eating trees.

I also turned up about 60 feet of RG-8, a couple of awful little straight keys, and some other odds and ends.

Moving Forward
VHF will be important to staying in touch with local hams, but I need some tools that can deal with my location. For less than the price of a preamp/amp combo for the Kenwood TS-700A I can get a mid power, more flexible, more sensitive current-production 2m or multiband VHF/UHF rig. I still expect to have fun with the TS-700A down the road, but for normal workaday comms, a new 50-75W 2m rig would make more sense.

I did buy a little Yaesu FT-250R handheld, but it can't hit the local repeaters even with an external ground plane antenna mounted about 40' above grade. I built a simple yagi for testing, too, but I'm between repeaters so I'd like to use an omnidirectional antenna for general FM. The yagi was built to see if I could manage any SSB here. So far no luck but this is still work in progress.

More Site Assessment
To get a better idea of what might work here, I picked up a Grundig G3 shortwave receiver last night. I've been tuning around through the ham bands to see what comes in. MF/HF is definitely more promising here than VHF. It seems (so far) that 160m and 80m will be good here at night, with 20m being a decent daytime band. The jury is still out on the other HF bands. I need to put in an external antenna for the G3, so far I've just used the little whip on top.

Build or Buy
While I expect to build equipment in the future, I'm also expecting to establish the station with solid purchased equipment. Whether new or old I'm not sure yet, I have to spend more time with other local hams to find out my options. But prebuilt equipment will allow me to operate while I'm building other rigs--QRP rigs or whatever--plus it'll act as test and calibration tooling for my scratchbuilds.

From what I can see so far, I think I'd be just as happy at this point with solid equipment from any time in the past 25 years or so as I would with new stuff. For example, something like the late-80s Kenwood TS-440S or Icom IC-765 look like they'd still do fine today for my present needs. Maybe--I'm still guessing at this point. So I need to learn more and get some idea of price differentials and all that.

Meanwhile...my ground rod is in, I'm clearing an area for my station that'll get its own AC/heater unit and antenna cable feed-through. I'm experimenting with antennas and mast mounting positions and otherwise trying to make it so that when I do have equipment, I'm prepared to do something at least somewhat effective with it.

A Neat Modern Retro Computer: The New Elf II

2011-12-06T11:39:00.000-08:00

My first computer was a version of the COSMAC Elf computer. It was a simple little computer, costing about $100 in 1976-77. The joy of it was that is was a real computer, and yet it was direct enough in its design philosophy that every single thing about it was understandable and controllable.

I wasn't the only one enchanted by this small computer system, or to have it as a first computer.

Marc Bertrand has built a new, modern version of the Elf computer, visible at his web page. It's not only got the original video interface of the Elf II, but a nice LCD display driven by a PIC microcontroller. It has heaps of I/O ability through several interfaces, nicely controlled by some Altera programmable logic.

Have a look, it's a sweet little system with a layout very reminiscent of the original Elf II computer.

This isn't it, but it's a little test circuit for the 1802 microprocessor used in Elf systems that makes a nice LED blinky:

A simple test circuit for the RCA 1802 processor used in the Elf computers

CNC Enclosure: A Home for My MicroCarve A4

2011-11-28T12:58:00.000-08:00

I originally set up my microCarve A4 on my workbench as I got the various bits and pieces put together and checked out. This was a convenient place to do the work at that time, but once everything was working, there were two significant problems:

It was in the open air. Sawdust and plastic chips were flying everywhere.

I wanted my workbench back for other projects!

So it was time to take time off from making cool CNC projects and time to make an enclosure. I spent quite a bit of time thinking through what I wanted. If I put the computer and CNC side by side, it'd take up too much room in the shop. I tried a test arrangement of putting the computer below the CNC, the display above the CNC, and the keyboard and mouse in a drawer just under the tabletop that the CNC sat on. This did my neck no favors at all.

Finally I settled on putting the CNC itself a bit higher, with the computer completely underneath it. This worked out, barely. I had to replace my old CRT monitor with a lower-profile LCD display to get the heights I wanted. It was worth it.

The desktop is at 26 inches above the floor, the bottom of the CNC is at 48 inches above floor level. It's low enough to handle the tools, parts, and everything else inside as well as keep an eye on the machining as it goes, though an optimum height would probably be a bit lower. A different arrangement of the computer stuff down below could probably allow someone else to make theirs about six inches shorter, if they don't mind looking down at their computer monitor rather than propping it up on the computer cabinet for a comfortable height, as I did.

The desktop holds the computer, monitor, power control center, CNC power supply and Gecko G540 control unit, wireless network hub, keyboard, mouse, and an occasional can of soda (with care).

The CNC box has removable panels on the back and sides. The back panel is in three sections, so that a middle section can be taken out for working with stock that's too long for the enclosure. This leaves a panel at the bottom to catch chips, and a top panel to trap some of the high-flying chips. If necessary, one or both of the front doors can be left open with longer pieces, a bottom panel will still cover the lower three inches of the front to trap some of the chips from spilling out. I thought about making sectioned doors, but this project was already getting too complicated.

The top box can lift off of the base with the computer desk. It has small feet that rest inside the uprights on the base and lock it in, as well as a pair of angle brackets that screw into it. Basically the power and control cables that run into the box through the two PVC feed-throughs are are disconnected, the box is lifted off the top of the base (a two-person operation when the CNC is in there!), then set on its feet where ever it suits you.

The base has casters on the bottom, so I can roll it around the shop or out onto the concrete apron outside if I feel like doing my CNC work under the sky. ;)

I plan on adding a vacuum motor and dust trap below the desktop when the urge to take things a step further strikes. I'll cut another feed-through into the box for the vacuum as well as an air intake for the enclosure. Until then I'll just be reaching in with the hose of a nearby canister vacuum to clean things out.

Amateur Radio Station from the Ground Up

2011-11-27T17:58:00.000-08:00

I earned my amateur radio license about a week ago, and it posted in the FCC's data base last Wednesday. My call sign is AG6HU. Vanity call sign, here we come. ;)

Getting on the Air
Still, it's a good enough call sign to get me on the air.

I have two radios at present, both pretty old. One is an Icom IC-230 that I got from a ham in Hayward back in 1986 (another time when I was preparing for a license but didn't get one.) It was my one and only rig when I was KD6KGV. Presently, it's lost in storage some where. I remember coming across it sometime in the past year, so it's not completely lost. When I got it it needed some TLC. A little work and some new crystals and I was in business when I got my first license in 1992.

The other is a rig a friend gave me back when my first license was still active. It had been his father's and he wanted to find a good home for it. Unfortunately, I never got on the air with it. It's a Kenwood TS-700A, vintage 1976 or so. It's a pretty rig, and it was a lot easier to find than the Icom when I went into the garage this last week. However, when I turned it on and started listening to the local repeaters I found that the frequency readout shows a different frequency than the actual frequency of the repeater--by a lot. So I'm afraid to transmit on it until I can recalibrate it. I have the service manual, I just need to pull together some test equipment beyond what I normally use. Back to the garage I go, for more boxes.

Doing What Can Be Done

Meanwhile, I picked up an eight foot ground rod and a clamp at the hardware store, I already had a bag of rock salt on hand. I've got a place picked out in the back of one of my garages for my station set-up, and I was planning on installing the rod just outside. I've got two garages, both attached to the house. The spot I picked has a nice window, and I'll be able to install a combination heater/cooler unit in the wall beneath it.

I decided to use a technique similar to that used by Roger Halstead, K8RI. I had a heavy duty hose with no connector on one end that I slipped over a piece of full conduit (I didn't have a straight enough piece of thin wall tubing on hand). Then I put on a hose clamp, hooked it up to a hose bibb, and I was ready to do some hydromining.

My house is built on rock in a cut that was made to make enough flat space to build the house, run a driveway and so on. So a rock drill and blasting charges would be the most appropriate tools for making a deep hole. However, there's an area around the foundation of the house that was excavated for the foundation. My thought was that I'd put the rod into the area next to the foundation that was excavated, then backfilled.

Unfortunately, I couldn't get more than two feet deep this way. It appears the backfill is primarily what came to hand most easily:rock. So I changed my plans. I'll admit that while I was fighting with the conduit under the eaves of the house the idea of putting down a subsurface wire grid occurred to me, but that would be a weekend-long project at least.

I also have a retaining wall that forms the back wall of my far garage. That puts the ground rod a bit farther from where I want to stack my rigs, but not much further. If there's a real problem I can always move the station from one side of the garage to the other, even if it means being a but farther from the window.

So I climbed up the hill and tried again. It took about ten minutes, but I managed to get a seven foot deep hole without too much trouble. It's a good thing I used schedule 40, I had to ram down through some of the sandstone at two places, I don't think thin wall tubing would have managed that as well. Though schedule 40 required me to wiggle the tube around a bit to clear enough of a hole for the thick walls of the conduit.

I'm Grounded
I left the conduit in the hole until I had the ground rod ready to go in. In the dying light (hence no photos until tomorrow) I pulled out the conduit and ran in the ground rod. A few blows with a sledge seated it nicely at the tip. A few more minutes with a shovel dug a trench out around it that I poured a bag of rock salt into. It's raining off and on here right now, so it should have the ability to diffuse nicely over the next few days and raise conductivity.

New Toys
Meanwhile, I ordered some new equipment last Wednesday after I saw my call appear in the FCC ULS and realized my current rig wasn't going to get me on the air any time soon. I've got a new MFJ-259B antenna analyzer/frequency counter/cable tester/bottle opener headed my way with a full slate of accessories. I've also purchased a Yaesu FT-250R HT to get me in touch with my local hams while I fuss with the Kenwood and start working toward building up a station for HF work.

Frankly, test equipment is one of my favorite things in the world. Amateur radio lets me justify more test equipment. That's a good thing. :D

First QSO Soon
Each day I'm working to do something material toward getting a station running. My first QSO will probably be on the HT once I get it out of the box and charged up. But I'm looking forward to using the Kenwood once I get it sorted out, and getting connected with the local amateur community to learn about more types of operation. Plus getting or building more equipment to do even more.

Amateur Radio is Contagious

2011-11-19T11:35:00.000-08:00

A little over a week ago I stopped in at a local Radio Shack to pick up some connectors. My supply of 1/8" phono connectors was running low, I keep some on hand for off-the-cuff projects and I'd recently pulled out the last one and used it.

While I was getting rung up, I chatted with the fellow behind the counter. He was another electronics enthusiast, and we shared our laments over Radio Shack's diminished stock of electronic components for hobbyists. He mentioned that he's a ham as well, and commented on how easy it is to get a license these days.

Well, that got me to thinking. So I had a look online. No Morse code requirements at any level, plenty of tests nearby on a regular basis. I wondered how I might do on a test. So, just for the heck of it, I found an online practice test and took it at Technician level (the lowest level.)

I passed!

How about that? So I tried the next level up. A General class license test. I passed that, too. But I missed a few more questions. Fortunately the test was pretty generous about how many questions you can miss. What next? Well, there's the highest level test. Amateur Extra class.

It's just an online test, what have I got to lose?

Apparently nothing. I dove in. This one was more difficult, but I was getting lots of questions on areas I'm already pretty good at, like video and amplifier circuits.

I passed it, too. Register shock and a little bit of horror at the back of the mind. I stared at the result at the bottom of the page saying "You Passed!" It didn't seem possible that maybe...maybe...I could get an Amateur Extra class license.

Well, life is busy and all that so I laid it aside for a day. But the results kept nagging at me. After another day I was back on, repeating the tests. I'd just gotten lucky, there's no way I could pass all three tests cold. So I tried again.

Technician-pass.
General-pass.
Extra-fail. Aha! I knew it. I missed by...one? One lousy question?

Where was I weakest? OK, operational procedures and rules and regs. No surprise. I'd just been making my best guesses all they way through those questions any way. How am I supposed to know what treaty does what or which part of what band I could send transmission X in? Some of the band questions weren't so bad--they'd ask something like "What part of the X meter band can you..." and only one of the frequencies listed in the answers were in that band. No problemo. But if they listed more than one frequency in the correct band it was "pin the tail on the donkey" time for me.

So I went out to the FCC website and pulled a copy of CFR, Part 97 and gave it a read. I got through about 1/3 before my forehead hit the keyboard (actually I'm pretty used to reading dry stuff, and it wasn't that bad. I just couldn't wait to try another practice test.)

Then I went back and tried the tests again. Tech: pass. General: pass. Extra: fail by one. Argh! Off to the ARRL website to look up information on current frequency allocations. I ran into a whole bunch of those questions on the last round of online tests.

Repeat: Pass, pass, and...pass! Woot!

But those scores weren't all that great. Let's work on that...
I've been studying in all my free time over the past several days. I picked up a book to make it go easier. The time it saved me in web searches alone made it worth the price:

Today, just over a week after a short stop for five dollars worth of parts at Radio Shack, I went in for the real test:

I passed all three exams!

What I haven't mentioned is that this interest of mine started a long time ago:

Low Level Computer Teaching Options

2011-11-09T15:10:00.000-08:00

We have a current discussion on the COSMAC Elf Discussion Group that centers on the idea of a small computer to teach low level computer concepts. Many of us in the group got our start with the COSMAC Elf as our first home computer. It is a small, simple, inexpensive computer. One of its finest points is that it is simple enough that a person of ordinary intelligence can understand how every part of it works, down to the lowest detail.

The place for a small teaching computer, as we're discussing it, lies somewhere between electronics and the standard non-computer science introductory computer programming class. It's a matter of teaching what the components in the system do, and how they do it. This becomes a model of what happens inside more powerful modern computers at larger scale. Such as in current desktops, laptops, tablets, and smartphones.

The COSMAC Elf, this version includes video graphics.

Is anyone using something along the lines of a microprocessor trainer in the classroom today outside a college level EE class?

Personally I can see two general approaches to this, with several possible variations on the two themes. Let's look at them, then I'll go into Blue Sky mode to talk about what I sort of wish for.

Some Ways to Bring Computer Hardware into Class
One is to fake it entirely with present-day hardware. After all, if it's possible to do a complete chip-level simulation of an 8-bit processor in Javascript, it shouldn't be much of a stretch to simulate an entire simple 8-bit microcomputer in a program with the ability to "see" all the operations inside simulated on the screen.

The problem is that this still really fails to make what's being taught "real". To the students, it becomes just another show to watch--one with no particular interest to most of them.

The other approach is to use an actual old microcomputer in class, like the Elf, with the students handling the system, measuring voltages or using logic probes to "see" the signals in the computer. Something more sophisticated would be using chip clips with LEDs on the various lines as a sort of multi-line logic probe. (Here is a place where an Elf or other RCA1802-based system would shine. The 1802 is a fully static processor. It can run at clocks speeds from 0Hz on up to its maximum clock speed, with clock changes on the fly. I have literally clocked 1802 systems by hand by connecting and disconnecting the clock line to +5V and Ground lines, counting out machine cycles as displays show the status of various system lines. There are not a lot of computer systems that can do that!)

Between these two lie many other options. One would be to have a hardware board that connects to a modern computer through a common interface, like USB, where some I/O devices could be visible controlled by the computer (via lights, motors, etc.) and with lines exposed that can safely be probed by the students.

Another would be using a more modern hardware platform, perhaps based on one or more microcontrollers that emulate the function of an older system, exposing such things as memory access, control signals, and so on to the students. The board could include displays and LEDs to show the status of the lines, internal pseudo-registers, and so on. The operation of the entire system, both inside and outside the simulated ICs, could be made available to the student's eyes.

Part of what needs definition is the acceptable limitations of the system. In my own case, I see such a system as being an introduction to low-level hardware operation and control of that operation through software.

Blue Sky Dreaming
If I could have what I wanted without any effort on my part or a significant amount of the school's money, here's what I'd like:

Step 1
I would want to introduce a basic system that's very similar to the original Elf of 1976.

It would have:

Toggle switch inputs (to associate signals with data and to help teach binary),

A binary LED display and a two-digit hexadecimal display,

Very limited memory (about 128 to 256 bytes)(to teach how much can be done in limited memory, and to limit the size of early programs to sane sizes.

Exposed memory and I/O lines, possibly with LED monitors

Extra monitors, like maybe dual color LEDs to show data direction on I/O ports, etc.

A simple machine language with whole-word mnemonics.

The ability to operate at extremely low clock speeds (0-100Hz) as well as higher speeds (1-10MHz or something like.)

Step 2

Hexadecimal Keyboard

512B to 1024B of RAM

After the first few lessons, the toggle switches would get old and I'd want to introduce a hexadecimal keypad. This would teach hexadecimal, and continue the association of computer instructions with numeric values in the computer. Presumably the connection between signal levels and numbers has been made using toggle switches.

With the easier input technique, it'd be nice to add some more memory, up to something like 512 bytes to 1 kilobyte.

Step 3

Keyboard with instruction mnemonics and hex digits

Perhaps more memory, up to about 4K

Next, a keyboard would be attached. Perhaps writing software to interface the keyboard to the system would be one of the Step 2 projects. While I'd be tempted to use an ASCII keyboard, I think a raw matrix keyboard would teach more. On this keyboard, machine language instructions and hexadecimal numbers would be mapped to each key. This would again speed programming, and reduce errors. The simple machine language I envision has a particular addressing mode associated with each mnemonic, so there's still no assembling of code required.

Step 4: A larger step
Next, I'd move to a more abstract level. I believe that the activities prior to this point would teach low level operations well enough to take this jump and still be able to show the connection between the two.

For step 4, the computer would get:

More memory. Anywhere from 4K to 64K. Perhaps it would start at 4K and grow as the students hit the limitations of each memory size.

A terminal connection to a current generation computer for keyboard and display, or an encoded keyboard and some other form of text display.

New firmware (probably activated from on-board with a mode switch), which would provide a fairly sophisticated command line interface with command editing, recall, etc., as well as an interactive programming language. The specific language doesn't matter too much, it could be a BASIC, a bash-alike, a LOGO, or an interactive form of some other compiled language.

Mass storage. Probably some modern semiconductor memory.

The point at this step would be writing high level programs to perform low level actions like those seen in the earlier steps. Seeing line levels and I/O operations performed, using bitwise operators, seeing the signals represented as numbers of various bases within the language (which I'd expect to support at least binary, hex, and decimal for representation and constants.)

Step 5
The final step with the low level computer would be to produce more sophisticated programs. These would be longer programs, probably projects done by groups of students over a few weeks in class. At this point the understanding of the program control structures and data structures should be a bridge to programming in the chosen language directly on the modern computer.

Final Thoughts
These thoughts are somewhat half-baked as they stand. I or someone would have to do some more work to really define this and turn it into hardware and software and a curriculum to go with it. Some points that need considering are the demarcation between this and a robotics class, common in many schools now (including the one at which I teach.) Also, how much class time does this merit? And so on.

Personally I think that using a micro trainer level system is simple enough to be mastered by most middle-school level students. I've got some actual experience with students to back that up, in addition to my own experience (I was 14 when I constructed my own Elf.) For the students, the information not only gives them an understanding of the underlying technologies of current systems, but would open the doors to embedded systems, far more common than conventional general purpose computers. Either way, it would make the computer far less a piece of technical magic controlled by somebody else and far more something comprehensible, and therefore controllable, by themselves.

Some related work--a 4 bit TTL Processor.

The fact is, all the steps above would probably be unnecessary and involve too many changes to the hardware platform to be practical in class. A more reasonable approach would probably be to go from a slightly more capable Step 1 computer directly to Step 4. This would reduce the opportunity for student disorientation as a result of seemingly constant hardware changes, and still be enough to get the key points across.

The activities I envision for Steps 2 and 3 could be either dropped or performed in either the initial or final configuration of the system. This would also simplify the system itself.

MeshCAM: An Inexpensive Commercial CAM Program

2011-10-21T15:20:00.000-07:00

I was recently contacted by Robert Grzesek, developer of MeshCAM, a 3D CAM program. He'd seen my earlier article where I express some frustration with "free" software, particularly for CAM. The free software I tried usually did simple rasterized cuts of the object loaded, with the result that a lot of the design's detail was lost.

Robert offered me a free copy of MeshCAM if I'd blog about it. I took a look at the product information online and took him up on his offer.

MeshCAM is in the same price range as the other commercial CAM program I've been using--it's a hobbyist-affordable program. This is very nice, as so much of the available software is well beyond the budget of an amateur, or a small business where CAM work is a sideline without a large budget.

It's documentation and the tutorials are very good. Having recently gone through some tutorial-based training with some other programs that are from much larger companies in the past few days, I'm pretty well up to speed with what can go wrong with a tutorial. The MeshCAM tutorials are up to date and in sync with the current version of MeshCAM. They describe the process well from the basis of someone trying to get a specific task accomplished, they're not just a description of what appears in the menus.

At first, I wasn't sure that double-sided machining for full 3D objects was going to be covered, but it was, I just needed to stop anticipating possible problems quite so much.

Working with MeshCAM itself, I've opened up the provided files and a couple of files of my own. For the file types it accepts (STLs and DXFs, in addition to its own MCF format, plus a number of 2D image formats for image-based height maps), it opens the files without a problem and displays them properly. Wavefront OBJ files would be a nice addition, but then that's why I've got the open source program MeshLAB (which has no relation to the MeshCAM line of products) which is frustrating at times, but mostly does the job of object type conversion and it's free.

Above is an example of MeshCAM's display of an object. The way MeshCAM displays its axes is a bit cartoonish, but at least you won't have to worry about missing them. They can get in the way of small objects in the display screen. There may be a way to deal with that by changing the way they're displayed, but so far I've just moved or rotated my objects away to view detail then moved them back.

The thing that makes MeshCAM stand out for me at this point is its finishing abilities:

It has built-in multi-pass finishing. I've managed to get the same results from Cut3D through a work-around. There, I create a finishing toolpath for one tool, save those toolpaths, then go back and define a different finishing pass, then save those toolpaths, and run them on the CNC one after the other.

MeshCAM doesn't require this. It gives a great set of finishing options for multiple tool passes right out of the box. I'm presently working on a model specifically to take advantage of these capabilities. Since much of what I'm doing is intended to have a high level of detail, I'm looking forward to seeing what comes off the CNC when I use MeshCAM to build the toolpaths.

MeshCAM displays the toolpaths it generates in the 3D view once they've been calculated, which gives a good first-look check to make sure that things came out right. There's no preview of the cutting operation built in to MeshCAM, however, as in Cut3D. Instead, a separate program, CutViewer is offered. Or you can do a "dry run" in most CNC control programs like EMC2 or Mach3 to see what the cutting will look like, at least as far as tool head movement is concerned.

The previews of the cutting operations have been one of my favorite features of Cut3D, so it's a feature I miss in a CAM program. I've gotten a higher degree of confidence from using this to see how the cutting operation will proceed ahead of time--the order of cuts is not always what you'd expect. The ability to check this during the CAM operation is very nice.

So I'd recommend planning to add CutViewer to your purchase if you buy MeshCAM, or make sure you're comfortable with your CNC control program's preview abilities. I'm using the preview abilities of EMC2's Axis view, myself.

Once I've finished the models I'll be trying out with MeshCAM, I'll be reporting on the final results. I'm planning both a flat relief object and a full 3D, 2-sided object.

Stay tuned...

Objects of Rotation in Google Sketchup: A Problem of Nomenclature

2011-10-20T22:37:00.001-07:00

I've been using Google's free Sketchup program for some 3D object designs lately. I've been using it for a while, but I only use it off and on, so my expertise is growing slowly.

Tonight I wanted to model something based on an Object of Rotation, which we all remember from math class is what you get when spin a shape around an axis. This is usually a trivial thing to do in both CAD and 3D design programs like AutoCAD, Lightwave, and so on. I couldn't remember how to do it offhand, so I did a quick search, expecting "sketchup object of rotation" would get me there in moments.

Technically Accurate, but Useless
I soon got lots of results for "Rotate Object", including a Sketchup tutorial video link. Unfortunately, I realized about 30 seconds into the video that it wasn't what I was looking for. It's a very nice tool for rotating an existing object's position around some arbitrary center of rotation, and possibly replicating it in a pattern around that center.

Nice, but not what I needed.

After a few frustrating attempts to rephrase the search to get what I wanted, I ended up just doing a search on what I knew is usually created as an object of rotation: a rocket.

"Sketchup rocket" yielded a couple of promising results. An amateur rocketry buff had instructions for drawing model rockets in Sketchup. The instructions for the nose cone were: how to draw an object of rotation in Sketchup.

Words Get In the Way
The tool for creating objects of rotation in Sketchup is the Follow-Me tool. In Sketchup terminology, an object of rotation is called a Lathed Object. Which makes perfect sense, if you already know it. (Thank you for the meme, Arthur Conan Doyle!)

So, to successfully search for how to create an object of rotation in Sketchup, use the terms "sketchup lathed object" or "sketchup follow me tool" to get what you want.

Hopefully this will show up when you search for "sketchup object of rotation" and save you some grief. ;)

CNC Rooster: Third Time's a Charm

2011-10-03T21:24:00.000-07:00

In a prior post, I'd made a mistake handling the material when cutting a full 3D object using gcode files generated by Vectric's Cut3D CAM software. After that I tried again. That time things were going swimmingly until I got some gunk on a leadscrew that hung up the X axis and ruined the cut.

Well, I tried again today. After doing some preventative maintenance on my microCarve A4 CNC, testing it thoroughly and making sure of myself as well, I managed to turn out a small urethane rooster:

Rooster, Side A

Rooster, Side B

The part turned out very well. The whole time the second side was cutting, I was fretting over how good my alignment would be. It turned out to be just fine.

The beak looks worse than it actually is because of a loose bit of plastic that'll come off when I scrape it with a thumbnail. It isn't perfect, however, because of the overcut depth I specified for the first side's cut. It's too deep for the thickness of the beak, and though the overall alignment of front and back side is excellent, the beak is at an angle, so one side is lower than the other. If I hadn't specified such a deep overcut, it would not have cut through this way.

Still, it'll clean up nicely.

Further Observations

The facets you see, particularly in areas like the chicken's breast, are part of the original 3D model. They aren't machining flaws. On the second side I cut the machining marks that are there are a little deeper than they should be because I trimmed my tab sizes down way too much, so they flexed a bit during machining.

Still, the overall quality of the part is such that I could clean it up to use as a casting master easily, if I were going to duplicate this part.

The Materials

The prior two tries were done using NC Proofboard, a urethane foam board, with densities of 60 and 48 lbs. per cubic foot. This last one was done in Butter-Board, which has a density of about 64 lbs per cubic foot. All are machinable plastics from Golden West Manufacturing.

60# NC Proofboard
The 60# proofboard was a very nice material. The cell size of the foam is very, very small and could easily be coated to smooth it enough to use a part made from it as a casting master. In fact, the mold release might be sufficient. It's very tough, and machines like a dream.

48# NC Proofboard
The 48# proofboard machines very easily as well, but tends to be a bit more brittle in thin sections than the 60# board. The cell size is about half again as large, but still small enough to be easy to coat, it'd just take more to do it--some sort of filler rather than a primer coat or a thick mold release agent.

Butter-Board
The Butter-Board machines to a fine, smooth surface. It takes a little more care in feed rates than the proofboards, which have a lot of resiliency thanks to being foamed products. But the completed part has an impeccable surface so far as the machining makes it so. It's not as tough in thin sections as the 60# proofboard, but it's stronger than the 48# board in thin sections in general, though it tends a bit toward the brittle.

I like all three materials quite a bit, and plan on getting some more of the Butter-board and 60# NC Proofboard soon for both business and hobby use.

Tooling
The rough cuts were done with a 1/8" 2 flute square end mill, the finishing cuts were done with a 1/16" 2 flute ball nose end mill. Both bits were purchased from IMService, at nice prices and the bits are very good. I was concerned that I may want to use single-flute bits, but these bits performed admirably with these materials. At some point I'll try a future cut with single-flute bits for comparison's sake, but these bits cut well, showed no propensity for clogging. They stayed sharp and cool through the cuts.

CAM Software
As to Cut3D, I'm quite happy with it so far, and I'm planning two more jobs for it in the immediate future. I'm also going to be giving MeshCAM a spin for a high relief piece of work in the near future, and I'll be reporting on that soon.

CNC with Vectric's Cut3D: It's Great, I'm So-So

2011-09-20T14:10:00.000-07:00

After running through a bunch of free CAM software that didn't do what I wanted, I finally ended up where I pretty well knew I was going to end up. I downloaded a trial version of Vectric's Cut3D software.

I also happened to have some samples of machinable urethane plastics to try out, and the new software was just the thing to do that with.

I started with one of Vectric's sample files, the rooster statue. The statue is initially scaled to stand twelve inches tall. My material was about 3.5 by 2.4 by 0.9 inches in size. So I used Cut3D to scale the object, no problemo.

I positioned it in the block, added some tabs, again no problem.

Since this was my first time using Cut3D, my only concern as I went through the simple linear process of setting things up was what I would end up with in the way of files at the end. Would I get a file with some sort of pauses in it, during which I would do tool changes and material flips (to machine top and bottom), or would I have to edit these in, or what?

As it turned out, Cut3D produced four gcode files. Top rough cut, top finish cut, bottom rough cut, and bottom finish cut. For machines with tool changers, it can consolidate the files that have tool changes between them.

So this makes it easy. Load up the material, align the machine, run the rough cut for the side you start with, and wait for it to complete. Then change tools, recheck alignment, run the finish cut for that side. When that's over, flip the material, put in the correct bit for roughing, align, and run the other side's rough cut file. When that's complete, change bits and check alignment one last time then do the finish cut on the second side. Voila, you're done!

When machining a part on more than two sides, I presume that there are more files.

Well, Cut3D worked great. I didn't have the recommended post-processor file for my setup, but the Sherline inches was close enough so I tried that. I got the recommended post-processor for my setup from Vectric's support in my email today. The Sherline gcode worked fine, however.

The only thing that didn't work was me.

Here's my CNC setup. Here's what I got:

Front Side, so far so good...

Back side. Whoops! It's Upside-Down!

Everything started out fine, but I let myself get distracted by some visitors when I went to do the back side cut. I got the alignment right, but had it upside-down from the orientation I should have had it.

Moral of the story: put unambiguous markings on your workpiece to avoid mistakes during machining, and if a distraction gets introduced, set the work aside until it's gone. ;)

The material I'm machining out of is one of the denser varieties of NC Proofboard from Golden West Manufacturing. They're a short way away from me, and this was the first sample piece of their materials I've machined. And it machines like a dream! I may never machine wood again. Well, wood is awfully pretty so I'm sure I will, but not unless I really have to.

Their materials deserve their own article, so I'll be writing more about them once I've tried out a few more of my samples.

Upshot, Cut3D is a great program, and the price is great. I'm looking forward to doing a bunch of work with it, and possible upgrading to VCarve Pro some time later when I feel the need for more flexibility.

Motorola 68000 "Art"

2011-09-05T00:06:00.001-07:00

I got an email message today about an image I posted some long time ago of a poster for the Motorola 68000 processor. The original image is a black and white test of image detail with my then-new cell phone.

Well, looking back at that old image is downright embarrassing. So here's a better one, and some other M68000-related images to go with it.

My poster from the Wescon conference after the 68000 was introduced. It came with a 68000 die tacky-glued to the poster, which I've since misplaced.

The M68K Family User's Manual. Hardware Design Stuff.

The older user's manual just for the 68000, this one's programming info.

Another 68000 User's Manual, from HP, pretty much the same as the above, but smaller and with an HP label on.

The Pascal Cross Compiler's Manual for the 68000

This is the front of a pre-release M68000 data sheet I got at a promo event in 1979. It got me pretty excited, I can tell you!

Cover of the software book that goes with the 68K family hardware book, above.

The Entire Traveller RPG on One CD

2011-08-03T21:27:00.000-07:00

Traveller is a science fiction RPG that appeared in 1977. Supplements and add-ons for this game appeared for another 6 years or so until a new version, MegaTraveller, appeared. Other versions have followed, with the most recent being Traveller from Mongoose Publishing.

The original game (PDF of contents) is now available from Far Future Enterprises, the company of Marc Miller, the original author of the game. It has several different editions of the core game rules, all the supplements, add-ons, and tie-in board games from the original publisher.

I originally bought the game in print form shortly after its appearance in 1977. I bought the first version of the Classic Traveller CD about 3 years ago. It was a tremendous resource, but it had some flaws. Now a new version of the CD has been released.

It's a huge improvement over the original CD. It contains additional versions of the rules that were not included on the first CD. Errors and poor scans have been corrected. For example, the book Scouts was poorly scanned on the old CT CD:

The New Traveller CD Has Cleaner Scans. New CD Above, Old Below. New scan is sharper and has higher resolution.

New Traveller CD Character Recognition:

CHARACTER GENERATION
A character is initially generated by rolling 2D for each of the six personal
characteristics: strength, dexterity, endurance, intelligence, education, and social
standing. This initial step is identical to that for standard character generation.
College: Any individual has the opportunity to attempt to obtain a college education.
In the Scout Service, a college education is generally necessary for an individual
to secure assignment to the Bureaucracy.
Any character may apply for admission to a college. The admission throw determines
if the character is admitted and actually starts attending college; if the throw
is not achieved, the character remains age 18 and may then directly attempt to
enlist in the Scouts. Once admitted to college, the individual determines his or her
success in college for the full four years; if the success throw is not achieved, the
individual has aged one year (to age 19)

Old Traveller CD Character Recognition:

CHARACTER GENERATION
A character is initially generated by rolling 20 for each of the six personal
characteri~t8cs: strength, dexterity, endurance, intelligence, education, and social
standrng Tnos notla step s dsntical to that for sranasrd character genera! on.
C0I.g.: Any lnaivlobal has Ine op~ortunry la attempt to obra n s col sgs ed-eation
n tna Scnn Servlcs. a col eoe sa~cation:o "oeners l.v neceo osrv for an me v d ~ a l
to secure assignment to the Bureaucracy.
Any character may apply for admission to a college. The admission throw determine8
if the character is admitted and actually starts anendlng college; 8f the throw
is not achieved, the character remains age 18 and may then directly attempt to
enlist ~n the Scouts. Once admitted to college, tha individual determines hieor her
SUCCBSD ~n cdlege for the full four years; if the success throw is not achieved, the
indlvldual has aged one year Ito age 191

Missing pages and other problems have been fixed.

If you're looking for the best value in RPGs, check this out.

More Traveller RPG Than You Can Fit in a Low Berth

2011-07-20T13:48:00.000-07:00

In the 1970s I regularly shopped at a local militaria/war game shop in Walnut Creek, CA called The Centurion. In 1977 they had a new game, called Traveller. When I bought it, the guy at the shop commented "I thought of you when I ordered this one. You're the first one to get it, let me know what you think of it." I was a sucker for anything in the way of science fiction games, so he had me tagged. If there was a blurry mimeograph in a ziplock bag with a spaceship on it, I'd buy it.

I still have the game today:

My original Traveller game from 1977

What's inside the box.

Needless to say, I like the game. A lot. For lots of reasons.

Fast Forward to 2007
Then, about three and a half years ago, I found out that Traveller had become available on CD. Not just the original game that I owned, but all the expansions that had been offered by its publisher, Game Designer's Workshop.

The Classic Traveller CD and the JTAS Magazine CD

All the expansions means:

All the additional rule books.
All the scenario, campaign, and adventure books.
The several board games related to the game.
The later editions of the rules.
Etc., etc.

In other words, a HEAP of stuff to read and enjoy.

As you can see from the picture above, I also bought another CD with it. That one contains the magazine "Journal of the Traveller's Aid Society", the magazine for the game. What a treasure trove of gaming stuff!

Fast Forward to TODAY
The Classic Traveller CD got an update earlier this year. It's got more versions of the rules, corrected and improved scans of some of the material from the new CD, and so on. For those that purchased the original CD, the new one costs only $7.

Unless you order an additional CD when you order the update. In that case, the $7 cost of the update CD is refunded. Since there are many different CDs for many different editions of Traveller available from Far Future Enterprises, it wasn't going to be hard for me to take advantage of that offer!

But Wait, There's More!

Not only that, but there's a special sale going on called 443. Buy three CDs and the fourth is free (thus Four for Three: 443), four for the price of three. Since two more CDs of "Classic" Traveller material were out, I was halfway there already. Add to that the CD of the latest version of Traveller, still under development (Traveller 5), and the forthcoming Traveller 4 CD (I have the core book for this version, but not some of the other books I've seen widely touted by other players on the web, which will be on this CD), and I'm good.

Today the mail held this:

My Amazing New Traveller CDs. One more will arrive after it becomes available at the end of August.

The T4 CD was a pre-order, so it's not in the picture. It'll be here soon enough. I've got plenty to keep me occupied until it arrives!

Here's the new Classic Traveller CD:

Bling! The new CT CD. Not just an amazing game collection, it also makes a great diffraction grating! Read the books as you use it to analyze spectra of far off stars!

Duke Norris has my back. There's nothing like having the nobility of the Third Imperium of Man keeping an eye out for your data. Beats counting on some drunken X-Boat driver to get it to you.

CNC Projects: 10 Basic Rules I've Learned

2011-07-12T16:26:00.000-07:00

Here are some basic rules I use when selecting or setting up CNC projects. Let me know your rules, or any tweaks you see to mine. Thanks!

1. Don't make anything that you can buy easily, unless you have some specific reason that over-rides the extra cost, effort, and likely unforeseen problems.

2. Remove as little material as possible. Look carefully at item placement in your material stock, different ways of cutting the piece, possible design changes, etc. to reduce the amount of cutting and the amount of material to be removed.

3. Plan your cuts so that the ones that most depend on the accuracy of the bit's size are done with a fresh bit. Bits wear while cutting, if you're planning on cutting, say, a 1/4" dado with a 1/4" bit, you should do it while the bit still has a 1/4" diameter to minimize post-machining to make things accurate.

4. Test your ideas in scrap material first, unless it's a minor variation on something you've already done. Chances are you'll either find a problem you didn't anticipate, or figure out a way to do it better on the next go.

5. Be fanatical about your means of mounting the work. The accuracy and success of the machining relies on it, so think about this as much as you think about the rest of the project.

6. Once you find something that works, build on it. Once you've developed a routine for mounting, cutting, registering, or whatever that regularly produces the results you want, keep doing it. It helps to take notes and pictures for reminders in case there's a break in operations that leaves you a bit rusty on how you did it before.

7. If something isn't working quite, don't keep tolerating it. Fix it, replace it, find another way. It'll be worth the time saved later.

8. Learn from others. Watch videos online, visit other folks' websites, visit with other CNC machinists, see how it's done with different machines or in different areas than your individual interests.

9. Do "science" projects. Plan and develop projects just for the sake of trying out something new or exercising a different procedure. Just like doing a first work in scrap, they'll save you time in the end.

10. Make one complete finished item before you cut out a whole set of parts production-line style. While it costs a fair bit of time in setup to go through once for the prototype, then go back and start over for production, it's better than finding out you've got a stack of parts that won't work when you get to final assembly.

My CNC Website

microCarve CNC Project: Collectable Spoon Rack

2011-06-20T21:26:00.000-07:00

Here's the initial results of my spoon rack projects as mentioned in prior posts:

My Spoon Rack Project Idea

Decorative Motifs for the Spoon Rack

Here's the first one:

I have parts for 3 cut out. There's a bit of manual finish work yet to do for the remaining ones. The weather has turned hot and dry, which is good for the staining work.

Decorative Motifs in GCode for CNC

2011-06-07T17:26:00.000-07:00

My manual gcode workflow is getting better. Until I'm in a position to pick up some commercial CAM software (probably early fall later this year), I'm getting by with manual processes. It's not too bad, the fact is there's still a lot I'm learning about machining while I work. The lack of software doesn't mean lack of projects at this point.

I have a much better idea of how things are going to turn out when I design them now, so I'm not wasting nearly as much time designing things that aren't going to work out when I make them now. Here are my latest test cuts:

Testing the motifs with different depths of cut.

These are some decorative motifs for my spoon rack project. My first drawings were of designs that were far too involved for this project's scale. This set, above, turned out pretty much exactly as I drew them on the green engineering paper. In these tests I was trying out different depths of cut (set using variables in the gcode.)

The first fully complete and ready for public viewing spoon rack should be done soon. I've been going back and forth between different elements of the project, touching things up and trying to get the different parts all in sync, not only in mechanical properties but also in the coding standards I use for the files. I'm intending to publish this as a project on my website once it's done.

My present workflow goes something like this:

Come up with idea.

Draw it out on green engineering pad.

Lay out dimensions on drawing relative to a selected origin for the piece.

Open up EMC2 and a text editor.

Write out gcode in the text editor, checking the work in EMC2's preview often.

Transfer the file that looks good on my editing system to the CNC controller.

Check dimensions and movement manually before loading a workpiece on the machine.

Do an "air cut" of the file.

Put some scrapwood on the CNC. Check level and positioning.

Check origins and movement limits again.

Do a test cut.

Go back and make any design changes and repeat the test cut, if req'd.

Cut the real thing. Repeat as necessary.

At this point I'd say that the guesswork that happens throughout this process is far, far less than it was even a week ago. That means I can do stuff faster. I also added a wireless router to my CNC controller computer's setup so that I can get files there from my design system in the house faster and easier, as well as do edits to the original files there rather than ending up with version control madness.

I'm also getting much better at mounting up work in the machine accurately, and in checking movement and dimensions on the machine before I start a cut. This also means the work goes faster. Which means I can make more test cuts, and still have time to make more finished pieces.

Mount an HF Router on Your CNC, Quick and Easy

2011-05-26T17:46:00.000-07:00

I posted my design for mounting the inexpensive Harbor Freight 1/4" trim router #44914 to a CNC on my website today. I've posted a dimensional drawing of the base plate, and given instructions for the rest (it's bone-simple, really!) Click the pic below to go right to it:

My GCode Gets a Bit Tricker: Working with the microCarve A4 CNC

2011-05-24T20:21:00.000-07:00

We collect souvenir spoons when we travel. Unfortunately, we overflowed the little wooden rack that holds our spoons several years ago:

We have almost twice as many little spoons as will fit on the rack. So I decided that a good CNC project would be making some additional racks that will hold the additional spoons, plus any extras we acquire in the near future.

Building the Toolchain

I've been using this project as a sort of pilot for putting together an automated toolchain for my CNC. You know, draw the object in CAD, convert it to gcode, and cut on the CNC. In the past I've just used image maps as depth maps and hand-written gcode to produce things. This project seemed to have about the right level of complexity for an initial project with a new set of tools.

At first, I had already designed the rack for the spoons themselves by hand on paper, and written gcode to match. But I laid this aside and tried out several CAD tools. The CAD tool that I ended up with a decent file from in the least time was Google Sketchup, running on my Mac. Unfortunately, Sketchup doesn't write in the CAM-friendly file formats. So I pulled MeshLab, which converted a Sketchup Collabra file to STL for CAM.

Close-Up of the Item that Inspired my Project

The next step was CAM. After spending over a week trying out different free CAD packages (see below for why I'm starting with no-cost software), I was getting antsy to start cutting something. After three goes with different CAM packages on three OSes, and still no results worth cutting, I just decided to pull out the gcode and give it a once-over.

GCode FTW

I did a quick third pass over my gcode program on paper, then typed it in on my EMC2 system with gedit. The EMC2 preview was, as always, very helpful. It let me catch a bogus Z-value. Once that was fixed, I plunked down a piece of MDF for the trial run and let 'er rip.

My first go at the spoon rack's shelf, the back is another piece. But I've got an idea for improving on this...

The piece cut out very nicely. I ran it in three passes, the support for the piece was pretty minimal, so you can see where each pass cut across. A bit of sandpaper would fix this well enough.

However, I think I'd rather do the little shelf out of 1/4" stock. I used 1/2" because my prototype uses that thickness. But it's not like there's a lot of stress on the part from the spoons. So I'm going to re-build my code for a 1/4" thick piece before making the "production" units (probably three of them.) Then I may try to use the automated toolchain again for the backs of the spoon racks (all I have in gcode at this point is the little shelf.)

Why Free?
I don't have any aversion to spending money for quality software. In fact, much the opposite. However, I've already spent the money I had budgeted for the CNC. Plus I've tread on my money set aside for travel this summer because of some unexpected household expenses.

For the time being, I'm being a bit hairshirt when it comes to software.

I'm very happy with EMC2 for my CNC software at this point.

Sketchup is pretty well doing OK for me for CAD right now, though there are things I will want to do later that I'm not sure it does easily or well. When money permits, what I'd really like to do is pick up ZBrush. Hopefully within a year or so. Sooner if possible.

For CAM, I'm thinking that I'll want to pick up something like Cut3D from Vectric. It seems to have the functions I want. Cut2D is a possibility, too. I'll be doing the free trial on each in the not-too-distant future.

In the meanwhile, if you know of some free CAM software that doesn't just treat an STL object as something to be rastered over, drop me a note. I'm completely OS-agnostic. Most recently I was doing CAD in MacOS, running CAM (FreeMill, a good package but didn't do what I needed) on Windows, and I'm driving the CNC with EMC2 on Linux.

microCarve A4 CNC Assembly Instructions Online

2011-05-20T13:35:00.000-07:00

I've posted step by step instructions of how I assembled my microCarve A4 CNC router on my website:

microCarve A4 Assembly

This is the first component of a new section of my site dedicated to CNC machining. Since I've gotten the A4, I've really enjoyed spending a lot of time working with it, learning what I can do with it. I'm still a long way away from solidly competent, but it's a state I'm enjoying working toward. And the stuff I'm making along the way is fun, too.

So, as time allows, I'll be expanding the content I have from the CNC Machining home page on my site to include project info, tips and tricks I learn along the way, and links to information from others that I've found especially helpful (if I linked everything that was helpful to me, it'd overwhelm me entirely!)

Fundraising with my microCarve A4 CNC

2011-05-16T15:01:00.000-07:00

This last weekend, my daughters went to a special SacAnime Con. It was a Japan Disaster Relief con, which raised $6556. My daughters had some space on a vendor table at the con, and last week they asked me of I could make something that they could sell to raise money for disaster relief.

I set aside my other projects, and turned out a number of little "remembrance tablets", as you see in the pictures here. The idea was that for each one we sell, we'd pass on the profits to Second Harvest Japan, Japan's first food bank. We think they do great work, whether there's been a disaster or not. So it seemed like a good cause to support.

The tablets are about 1.5 by 2.25 inches (~3.7 x 6 cm), hung on a cord so to be worn around the neck. Each design is bilingual, English and Japanese. I took a bit of a liberty with the "Prosper" tablets, the Japanese is more properly "Prosperity" but the English word was too long to fit on the tablet with the level of detail I'm able to carve at present.

This tablet is larger than the others, measuring 2 x 3.5 inches (5 by 9 cm). The detail is far more striking in person than in this photo where the light from overhead washes it out.

There were some other designs that I'll try to get decent photos of soon.

Unfortunately, we weren't able to sell all of these tablets, I still have many left. If you're interested, drop me an email. I have instances of all the above plus a couple of other designs available. And it'll still benefit Japan--that's what these were made for.

Making the Tohoku Remembrances

These were made using the image-to-gcode converter included with EMC2. It's got some serious quirks to its behavior I had to overcome. When I originally set out to make these, I had two ways I could do it. I considered writing my own gcode programs by hand, and using the image converter.

I decided to go with the image converter because I thought it would allow me to make more different designs faster than writing my own programs by hand. Unfortunately, I was wrong. The time I spent learning the quirks of the image converter, with what sort of feature depth I would get, how much of a border around the image, and so on was far, far more than I expected. It would have been far more productive to hand-code the simple designs I ended up with.

My original ideas were more involved, more like the "Tsunami of Love" design, above, which was carved last of all at about midnight before the con. On each iteration I ended up simplifying my designs while trying to get the sort of features I wanted in the carving. I wanted to have the Kanji characters carved into the wood, originally, but I couldn't control the way the software managed the depth and width of the lines when doing this. The Kanji would end up barely visible, and the English characters were unreadable.

A CNC Success, in a Way
I took advantage of this project as an initial test of my ability to do some small-scale production with my new CNC. As a fundraiser, I have to say it didn't work out so well, but as a first go at some small-scale, simple production it was a success--barely.

My decision to rely on someone else's software that I don't entirely understand was a real weak point, but I still managed to turn out a decent number of pieces of work before the con. The investment of time into each one was over double what I originally expected. Still, I got them done within the time margin I provided for this project. Barely.

I'm happy with the results, particularly the Tsunami of Love item, and think I could go on to make some better stuff. Though I clearly need to work on my toolchain. In the future I need to have a tool at hand that I'm familiar with that will produce better results than the free image-to-gcode converter. And I need to have something that's more powerful than hand-written gcode programs for all but the simplest designs.

I've learned a lot over the past week, both about myself and my CNC machine. Now I'm ready for the next step.

What I Learned with My CNC Machine Today

2011-05-06T17:10:00.000-07:00

I'm in the second day of a one day project today. Hopefully I'll finish it on Day 3.

But, at each step I'm learning new and useful things.

Yesterday I learned:

There's a point where you need to stop writing gcode by hand, and use CAD/CAM.

Doing tool compensation by hand is a real bear.

Don't think of designs that are too much more elaborate than what you've actually made before.

Today's Lessons:

When your test piece is MDF and your work piece is real wood, there are going to be differences.

Grain and cutting direction matter more when using a CNC than when you route by hand, where you make all sorts of little compensations that you don't even notice.

Just because this piece looks like the last piece you cut doesn't mean that it really is, even if it's a piece off the same stock. This can be really important when you're clamping your work down.

Nonetheless, I managed to avoid anything worse than some minor marring of the surface of one work piece. It's still usable for the project.

So far, I've succeeded at using the CNC as a really complicated and finicky power planer. Unlike the first time I used a power planer, it did not throw a piece of wood across the shop at barely subsonic velocities. One piece came a bit loose in the clamp is all. I shut down the machine in time, re-clamped it, and picked up where I left off.

First Attempt at Engraving an IC with my CNC

2011-05-04T17:39:00.000-07:00

I decided to try doing a smaller, more precise job with my microCarve A4 CNC today. I took some of my GCode program from yesterday, scaled it down (fortunately I provided variables to do all that automatically for me) and added a chip number in characters that I hoped would show with the bit I'm using.

Here's what I got:

My first shot at engraving an IC top. It's not really an 8085 microprocessor, it's a dead ROM I happened to have hanging around.

The cut widths are about 35 thousandths. Too large for the level of detail in the smaller key pattern. The single large key above is scaled three times larger than the smaller keys. The base leg length for the small keys (the smallest segment size) is 25 thousandths. So it's easy to see why it didn't quite come out.

Still, the accuracy would have been plenty good, if I'd had a sharp enough bit.

Onward and upward! :)

Learning GCode with EMC2

2011-05-04T09:47:00.000-07:00

I'm spending a lot of time with my new microCarve A4 CNC router this week. My first couple of items were made using a handy image to gcode converter that's built into the EMC2 control software I'm using.

But the image converter simply treats the image as a depth map which is cut by raster-scanning with the cutting head. For the designs I used, this was slow, and produced rougher results than would be produced using vector cuts.

So I looked at a couple of approaches to improve things. One is using CAD software that works well with a CAM package to covert the CAD design into machine control instructions to cut out the CAD shapes. The other is to go straight to writing my own machine control programs by hand. I know that I'll want to have both methods in my toolkit, but which to use first?

After a bit of back and forth yesterday morning, I decided to start with programming by hand first. So I dove into the EMC2 documentation for gcode, the programming language more properly called RS-274-NGC. What a catchy name, eh? You can bet that the folks who picked programming language names like "python" and "Java" are kicking themselves after seeing how "RS-274-NGC" rolls off the tongue.

Results of My First GCode Program.

Well, the EMC2 site has a link for a gcode tutorial, but what's there is...not much. Maybe I'll pitch in, since that's what wikis are for, right? The I went an read the EMC2 documentation, which has the standard cart-before-horse format of discussing details before generalities. Then I found the excellent LumenLabs GCode Tutorial. Much better!

I read some bits, scanned others, then hit the keyboard on my CNC control system. It's an old Athlon 800 with 768MB of RAM loaded up with the EMC2 LiveCD install for Ubuntu Hardy Heron, with EMC2 upgraded to the current version after install.

I fired up EMC2 with the SIM-Axis configuration for developing the gcode. I've got three different configurations of EMC2 on my desktop. I've got the SIM-Axis setup, and two different configurations for my microCarve A4, each with different origins for the axes.

I used gedit to create an initial gcode file, then opened it in EMC2. The gcode preview window is great. Whenever I edited the gcode file and saved, I'd click the reload button in EMC2 and immediately see the changes. Likewise, the error messages were good enough to let me find my problems, though the problems were usually typos rather than what was reported.

I used iterative development, of course. No sense writing too much code before finding out that I didn't understand some element of syntax. I started with initializing the mode settings, lifting the head to a safe traversal height, traversing to a point in space, then returning to machine zero. After fixing a couple of problems, I got what I wanted. Then I added a few additional move commands, and got the simulated CNC to follow them. At that point I could see that things would get out of hand pretty quick if I didn't learn some basic flow control.

So I read up on subroutines in gcode. I laid out a simple key pattern on graph paper, and wrote the necessary routines. That's the border you see in the picture above. That was the easy part. It's all straight lines.

Next was curves. I read up on G2 and G3. I hadn't thought about the ability to shift the depth of cut across the curve when I started reading, but by the time I was done I was thinking, "Hmmm, if I vary the depth of the cut with a V groove bit, I can vary the width of the cut just as I would vary the width of a line with a calligraphy pen."

So I broke out a fresh sheet of graph paper, and started drawing some letters. Well, it took me about three times as long to lay out the letters as it took me to lay out the key pattern, but I managed that. Not only that, but I set things up with scaling factors and variable settings that allow me to easily scale and move the letters.

Results
The results you see above are what I got from the first "live" run of my first gcode program. The cuts are a bit deeper than I'd like, and the 90 degree bit I'm using right now doesn't help. Also, the cutting was a bit fast for the plywood, causing the wood to be frayed on the cross-grain cuts. Still, the varying of "line weight" on the letters turned out well. Overall I'm happy with it, and the defects should be easy to fix when I run it again. I'm planning on building a complete alphabet for this font and throwing it into a file for later use.

microCarve A4 CNC First Cut Complete!

2011-05-02T13:23:00.000-07:00

I got a router mounted on my microCarve A4 CNC machine this weekend. The router I'm using is an inexpensive 1/4" router from Harbor Freight. It's mounted on a base plate I made out of 3/4" plywood with a pair of muffler clamps holding the body of the router:

I've got two bands wrapped around the body of the router cut out of a bicycle inner tube. They help mate up the muffler clamps to the router body. I was expecting to drill and tap a hole into the router for a screw through the base plate, but with the rubber straps everything is very firm and tight.

Today I spent some time "cutting air" to make sure the tool would run properly before I put a bit in. I had to invert the Z and Y axes in the setup I was using as it turned out. Then I tested twice more, once again with no bit or wood, then again with a bit and wood in the machine, but the Z axis set high enough the bit of the router wouldn't quite reach the wood.

Everything looked good, so I made my first cut:

The material is some plywood I recovered from an old failed project. As you can see, it wasn't mounted completely flat. The top piece is held by some screws that hold it from underneath.

The G-Code was a raster pattern generated by an image-to-gcode converter that comes with the EMC2 software I'm using. That's why the bottoms of the letters look kinda scrappy, if they'd been cut continuously rather than raster-cut, they'd probably look a lot better.

The bit I used is a 1/2" 90 degree bit, I don't have any really nice bits yet. Now that I've got the machine actually cutting things out, I can work on refinements.

The depth of cut is 1/8".

Now I'm looking forward to getting some better bits, getting my CAM software in order, and so on.

Edit:

Had one more go with what I've got on hand this afternoon. It's a little more ambitious. Here you go:

8085 Microprocessor Reference Card Posted

2011-04-22T06:12:00.000-07:00

I put up a downloadable PDF of my own 8085 reference card on my website:
8085 Microprocessor Reference Card

I've added a bunch of information that I often use that's not on the original Intel reference card. This includes the undocumented 8085 instructions, timing for all instructions in T-States, a pinout and basic electrical reference, and a little more detail on the additional interrupts the 8085 adds to the 8080A design. Such as the fact that they're off by default, which I've forgotten at least a couple of times when writing test routines.

The card is laid out so that it can be printed on either a single-sided sheet or double sided to make two cards laid out with a front and back. The finished card looks great on a good cover stock paper, and folds to fit nicely into a pocket.

microCarve A4 CNC Assembly Complete!

2011-04-08T23:53:00.000-07:00

I finished my motor controller box day before yesterday, as described in Gecko G540 Power Up! as I build my microCarve A4 CNC router. Just take a look at the past several articles in my archive for more background and pictures of the A4.

Completed Controller Box with Improved Fan Cutouts

Front with Big Red Switch and Power Light. Needs personalized stickers.

Completed MicroCarve A4 without Motors.

Completed MicroCarve A4 CNC with stepper motors in place.

Tomorrow I start testing without a spindle. If all goes well, I'll start assembling a spindle mount.

More at: my CNCZone Build Thread

Gecko G540 Power-Up!

2011-04-04T21:59:00.000-07:00

I finished the enclosure for the power supply and Gecko motor controller today!

I changed my fan layout a bit. I put all four fans to work at the back of the box. Two are intake fans, the ones on the opposite side are outlet fans. They blow across the back of the Gecko. They make a pretty good stream of air. The fans are all the same type now, unlike yesterday's picture. They're all the larger variety of CPU fan. 75mm or thereabouts.

I used CPU fans for their low profile, I've only got about 3/8" clearance on each side of the inside. I've paired them up side by side to increase airflow.

This also meant adding a pair of fan cutouts to the back end of the box. So that was added work over what I'd anticipated.

Nevertheless, I got the holes cut, the fans mounted, wired, and a connector on them with a mating connector on the power supply.

I wrangled the wires and got the box closed. I had the Gecko pulled (I'd taken it out after the initial test fit. I pulled the power leads for the Gecko out of the box and hooked them up to the Gecko.

When I plugged in and powered on, I got Power and Fault lights (there's still no E-Stop wired to the Gecko, just power at this point.) That's a good test.

Off to bed for me. Pics tomorrow.

MicroCarve A4 CNC Build Progress: Driver Enclosure

2011-04-03T23:03:00.000-07:00

I'm getting closer to having a working CNC mill. I've been taking long as necessary to get the job done right the first time as much as possible, and to put on some polish at the outset.

My current work is to convert an old UPS into the power supply and motor driver enclosure for my CNC mill.

I started with this:

And cut the back panel to hold my Gecko G540 motor controller like this:

I go into more detail on these steps in an earlier article.

One of the problems with this enclosure is the airflow. I want to make sure there's plenty of it for the current electronics. I got another metal nibbler and made some cut outs this morning for the power supply:

I didn't worry about cosmetics here, I just wanted to get on with the job. As long as I won't cut myself, I don't care how the cutouts look.

You can see that the cutouts line up well with the power supply vents.

There's room for some airflow around the power supply inside the cabinet.

I wanted to take advantage of the big red power switch the original UPS had, so I chopped of the section of the original PCB with the switch, then mounted it on the original mounting hardware with some minor mods to make it stay in place without the rest of the board.

The original switch's specs are good enough to wire it directly into the AC power line for the new circuit.

I thought I might have to use the switch to pull a relay on the AC line for the power supply, but as it turns out it's adequate for passing the AC directly. Whew! That saved some work.

Finished AC Wiring

Power On, Looking Good!

Then I wanted to have a power indication LED. I made up a resistor divider both to feed a lower voltage to the LED than the power supply's 48V nominal output, and to limit current to the LED. I planned on 6V at about 10mA, and made a divider. The original two-color LED didn't light up very bright at 10mA (I should have built the divider for 20mA), so I put in a red LED that's daylight visible at 10mA.

The divider/current limiter.

The new red LED, held up to the light pipe with shrink wrap so I can see how bright it'll be. I later removed the unshrunken shrink wrap, hot-glued the LED to the PCB, and it fits up to the light pipe inside the cabinet perfectly.

My last item on this cabinet will be finished tomorrow. Since the power supply puts out 48V and all my available fans are 12V, I put four fans in series. I'll have two fans drawing air in from the sides of the cabinet across the back of the G540. A third fan will exhaust air out the front of the cabinet. The fourth will try to stay out of the way. I marked out a place for the last fan to draw air into the cabinet from below the Gecko, but didn't cut it. If it gets warm inside the case while I'm testing it with motors attached and driving a CNC table around, I'll put in the hole for the fourth fan.

The fans, and an enlarged air vent for one of the fans in the side of the cabinet cover.

When I'm not working out in the shop, I'm personalizing my microCarve A4's paint job a little:

Microcarve A4 CNC Build-Up Progress:Controls

2011-04-01T13:09:00.000-07:00

I'm the proud new owner of a microCarve A4 CNC machine. I'm still getting it built up--I got my motors and motor driver three days ago and the A4 just arrived yesterday.

Yesterday and today I was working on an enclosure for my Gecko G540 driver and the power supply for it and the motors. After looking around at what I had on hand, I decided to "repurpose" an old UPS's enclosure:

The Enclosure, after the guts were removed.

The original back plate.

And the Inside

A Fused Mains Plug--Very Handy!

Here's where the Gecko will fit, more or less.

My original plan was just to use a nibbler, starting at the hole for the phone jack for the UPS. I scribed my cut lines, then started cutting with the nibbler. About an inch into the work, the nibbler broke. Did I mention that I'd modified this nibbler in the past to cut plastic? I made it so that its jaw would open wider. This weakened the nibbler a bit, but hey, who needs strength for cutting plastic?

Then I went and cut some metal with it. It wasn't up to that job any more.

I spent much of the day yesterday trying to buy a new nibbler. I went to five different places nearby. Four of those places had never heard of a nibbler, at least three seemed to think I was making it up. The last had heard of nibblers, but they didn't have any.

So I came back home and got to work with other tools. I finished the job about noon today. It was a lot more work, but the results are decent, even if they're not quite as clean as I can get with a nibbler. Plus it made a lot of steel filings. Dremel, cutoff wheels, cold chisel, files, grinding stone and hammer were among the tools used.

The Gecko, in its new home.

The Gecko from the back.

Since I had to take care of all those filings, I did a pretty thorough cleaning of my bench so that I'd have a place to assemble the A4 without any further delays. My next image reveals wood which seldom sees the light of day:

The top of my bench. Stains are just Tapmatic fluid that hasn't dried yet.

It looks like it's outside because of the window. In fact, it's in a second garage that was added outside the house's original garage. The original garage's windows were just left in place when the prior owners added the second garage.

A Look at the Microcarve A4 CNC

2011-03-29T18:48:00.000-07:00

My Microcarve A4 CNC is on its way! John shipped it this morning.

Here's what it looks like:

Over-all view

X Axis Motor Mount at Left

Y Axis Motor Mount in Foreground

Z-Axis. Beautiful, isn't it?

Its Unpainted Twin. A bit more detail visible.

Logo shows nicely here.

I'm getting ready for its arrival by putting together the electronics. I'm modifying an old UPS cabinet for the motor drivers and power supply. Pics soon.

CNC Machine: Microcarve A4

2011-03-28T00:58:00.000-07:00

I've been looking at setting up my own CNC machine for about ten years now. I've worked with CNC and CMM machines off and on since the early 80s. I remember hooking up a CP/M computer to a CMM machine, wowing the lab with its ability to automatically record measurements then produce a compliance report on each part as it was inspected. The next day we went back to doing it manually. Everyone was impressed, but they weren't prepared to add computer infrastructure to the lab at that point.

In my case, I wasn't looking to add supporting a CNC machine to my workload before now. Whenever I read the online forums for adding computer control to milling machines, or building up simple hobbyist CNCs, it looked like working on the CNC itself became the prime object of the effort, rather than using the low-cost CNC for production.

There are a lot of bits and pieces to a CNC. There's also a lot of work represented by the physical machine's construction. I'm aware of this from the professional CNCs I've seen at work. They're high precision equipment, with a team of skilled people supporting their operation. Like a machinist, a machinist's assistant, an electronics tech, a programmer at least part time, and a metrology tech or two checking up on it periodically.

As a hobbyist, I have to do bits of all their jobs, plus the jobs of the design engineers, manufacturing engineers, materials engineers, and their technicians to produce things with a home CNC. Needless to say, I won't be trying to do quite the same thing.

I've started by purchasing an existing CNC machine bed rather than trying to design and build my own. I'm also purchasing a commercial motor controller system. My engineer ego is not in the least bit challenged. My engineer superego knows well the tremendous value of the design work that's gone into the pieces. Cookbook integration is good enough for me here. It's the stuff I make with it that I'll set my ego loose on.

The machine I've purchased is a Microcarve A4. The designer did the commercial Fireball V90 previously. The Microcarve A4 is a smaller unit built for high precision. Which suits me perfectly--a specialized machine is just what I'm looking for.

The controller I've purchased is the Gecko 540. It looks like a well integrated unit with a lot of design fine-tuning in it.

Both should arrive soon, the controller (driver in CNC terms) may come tomorrow if the USPS package tracker is telling me what I think it is. I've got a computer running EMC2 that I've been learning how to use to some degree, that I'll hook up the Gecko and motors to once they're here to shake out that element.

I've got some decent software for 2.5 dimensional conversion of images and such (including the image to gcode software included with EMC2), I'm still trying out CAD packages for real 3D work and CAM programs for converting those designs to tool control instructions on the CNC machine. I want to get that all shaken out to make for as little obstruction between idea and finished part as possible.

It'll be an exciting next couple of weeks. I'm looking forward to getting things assembled, functional, calibrated, and churning out parts. With breaks for infrastructure work (like dust/chip collection and an enclosure) between production runs..

Don't Let La-Z-Boy Re-Pad Your Chair

2011-03-20T18:01:00.000-07:00

My spring break project this week has been redoing the padding on my easy chair. I've got a great big La-Z-Boy that I bought about 10 years ago. The padding on the seat and the lower back needed to be refreshed and the time off from teaching this week gave me a chance to do it.

This Time, I'll Do It

Normally, upholstering is not something I look to do as a pastime. But, some time ago, I made the mistake of taking it to the La-Z-Boy factory to get the job done. The chair is one with ten massage motors built in. I often get tears in my back muscles, those motors are really important to me. When the chair went in to the La-Z-Boy shop, all ten motors were working fine.

When it came out, only two at the top of the back worked, the two most useless motors (from my perspective) in the chair. None of the others functioned. Needless to say I was pretty upset. La-Z-Boy not only couldn't account for the problem, but refused to do anything about it. It wasn't part of the service, apparently, to make sure your chair wasn't damaged in the course of repadding.

Not only that, but the new padding job was pretty lousy. It was only a couple of weeks before the seat was mashing in again. Plus, everywhere they had lifted up the upholstery there were now lots of sharp little staple heads. Before the heads had either been placed better, or hadn't protruded from the fabric.

I've been getting along with a small pillow and a scrap of moving pad to make up the difference until I had a chance to spend the time to fix it myself. Now I can see what La-Z-Boy really did for me.

When they opened up the seat to put in the new padding, they cut and tore the cabling to the motors. What they didn't get with a knife in the first pass, they just tore by yanking. Real sweet. Next time I want this sort of service, I'll put my chair in the driveway with a "Please Vandalize" sign on it. The same was done inside the back, somehow they missed two of the cables.

The new padding was just as good. A folded over piece of cheesy, low density "egg crate" style foam was shoved into the seat and the back. None of the old crushed-down foam was removed. Needless to say, no accommodation was made for the wiring.

For some reason they opened up the upholstery on the sides of the chair as well. I have no idea what they were up to there. Pushing out the sides to make the whole chair look more puffy? I have no idea.

So if you've got some La-Z-Boy furniture, do yourself a favor. Don't take it back to their factory for work. It's a rip-off. Chances are you can find a small upholstering business nearby that you can hold accountable for the work, so even if they mess up your furniture, you'll have some recourse.

Rolling My Own

I've finished the seat now, and repaired all the wires to the motors. Fortunately, only the wiring was damaged. It took me most of an evening to go through, test each motor, and get it hooked back up to the correct position on the motor controller.

For the padding, I removed the crappy eggshell stuff (it was dirty looking, and even though it was shoved in under all the other padding that was in the seat, it smelled pretty bad, like hydraulic fluid.) I cleaned up the padding that was worth re-using from the original stuff, put in some new stuff where necessary. I added a layer of the fiber material that lets the fabric breathe just under the fabric.

Last night I got the seat back in, it feels much better. Sewing things back up was a bit of a chore, but the results are worth it.

The back is still waiting for me to repair its motors and update the padding, but it'll be a lot easier to work with.

Model Railroading: It's Baa-aack!

2011-03-01T22:07:00.000-08:00

Model Railroading is a hobby that's been at the edges of my life for a long time. And now it's entered from a new direction. But first to recap:

Round 1

When I was a kid I got interested in model railroading early on. As it was, I loved trains, and I lived in a train town. Even at 3, I was drawing my own trains with such detail that my mother had to look at the real thing to see what all those details were that I was drawing.

The idea of owning and running my own miniature railroad was certainly appealing.

But, we moved around a lot and model railroading was not an inexpensive hobby. I managed the next best thing in the way of hobbies: electronics. I built a crystal radio (and used it--a lot), and built circuits on those 50-in-one and 100-in-one kits.

Round 2
As a teen, I got interested again. I had some income and I got a starter set with a locomotive, some rolling stock, track, and a transformer. It was N scale, perfect for an apartment dweller. I built up a setup, some scenery, and had fun with it. But for too short a time. It was enough to get engaged, but not really to get deeply involved.

Various things got in the way. Fortunately, electronics still fit into my life as a hobby.

Round 3

I was grown, married, and had kids. What better time to start a new set-up? I still had some of my N Scale stuff. I bought some wallboard, cleared a desktop, and started work on the layout. I laid what track I had out on the board, intending to build up as I bought new parts. For now, I'd get a train going around with a couple of buildings to amuse the girls and let them see what we were up to. We managed this much, but then...

The garage where I set it up is also where we let a couple of our cats sleep at night during winter (they were outdoor cats.) They decided that the train set was "contested territory", and decided to claim it in the destructive method that male cats have. Fortunately the transformer, locomotive, and stock were all packed away. But most of the track was rendered unusable by the, um, corrosive fluids.

I planned on setting up a new layout with a cover over it. But other projects came along, and time slipped away. For about ten years...

Something New

Last night my younger daughter finished her homework, and we both had some time to kill. I fired up YouTube to watch some model-making videos. She asked to watch model railroad videos. So we watched a couple of things about making layouts. Which I roundly criticized, since I hate styrofoam and that was what was being used in these videos (yeah, I can understand why--I still hate styrofoam.)

Then she let me know she was interested in model railroading. She still remembered that short-lived setup we'd done together before the cats got to it. And she's looking for a crafty outlet. The more she learns, the more interested she gets.

I gave her the run of my small model railroading library (a collection of old N Scale and HO scale books like N Scale Primer and 101 Track Layouts). Today we stopped at Nor-Cal Train Shop after I picked her up from school so that she could see what it'd cost to get her own starter set. She talked with Jimmy there for about an hour and a half.

I guess she's interested.

He sent her home with a couple pieces of track and a couple of pieces of rolling stock to keep her inspired, as well as some magazines she's been reading all night around housework and homework. I've promised to move a file cabinet out of her bedroom that my wife and I left there after using it for a computer room years ago, she's trying to figure out how large a set up she can start with, and planning out ways to earn money to pay for the starter set so she can start operating something.

Her real interest is the modelling, though, it seems. Scenery, buildings, basically building dioramas with something that moves in them.

To tell the truth, I'm pretty surprised. This has all been rather sudden, for me. I wonder how long it's been percolating?

She seems committed. Telling her she couldn't just use my stuff, but had to buy her own hasn't deterred her. It'll be interesting to see where this goes.

Model railroading is a neat hobby. As I've learned, even if you don't end up doing much of it, the skills you learn from even doing a bit of it can take you in a lot of directions. I suppose I could say I got an early lesson in digital electronics from figuring out how to wire a reversing section in a track layout.

On top of that, I'm beginning to wonder what I could fit into a really small layout myself...with microcontrollers, of course.

R.I.P. HFE Electronics, Sac's Electronic Part Source

2011-02-16T15:50:00.000-08:00

I wrote a post about the HFE Electronics Store last year. They took over the former HSC Electronics store here in the Sacramento area. I drove by today, and the store was empty.

HFE Electronics. A Valiant Effort, but Now It's Gone.

It looks like they went out of business two or three months ago, based on their Facebook discussion page. I only got down there four or five times a year, but I usually stocked up on parts, tools, and supplies on each trip.

Unfortunately this leaves me without a local storefront supplier for electronics. Our local Fry's Electronics carries enough in the way of components and such to make up for what Radio Shack dropped from their line a few years ago. But the selection of parts like interconnects, switches, and prototyping components they had at HFE was far greater than I'd expect to find anywhere other than an old-fashioned electronics store.

I do buy a lot of parts online now, I'll admit. I have about two shopping sprees a year for parts from places like The Electronic Goldmine and BG Micro. Not to mention frequent buys of parts from regular suppliers like Jameco, Mouser Electronics, All American Semiconductor.

But there's a difference.

At a local storefront, the parts are in my hands today. Plus, I can see them and handle them. With items like switches this is extremely important. I can also buy parts in small quantities speculatively then come back the next day if they work out and I need more (I've done this several times over the years at HFE/HSC. I remember once buying over $100 more in components on both days than I had planned on buying on each of two consecutive days. As I recall, the main culprit was some displays one the first day, and some uP support chips the second.)

Another thing that's important about local stores is their accessibility to youngsters getting into the electronics hobby. I know that for me when I was young, and now my daughters, fishing through boxes of parts and imagining what could be done with them is very inspirational. A couple of the fellows at the shop I haunted in my teens (Wenger's Electronics in Walnut Creek, CA) mentored me on several of my early projects. Plus there was advice I picked up from other customers. Not to mention that Wengers had a rack of bubble pack parts from Jameco, where I got my first 8080A.

A Long Time Since

I've been shopping at what was HSC and became HFE since I moved to the Sacramento almost exactly 25 years ago. Back then, I lived just a few blocks away. I not only stopped by in the evenings (if I had to run out in the evening for something, hey, HSC was next door to a Circle K store. How convenient is that? Pick up milk and potentiometers on the same trip out!) They had great flea markets on the weekends. You could pick up most of an Altair or IMSAI for a song back back then, enough that a little TLC would get you there (I wish I'd picked up an IMSAI for the front panel.)

There were other electronics stores* in Sac back then, plus I was right at the north end of town so it was easier to get to places like Natomas and Del Paso Heights for those stores. Since I moved to the foothills, HFE has been where I go.

This is where I met Dave Baldwin. I followed him home to get a treasure trove of old computer and parts he was seeking a home for. It's where I picked up about half of my test instruments, in various states of operability, that I use regularly today. It's where I've picked up interesting bits for many projects, and bits that still inhabit my parts drawers awaiting future fun projects.

I'll miss it.
----------------------------------------------------------------------------

Note: If you know something else in the area that I don't seem to know about (I already know about Fry's and Radio Shack, obviously), then drop a comment or an email, please!

*I'm using the term "electronics store" to refer to what I consider to be an electronics store, which is not a place that primarily sells consumer electronics. We used to call those "TV shops" or "Stereo Stores". I'm rather perturbed by such places moving in on the term "electronics store" (though many old-line electronics stores were once TV stores or repair shops.)

Home-Made Miniature: TCG Yavuz

2011-02-14T09:35:00.000-08:00

TCG Yavuz in 1:1800

Among the various games I enjoy are naval miniatures games. When Axis and Allies: War at Sea came out a few years ago, I liked the fact that there was an easy source of new naval miniatures (and a decent set of rules). But the minis were in yet another new scale. Traditional miniatures already came in a bunch of different scales depending on rule set and manufacturer. Though things had pretty well settled down to being in either 1:1200 scale or 1:1250 scale for mid-sized minis.

Then came War at Sea with 1:1800 scale. The minis are nice for the size, and given the fact that they're molded in a fairly soft plastic, they've got pretty good detail. Even if it's a bit blocky.

Homebrew Ships
I thought I'd try my hand at making a mini in the same scale. I built this mini in 2007, shortly after War at Sea first appeared, before any expansion sets were released. It's been sitting in a desk drawer waiting for a paint job since then, I just finished painting it.

When I decided to make my own mini, I wanted to make something that I could be pretty sure wouldn't be coming out in an expansion. It'd be pretty silly to make a ship that would be available for a few bucks from the manufacturer a month after I finished it. Also, the ship had to be interesting enough to model and play with. Not to mention that it should be large enough for me to model by hand, without sculpting and casting.

So, a capital ship. But where would I find a period capital ship that's not likely to appear in the War at Sea expansions?

As it happens I like unusual ships with interesting stories behind them (well, who doesn't?) The TCG Yavuz fits that description exactly. A German Battlecruiser built before WWI, it became the Turkish navy's flagship when it fled the British in the eastern Mediterranean, docked in neutral Turkey, then was sold to Turkey by Imperial Germany as an inducement to Turkey to enter the war on their side.

So an interesting German capital ship escaped the scuttling at Scapa Flow at the end of WWI. It served in the Turkish navy until the 1950's.

When modelling something in a small scale, you have to make a number of choices about what you're going to model and what you're going to skip. You want the ship to represent its prototype, but you'll go mad if you try to capture all its details. In my case, I decided to mainly get guns, turrets, and major masses of superstructure on the model, as well as hull details like the belt and the casemates.

What I ended up with is less than perfect. The fore stack is too short. The hull's entry is too narrow. The mass I use to represent the searchlight tower and other structure around the aft mast is too large. But overall I'm pretty happy with how it turned out.

And to date, it's the only TCG Yavuz I know of that's around for War at Sea.

Coding Forms for Hand-Made Programs

2011-02-07T21:55:00.000-08:00

I've posted some of the coding forms I use on my website.

For me, hand coding and hand assembling software is pleasant and relaxing. It's like crochet or embroidery (I do both of those as well as programming.) Something as simple as a printed form makes it nicer, neater, and faster.

The forms of my own I've posted are generic assembly language forms. I've also posted a TI 960/980 assembly language form as well as some programming forms for the HP-41C, HP-67 and HP-97 that I use with all of my programmable calculators (like my HP-35S.)

MAG-85: 8085 Microprocessor Project Software Progress

2011-02-04T22:00:00.000-08:00

With the hardware work on my 8085 microprocessor trainer project about 99% complete, most of my effort over the past month or so has been developing a simple monitor program (a sort of mini-OS) for it.

The biggest part of that OS deals with the user interface (go figure), specifically the routines for controlling the LCD. The most demanding of the routines have been done for well over a year now, ever since I finished testing the LCD display with the breadboard version of the MAG-85.

The Early MAG-85 with LCD Demo Program

When writing my own software while playing with the LCD (i.e. goofing off rather than writing code for the monitor), I've been writing lots of ad-hoc software to write to the LCD or control it whenever I wanted something more sophisticated than "write this character to the screen" or "send this string to the screen". Character out and string out routines were in my early test software. What I needed were things like automatic wrapping at the end of the displayed line and some terminal control commands.

Coding Rule: Make One to Throw Away

The display controller for the LCD has a larger "display" area than the LCD actually displays. Its buffer holds two lines of 40 characters. That's really nice on my other display which has a 40x2 LCD display on it. But the MAG-85 uses a 16x2 display. This means you can send characters to it, and it'll happily accept them and put them into the buffer in places that the LCD doesn't show. So you don't see over half of what you write. Or you need to keep track of how many characters you've written since the start of the line and wrap to the start of line 2 yourself. And so on.

In my first shot at a set of LCD routines for the system monitor, I wrote a bunch of stand alone cursor position tracking and movement routines. Then I had to invoke them from all over to keep track of stuff. And since the software had to do its own tracking, stuff would get missed, the LCD would get out of sync, and it became standard practice to re-home the cursor and display every so often to keep things from going off track for too long.

Plus the number of routines was getting out of hand, along with the size of the software. I'd intended the software to come in somewhere around a page in length, and I was at about twice that with only about half the software implemented! For comparison sake, a system that uses a hardware approach to display control (e.g. LED or other simple segmented displays with data buffers and select logic) rather than software like the LCD uses fits the whole monitor into about 1K of memory. I was looking at my LCD routines taking up as much room as the whole rest of the monitor.

Frankly, I felt that I was going the wrong way, and it slowed me down in getting the monitor done.

Coding Rule: Make Another to Keep

I decided to strip the code back to my original tight routines. All they do is initialize the LCD, send out a character or a command byte, or a string of characters. First, I dressed up my initialization routine by moving out some recurring code for delays into subroutines. This not only reduced the size of that routine, but made those subroutines available elsewhere.

Then I looked at my character out routine, and decided to put the intelligence about where the cursor was in there. After all, if it gets written this is where it happens. I built in an automatic wrap. It seemed to fit well, and it took a lot of heat off the user code. Suddenly things were looking a lot better.

Once I got to rewriting some of the other added functionality, it turned out smaller and simpler. It went so well, that I'm much farther along in implementing everything I want than I got with the old code. And at present I'm only just over a page in length, without having gone back to look for optimizations (repeated code and so on.) That'll come next, after which I'll be desk=checking my stack handling as I jump around between different routines.

But I'm much happier, and I've got a lot more to show for my time this time. It's nothing revolutionary, but there are times when it's a breakthrough just to step back and see the obvious.

My Students Laugh, HaHa, Laugh, at the HN Naysayers ;)

2011-01-25T14:37:00.000-08:00

I'm gratified by the response my recent article Should I Still Learn Java? has received, especially at sites like Hacker News and DZone.

Among the comments at HN were some folks who felt that Java is a poor choice of language for beginning programmers. There were a number of reasons given, many of those reasons are pretty far removed from the beginner, I feel. Then there were some that trotted out that other old argument, the complexity of the "Hello, world!" program:

class HelloWorld{
    public static void main(String[] arg){
        System.out.println("Hello, world!");
    }
}

It's an ugly-looking mouthful, I'll admit. But a complete obstacle to learning Java? Not even close.

If you're studying Java on your own, there's a lot in there that tends to get glossed over in texts on Java. In writing, it's hard to strike a balance between infodumps and magic code when you're trying to maintain a pace to the narrative of the book. I've broken down the elements of the basic program in several articles at my other blog A Beginning Programmer's Guide to Java, including the articles on the Basic Program Skeleton, Code Blocks, and main().

But how long does it take to cover this material in class? Can it be done without sending the students into the Land of Nod?

The Proof is In the Results

Actually, it's far easier to cover in class than it is in print. I teach the basic elements of Java to both my 6th-8th grade classes and my high school classes. Here's how things went today, in my 6th-8th grade class:

I introduced the class to what we were going to do today (write a simple program in Java, compile it and run it.) I had the students open a terminal window and a text editor then started writing out the HelloWorld program pretty much as it appears above. I explained each word as I wrote, as I do in the articles linked above.

Along the way, I got class interaction to make sure they were with me, that I wasn't just talking to the air. It gave some of them the chance to affirm their ideas about what I was telling them, others that had been a bit lost got it when we reviewed it.

I had them enter each line in their editor when I finished writing each line on the board. I explained the value of proper indentation, capitalization and the parens as part of the naming of different elements in Java (class names, method names, constructor methods, member fields.)

The class was able to anticipate the last curly brace in the program, and the lack of any indentation. It's great when they can already see where you're going.

Then I went over how to save and name the file, having them use 'pwd' in their terminal window to make sure they saved the file in that directory from the text editor. After saving, they used 'ls' to see that the file was there (one student caught an error that way.) pwd and ls were commands they were already familiar with, as well as general use of the command line.

Then I had them use 'javac' at the command line to compile the program. A few students had capitalization errors on the class name, and there were some missing semicolons. After a moment, the files had been corrected, saved, and everyone had a successful compile (we reviewed the "no news is good news" rule for the Unix command line.)

We then used 'java' to run our programs.

Elapsed time: 30 minutes.

Did Anything Stick?

Then we reviewed the program, word by word. I pointed at each word (including each part of System.out.println() ), they told me what it meant. I let each student have a go before affirming what it meant. They nailed them all, except for static. That was the only word that they were fuzzy on. In some cases they had a sense, but couldn't express it clearly. In other cases they just plain weren't sure.

So we reviewed what "static" does in the program.

Then I told them to change what the program prints, and add additional program lines to print things of their own.

They went to their editors, I hovered over. A couple of students needed reminders that the program needed to be recompiled once they'd saved an edited version.

Then they all had programs that had been customized, run with no errors.

Total elapsed class time: 40 minutes.

Then we talked about the differences between the source code and byte code files (see The Code Code), looked at the .java and .class files with 'cat' and 'strings' (a new command to them).

After looking at the .class file with 'strings', we talked about where the extra lines like '/java/io/PrintStream' came from and what they did. They nailed it, but then we've talked a lot about I/O in class.

I did a quick review of all the words in HelloWorld.java one more time, then spent the last few minutes of class covering what we'll be doing in future classes.

Finally, I asked them how complicated they thought today's lesson had been. The consensus was "pretty complicated, but not too complicated." I asked for votes for "really complicated" and got none.

Total elapsed class time: 55 minutes.

Preparation

Part of the reason for getting so much done so quickly comes from the value of face to face interaction between student and instructor. This doesn't happen with books in most circumstances.

Part of the reason for success like this comes from preparation. The students already knew the basic tools of the command line and the text editor. The commands 'javac', 'java', and 'strings' were new in this class.

The students had previously edited HTML by hand. Want to talk complicated? Try this:

<html>
<head>
<title>Hello, World!</title>
</head>
<body>
<h1>Hello, World!</h1>
<p>This is my first web page.</p>
</body>
</html>

We do that in one class in the first semester.
By the end of the class we've had time to either add images or start styling our text. Kinda helps put the whole "boilerplate code" issue of Java into perspective, doesn't it? I seldom hear it claimed that HTML is too complicated for beginners to learn.

We've also done some programming in BASIC this year. The old GWBASIC, in fact. No graphics or sound, but just some simple text and calculation programs (like an insult generator and a die roller) inside the GWBASIC interpreter environment.

I drew on all these things, as well as our other discussions about the internals of the computer system and its OS in the course of this lesson.

Will It Still Be There Next Time?

If I don't follow up with anything else, no, of course it wouldn't stick as anything other than an exposure experience. But there will be follow up.

My 6th-8th grade classes meet once a week. One week is a long time for kids at this age. My high school classes meet twice a week, for 85 minutes per class. I cover a lot more material, faster, with these students.

Based on past experiences teaching this same material, I expect most of the class to remember what the program does, and the meanings of the following words once they see the program again:
public class void (for some reason this one seems to stick) System out println
About half the class will remember the function of the curly braces versus the parens. About half (usually the other half) will remember the capitalization rules.

One or two will really remember 'static', the rest will need a refresher on that.

Which, for students from 11 to 14 years old, with only one hour a week, is pretty darn good. When I originally designed these lessons, I expected to repeat all the material from the first lesson in a slightly different way in a second lesson to get even half the material to stick.

As it is, the second lesson usually consists of about 10 minutes of review from HelloWorld.java, then we go on to introduce the Scanner and start accepting keyboard input into our programs (see Getting Keyboard Input for Java Apps, we end up with a program pretty close to TrollTalk.java.)

Is Java Too Complicated?

What do my students say to the assertion that Java is too complicated for a beginner to learn?

They laugh at it.

People who assert that the boilerplate in a simple Java application is too much have either had a poor exposure to the language themselves (please check out my other blog at A Beginning Programmer's Guide to Java, I wrote the site just for you), or they're advanced programmers making mountains out of speed bumps as stalking-horse arguments against Java.

Java isn't simple, but it's not too complex for a beginner.

p.s.-I love Hacker News myself, and take all my students there to open it up to them.

Games for Christmas

2011-01-04T17:38:00.000-08:00

This year our presents were heavy on games. In part, this is because our friendly local game store, Ship It! Games, has closed its doors. A sad event, but we were able to buy a bunch of games at bargain prices before they were gone.

We're really going to miss that store. Fortunately, we're still in contact with Chris Wright, the owner. He's a great guy and everyone here at our house wishes him well in his future endeavors.

Ticket to Ride

The first game that got opened was Ticket to Ride by Days of Wonder. This game has been around for a while and has won many awards. I've heard a lot of good things about it.

We have played it several times now, and we agree. It's a great game.

What's special about the game is that it doesn't take a whole lot of thinking to play. There is a strategic element, but if you're brain-fried after a long day at work, this is a game you can still pull out and enjoy, even with opponents who are at the top of their game. It's fun, easy to concentrate on short term objectives if that's all you're up for, and the set is designed very nicely too. Five stars!

Growing Hunger

Next comes the expansion to Last Night on Earth: The Zombie Game by Flying Frog Games. Growing Hunger adds several new scenarios and heros, as well as new cards, items, and so on. It makes LNOE a much stronger game overall, though the new cards dilute the old cards when added to the decks. The place where this is a problem is mainly with the Zombie Deck. The "Shamble" card, in particular, comes up less often than it should. We may convert a few of the present cards into Shamble cards, or add the Shamble power as a secondary use for one of the other cards to try to rebalance things.

Munchkin Quest

We haven't played this one, yet, but we're really looking forward to it. We really enjoy the Munchkin card game (that's our other "I'm fried and don't want a game that makes me think" game.) Unfortunately, the rules are very poorly written compared to the card game. They're very confusing, poorly organized, and long-winded. This is the opposite of the writing in the card game's rules.

Fortunately, it looks like a lot of the card game is in the board game. But I can tell our first game or two is going to be exploring the rules and trying to get them right. Steve Jackson, get an editor or another writer to redo those rules in a future printing! I was able to play Stellar Conquest properly first try, lo, these many years ago. I can't make heads or tails of a bunch of the rulesheets for Munchkin Quest!

Warcraft
This is another one we haven't played yet but are looking forward to. It looks like a game based on Warcraft II, with some World of Warcraft and Warcraft III elements in it. The pieces are not as nice as we were hoping for, and to be honest we've been pretty spoiled by the fantastic sets that Days of Wonder produces (we've got Small World and, of course, Ticket to Ride from Days of Wonder.) The Warcraft pieces are wood, but they're kinda crude chiaroscuro shapes for different general unit types. But we've enjoyed other games from Fantasy Flight Games (notably Talisman, which they rescued from fading away right after we bought our fourth edition copy, and its expansions.)

Ah, well, the real telling will be in the game itself.

Demented Dungeons

Munchkin is one of our favorite "play me anytime" games. We have the original core set plus the first expansion, Unnatural Axe. And now we have "Demented Dungeons"! We're really looking forward to adding the Dungeon rules to our game. One of the great things about this expansion is that it won't make our door and treasure decks taller, putting off the day when we'll need to build or buy a deck holder for our Munchkin cards.

Retrocomputing for the Holidays

2010-12-04T18:14:00.000-08:00

What could be better than an old computer under the Christmas tree? It's a fun, inexpensive gift. There's always something old under out Christmas tree. Among the larger items have been the Commodore 64 that I gave my daughters as their first computer ten years ago. It included a monitor and floppy drive, of course, and copies of the user's manual and programmer's guide.

They'd both already started programming in BASIC on my Apple IIe during the prior year. So they were ready for the C-64! I got myself a Softcard for my Apple IIe that same year.

Two years later, I added a Plus/4, since they were frustrated with the lack of direct graphics commands on the C-64. Peek and poke wasn't good enough. ;) That same year some friends gave me their Laser 128 (Apple IIc clone.)

Christmas Cheer with PA-RISC

Another two years pass, and they both got an HP9000/700 series Unix workstation. They spent Christmas break learning Bourne shell and playing with Neko under X-Windows. Yeah, these weren't 8-bitters, but they were fun old systems that ran plenty of network apps. I had a MUD on my Unix workstation, and they learned how to telnet in and play pretty quickly. Their typing improved dramatically.

I picked up an Amiga 500 and that became the family's Christmas present the next year. We hooked it up to our 36" TV and played music, games, and a bunch of demos.

The year after that, a friend gave me a Bigboard I system. CP/M, 64K, and two big 8" floppy drives. Wordstar and BASIC-80 heaven. Everyone gathered around to roast chestnuts over the power supply and listen to the disk drives churn. ;)

Sure, it's got iTunes. Does it do X-Windows?
That same year, my daughters got upgraded to Macs, G3 B&Ws. They were excited about getting a computer that would run iTunes, but first they made sure that all their Unix stuff would run as well. Once they were sure they weren't giving up the Unix command line and could port their applications, THEN they were OK with the upgrade.

Three years ago, I did some repairs to a Kaypro 4 to get it working again. Unfortunately I haven't figured out how to read and write standard diskettes with it yet. It's a souped-up unit, with an aftermarket ROM, hard disk, and floppy drives that include both double and high density units. It got set on the back burner in favor of some other projects, once they're finished I'll get back to determining if I've got all the right software to go with the ROM that's in the system.

Visiting Old Friends

Two years ago, I actually avoided adding any new hardware for the year. Instead, I spent time during the holidays pulling out several of the systems I have that have been a bit neglected and giving them some TLC then playing with them. The Apple IIe, my own C-64, another Plus/4, and the Big Board.

Last year was the year of hardware projects. I had a new 8085 computer on a breadboard (see the story at http://saundby.com/), and was preparing to move it to soldered circuit cards. I was also migrating my Ampro Little Board (a Z-80 system) from loose components on the table top to living in a box like a proper computer.

Bringing Up the Ampro Little Board

Catching Up for Christmas

This year I'm working to finish the non-breadboarded version of my 8085 and building up a Membership Card (1802-based computer, similar to a COSMAC Elf from 1976 but a lot smaller) in a decorative little Victorian-style case. I'll be posting that on my web page at saundby.com soon, I expect.

I'm keeping my eyes peeled for a Commodore 128 at the thrift stores, too. That'd really round out this Christmas year.

What's on Your List?
What retrocomputer experiences have you had for Christmases past, and what are you hoping for under the tree this year that's hopelessly "out of date"? :)

Repairing the "Unrepairable" Microscope

2010-10-20T12:08:00.000-07:00

The school I teach at has a small number of microscopes used by our science classes. I also use them once a year for a lesson where I bring in a bunch of microcircuits made visible to let my students see what's on a chip directly. I also bring in a wafer and some dice (the microcircuit variety, not the Yahtzee variety) for the kids to see and handle.

The exhibits themselves range from a 1959 transistor with the top of the can cut off to reveal the chip and a 1965 dual op-amp similarly prepared to a 1st generation microprocessor to late 80's memory circuits. All together I have about six to eight things I can put under the microscopes that would be interesting to look at.

Since I've been with the school, one of the microscopes has had a label on it reading "Broken, Save for Parts" on it. Since there are only six microscopes, including this one, it means I have to spend time in class changing over each scope from one object to another. Fortunately I've gotten good at talking while focusing a scope and shifting the light and indicator around to the best position. But it would be awfully nice to have at least one more scope. Recently another of the scopes got damaged, reducing us to only four scopes. This is really too few, especially for our science classes.

I Can Fix That

Our science teacher found out I work on optics (I build telescopes as a hobby, in addition to my work with sensor systems professionally.) She asked if I'd be willing to take a look at our newly broken scope. I agreed, and suggested that I might take a look at the "parts only" scope as well, since neither of us knew what was wrong with it.

The office staff let us know that the other scope had been declared "unrepairable" by a scientific instrument repair service that had looked at it several years ago.

When I took a look at the "unrepairable" scope, the optics appeared to be in perfectly good condition. The adjustments and controls were likewise all in good condition. All I found was that the light built into the base did not turn on. I had a light handy, for my own scopes I prefer a light that isn't built into the base, that way I can just grab another light if one of the bulbs burns out when I'm in the middle of a job. More than half the time I'm looking at something opaque anyway, and when I do look at translucent samples I use a mirror as often as I use a lamp for a backlight.

I opened the base to the "unrepairable" scope, wondering what would prevent the light from being fixed. Perhaps a small fire from a prior fixture?

Since When Is A Bulb Replacement "Unrepairable"?

When I got inside there was nothing worse than an empty light socket. The previous light had burned out, been removed, and not been replaced. I could see why, in part. It was an odd sort of bulb. The base style is the same as that for an automotive type "1004" bulb. It's a bayonet mount with two contacts at the tip of the base rather than the usual one. The designation is BA15D. It's an unusual type of bulb, especially for 120V. They run from about $5 to $35 depending on how specialized your supplier is. But they're not unavailable, by any means.

Still, they're hard to come by for people used to picking up light bulbs at hardware and grocery stores, so I decided to replace the base with a more common screw base. A standard medium size screw base, as used on most incandescent lamps around the home, would be too large to fit in the microscope's base. A small "candelabra" base would fit handily, but I wanted to make sure it'd be easy to get lamps in the right range of brightness. Candelabra base bulbs of up to about 15W are easy to come by in a size that would fit. But above that they tend to be the larger "flame" shaped bulbs in the 25 to 40W range, which wouldn't fit properly.

So it came down to an "intermediate" size screw base. Bulbs for these are common at hardware stores and such, as "high intensity" lamp bulbs (in 40W), and as lamps for vacuum cleaners, appliances, and such. 20W to 40W are common.

You Can Get the Bulb, But Not Its Base

Now the problem was finding such a base. I checked several hardware stores and lighting stores, with no luck. They all sold bulbs to fit an intermediate base, but no actual lamp bases in that size. I checked Radio Shack, just on the off chance, and my prejudices about their current parts stocking were confirmed. I even considered using the halogen lamps with the loop and straight leads on them. While the lamps are readily available, once again the bases are not.

I went to several stores and looked at cheap lamps, looking for one I could cannibalize without paying too much for the privilege. No luck, the LED lamp rules there, and none were suitable for a microscope. Neither the light pattern nor the size would work.

Finally I tried yet another hardware store while I was in another nearby town. I was ready to give up on intermediate size and go with candelabra, and hope to find a 20 or 25W bulb to fit. They had a single bulb wired fixture with a candelabra screw base. It looked perfect. The fellow minding the shop floor mentioned a lighting store nearby that I hadn't been to, as well. So I bought the candelabra fixture, a 15W bulb that would fit it, and headed over to the other store.

There they had lamp components in parts drawers, a very promising sign! I found several different types of base, but all in candelabra or medium size. One of the workers there helped me look, but we didn't turn up an intermediate base. We did turn up an adapter to go from a candelabra base to an intermediate base, though. I got that and a 25W bulb to fit, then went home with the lot.

Once home, I test fit the new fixture in the base with duct tape. I pulled out a selection of slides, and selected one with a nice thick feather sample on it to test the light level. I started with the 15W bulb and a thick section of the feather. The 15W bulb illuminated it, but not as well as I would like for students. Student's eyes aren't trained to pick out details yet. They need things well illuminated to help them see what they're supposed to see.

Putting It Together

I put in the adapter and the 25W bulb. That worked perfectly. Bright enough, without being too bright, even with a bacterial sample on a slide. In fact, the bulb aligned with the reflector in the base better with the intermediate base adapter. So I removed the old fixture from its bracket. Prepped the bracket and plastic welded the new base's fixture into place. I cut out the old fixture's wires, desoldered one end from the light switch, soldered and spliced the new fixture in. When it was all done, it looked like it was supposed to be that way. I tested everything to check for operation and safety afterward.

Then I added some labels to describe how to change the bulb to the outside of the case, and what bulb to use.

Now the "unrepairable" microscope not only works great, but can be maintained by an ordinary person without calling the "scientific instrument repair" service.

Back on World of Warcraft

2010-10-04T21:37:00.000-07:00

While the rest of the world is playing Starcraft II and free MMORPGs, I've just returned to World of Warcraft. Not only my own account, but three others for my family. After a two year hiatus, why am I back?

No TV

For some time now I've not had a good activity for when I'm too fried for anything serious. We don't get broadcast TV here, and satellite isn't worth the price. 300+ channels and nothing really worth watching. Normal broadcast channels cost extra. Thanks to my Congress passing bills to "protect" me, I can't get national network feeds over satellite any more, as I did about 10 years ago. Then I could watch shows I wanted to watch on my schedule, rather than being beholden to the "local" stations (the satellite companies consider Sacramento local to me, even though I'm about midway between there and Reno.)

Radio Static

Listening to radio is something I usually do while working on something else, so it's not an activity that's engaging enough when I just want mindless entertainment.

DVD and VHS Overfamiliarity

If I hadn't already watched my favorite "watch them anytime" disks and tapes to death, I suppose I could do that. There's a lot of material in Connections I/II/III, Day the Universe Changed, The Learning Company's Astronomy course, and several others. But when I get to where I can lip sync with them, it's time to find something else to do.

WoW

WoW is more fun with a group. Pick up groups aren't fun, for me. So I looked at WoW's charges with an eye toward "how does this compare to satellite TV?" I came to the conclusion that it's reasonable to spring for four accounts for the family to get my own built-in group.

My Account

I got an account about the time WoW was generally released to the public. I had some "real life" friends to play with, as well as friends who'd moved over from Everquest for the Mac. My kids played on my account when I didn't. They'd hot-seat, or I'd give play time as a reward or inducement to do homework or chores or whatever.

The Kid's Accounts

Then, as the kids got older (teens), they wanted their own accounts. I gave the green light, provided they saved enough money for their own retail box and six months of service. They both did so, and they could keep playing so long as they paid for it. After some time, they both decided they'd rather spend the money on other things. We suspended their accounts, and they went back to playing on my account.

Leaving Azeroth

Meanwhile, my various friends either left WoW or I lost track of them in real life as well as in-game. I ended up on a new server in a small casual guild. But I was mostly playing solo, I was losing interest, and the guild was dissolving. The community on that server just never really gelled. I considered moving to another server, but various other things were keeping me from playing much, so I deactivated the account about 18 months ago.

Return to Azeroth

Now I'm back. I reactivated my account, and had my daughters reactivate theirs. This time it's on my dime, so long as they keep up with homework and housework. Plus I got a fourth account. It's for my wife, who never played before.

Non-Gamer

My wife was once a non-gamer. But over the last few years she's enjoyed joining games--due in large part to our daughters. She's played tabletop RPGs like Traveller and Pathfinder and enjoyed them. We also play a lot of board games like Cosmic Encounter, Quirks, and Settlers of Cataan. It's a big change. I couldn't get her to play games before the kids came along.

Now we've got her on WoW with us. We played for about 3 hours this last weekend and had a good time. It was challenging for my wife, she's not familiar with computer RPGs, but everyone was patient. We had her roll up a hunter since they're pretty easy to play and a forgiving class. She managed to learn the basic controls, get around most of the newbie zone without getting too terribly lost, and made level 8 in her first session. She professes to have had a really good time.

Time Filler

Meanwhile, I've got a fried-brain spare time activity. This afternoon my youngest got through her homework quickly and did several chores--unasked!--so that she could play and get a character to one of the special little seasonal activities in WoW before it goes away for another year. I'll still have time for my hobbies--WoW doesn't replace actual things like electronics and telescope making for me. But when I'm not up for those, I won't be casting around aimlessly as much.

We won't be able to coordinate family schedules well enough to play more than perhaps once a week all together, but that will be enough. We have other family activities we do as well, like reading, that take some of that time. Right now we're working our way through Watership Down. Only I have read it before. We read for about 45 minutes this weekend before we jumped on to WoW. If we manage as much as a couple of hours a week together on WoW, that' good enough for me to justify the accounts.

An Update to the First Heavier Than Air Flying Machine

2010-09-30T12:42:00.000-07:00

In July 1869, when Wilbur Wright was two years old, and Orville was as yet unborn, a heavier than air flying machine successfully flew two half-mile circles in a tethered flight test. The craft was known as the Avitor.

Lost in Time

The Avitor has been largely forgotten. It was what we'd call a hybrid vehicle today, very unlike the craft later flown by the Wright Brothers. The Avitor flew well and successfully, but an accident with a prototype resulted in its development being halted prematurely. If development had continued, it's very likely that modern aircraft would be very different from what they are today.

Many of the design concepts of the Avitor are being rediscovered and applied to new aircraft development. Among these are aerodynamic lift from the aircraft body (Blended Wing-Body aircraft, today) and hybrid lift (lift from a combination of buoyancy, power, and aerodynamics.)

The Past is the Future

The closest thing to a modern day Avitor is currently in development by Northrop Grumman. It's a vehicle they call the Long Endurance Multi-Intelligence Vehicle, or LERV. The name describes its use, something that can hang in the sky for long periods of time keeping an eye on things. The present program's goal is to develop a surveillance platform for use in Afghanistan. It is supposed to go there for operation testing within a year. First flight is to come this summer.

After a Brief 150 year Hiatus, the Return of Avitor?

There are other potential applications for this craft that Northrop intends to work toward. Perhaps by the Sesquicentennial of the Avitor's demonstration flight, we'll have our own 21st century Avitors roaming the skies.

Related Links:

Flying Machines--Frederick Marriot

Hiller Aviation Museum--The Avitor

Mark Twain: Frederick Marriot and the Avitor

Northrop Grumman: Long Endurance Multi-Intelligence Vehicle

8085 Disaster! (well, a minor setback, but I'm not happy about it.)

2010-09-18T02:48:00.000-07:00

I'm in the final stages of assembling the permanent hand-wired version of my 8085 project, and I've run into a problem.

3 Switches Become 1 Big Problem

There are three critical switch inputs to the 8085 on the front panel. They are the TRAP, RST5.5 and RST7.5 signals to the 8085. Essentially, each tells the 8085, "Stop what you're doing and do this instead."

It Worked Fine on the Test Bench!

When I built this project on solderless breadboard I didn't have any serious space limitations, so I did full "debouncing" on each switch, to prevent electrical noise caused by the switch from sending a whole bunch of "stop what you're doing!" messages all in a row when the user just presses the switch once.

On the soldered-up permanent version, I decided to save a little bit of space on the circuit board by trying to debounce on the cheap. A normal debounce circuit uses two inverters to clean up the electrical noise. I had a chip on the board that had six inverters in it, two of which were in use. That left me four inverters, for three signals. I needed six to do the job right.

Too Clever by Half

But, I had a "clever" idea. I thought I'd see if I could get by with a circuit that only uses one gate per signal. Not a full debounce, but a circuit called a "Schmitt Trigger." I built it up and tested it on the solderless breadboard.

It worked just great!

Then I built it up on the soldered board. It worked great there, too.

Then I went and bought some prettier switches to use on my new system's box. It worked pretty well. It seemed OK...

Then I did a test fit on the box with all the parts. I pressed my pretty new switches.

Disaster!

When I was pressing the new switches on a handheld box, rather than against a tabletop, I got a whole bunch of signals sent to the 8085 for each time I pressed the switch. The results were pretty ugly.

A Quick Fix is No Fix

I tried out some quick-fixes, as well as making sure all my connections were good. I'd hate to redesign and modify the circuit only to find out the problem was a loose connector all along. The connectors were tight, and the quick fixes helped a bit, but didn't fix the problem. The original (ugly) switches I used worked fine, but I tried a selection of switches in the circuit and most of them had the same problem when hand-held even when they didn't have any problems on the test bench. (I really did test the snot out of this when I first went with the shortcut. But I didn't get all the conditions right for a good enough test. Now I'm paying the price.)

I considered changing out the switches. But this would be a bit of a cop-out. I want to make this something someone else can build and enjoy without having to go through the tweaking and testing and all that I'm doing as I build it. I want others to be able to build it and just have it work, so long as all the bits are in the right places. I can't guarantee that everyone who decides to build it is going to get "clean" switches. So I have to go back and change the design to use real debounce. Then test that, under adverse conditions, like with a rusty knife switch.

One of the quick fixes I tried would probably have been good enough to work under most conditions with a software change that would have delayed any action on the switch input for a fraction of a second. I could have gone with that, and felt sorta pretty good about it. Except that there's a fairly likely condition that that wouldn't cover.

The Deadly Condition

If the user presses the switch, and holds it down for a bit before releasing it, there'll be a second switch event on the release. If someone has a habit of sort of "leaning on" the switches then this will occur to them fairly frequently, and probably ruin their experience using the computer.

I did say these switches are important--in the OS I use them for a warm reset, and vectoring to the user's program. The third one is left for the user in their own programs. But if those functions aren't reliable, it sorta hoses the whole affair. So it's time for me to do the right thing.

Test, Test, Retest, Pray and You Shall Receive

Tomorrow I expect to be protoboarding the correct circuit that I probably should have done in the first place. I'll test it, and if I'm not 100% convinced, I'll use a different sort of circuit, called a "one-shot" or monostable, and make darn well sure with belt and suspenders and a rope tied to a thick tree limb. I may try to avoid adding another IC to the board by using transistors for the last two inverters, or I may try to keep down the varieties of components I use by just dropping in another 4049 in addition to the one there now. On my other part choices I've opted to keep the number of different parts low by reusing the same chips over and over wherever possible.

I'm expecting to put in another 4049, even though it ties up more board space than I like. I might get creative about where I put it, but then again I may not.

Finally, Fitting It In

It's not like I don't have open board space. But I had plans for that space in the future. A memory bank select, another memory IC, and an RS-232 chip. I think the space saved for the RS-232 chip is going to get used. Besides, I may be able to fit in a little Dallas/Maxim chip in one of the odd corners later, or just "float" it on a daughterboard connected to the RS-232 connector.

After all, the core computer has to be working before I start worrying about expansions.

Cartooning Class: Drawn While You Watch

2010-09-15T11:01:00.000-07:00

Today I'm preparing for the first substantive lesson this year in the cartooning class I teach. The first class, which was last week, is a get acquainted class, and I introduce the idea of drawing faces on circles as an activity. This week we start working on technique. I start with drawing eyes.

Each year, I'm tempted to bring in pre-printed sheets with examples of different artists' eyes on them. But each year, I end up discarding the idea, for the same reason. It'd be convenient to have specific examples from cartoons the kids recognize (and some they don't, yet) right in front of them as they work. Plus, even with my notes there's always something I miss covering (though I usually pick it up in review the following lesson.)

But I don't.

Watch the Cartoonist Draw, and Fumble

I think it's important, especially early in the class, to give the students confidence. Part of that is letting them watch me actually draw my examples on the board for the class. Aside from the fact that they get to see how I perform the strokes of the drawing, they also get to see my mistakes. They also get to see me hesitate as I prepare myself to shift from one style to another, and think through the details that define the new style (I do it verbally, so they can hear me think it through.)

I try to open up the process of drawing to them, so that they can be assured that it's not magic.

Some of them miss that point on the first pass. But I can point to the drawings on the board and ask questions like "did I get that one right the first time?" to make the point that I'm not perfect, even though I've been drawing these things since I was their age. I also tell them stories of how I learned these things the first time, and how pathetic my first attempts were. I often re-create these on the board or do them extra bad for a bit of humor.

The point, of course, is that the process itself isn't magic. But the results are. And the magic happens almost no matter what our skill level. We can scribble down a few lines on paper that have an emotional impact. At best, that impact hits the artist when they sit back and look at the drawing. But even when there's no impact there, it can hit others. So we pass our drawings around. There's nothing that does more for a worried student than to have a fellow student they barely know look at their drawing and say

"Whoa! That is so cool!"

8085 Computer Power Management

2010-09-14T17:54:00.000-07:00

I'm in the final stages of hardware work on my 8085 computer project. Today I spent some time working on reducing how much power it uses.

The MAG-85 still looks like a rats nest here. I pulled out a bunch of parts for today's testing. It'll go back together again even better.

With all peripherals turned on at full power, some of them at a higher level than would be normal or reasonable, the whole thing pulled 720mA at 5V. At full reasonable power levels, everything on, it came down to about 250mA. I put in current limiting to cap it at that level.

Then I went hunting for further power savings. The plan is to run this thing off of batteries in the not too distant future (I normally run it off an AC adapter now.) By seeing how little power I could feed to the LEDs in the system while still having them visible in bright light, I was able to cut overall power use down to about 160mA with everything on. It draws about 125mA with the LCD display on, the system running full bore, but no extra outputs pulling current. I can live with that.

What surprised me the most was that changing the CPU from an 8085AH microprocessor to an 80C85 (CMOS, low power version) didn't make any significant difference to the amount of power the system required. The LEDs accounted for almost all of the decrease from 720mA to 125mA.

The enclosure during inspection by Quality Control. The first attempt is on the left, the final version on the right.

I'm very close to closing this box up and calling it done. At least until I open it up for further upgrades. Upgrades like full 64K memory decode, an additional 8K of memory on board, and an RS-232 serial port. Later.

Killing Time with Web Comics

2010-09-09T13:59:00.000-07:00

School started this week, I've been busy with the preparations I've made for my classes as well as teaching them, on top of my regular work. I've been a bit low-key otherwise.

While I should be putting the finishing touches on my 8085 computer this afternoon, I've been reading funnies on the web instead.

The one I've been enjoying over the past few days I'm enjoying a lot. It's called Sheldon, and you'll be doing yourself a favor if you click on that link there. There are several years worth of archive up for the comic, so you can read it all from Strip One. I recommend doing it that way--it'll explain a lot that appears to make no sense otherwise.

I first learned of Sheldon through the book How to Make Webcomics. Sheldon's creator, Dave Kellett, is one of the book's authors. I got the book because I've been reading PVP for some years. and I got interested in the book. Among the things I cover in my computer classes is using the skills I teach in business, and I've incorporated some of the material in the book into my lessons.

Sheldon is cute, fun, clean (one mild swear word in almost ten years' comics I've seen so far, and some pretty abstract innuendo is the worst I've seen), and a great way to avoid doing the things I don't feel like I've got the energy for right now. Besides, the weather's turned cold and that means I can't paint the enclosure on my 8085 computer today. Maybe tomorrow, but for now, back to Sheldon. What's that duck up to now?

Siig Multi-Touch Mini Keyboard Wrap-Up

2010-09-04T22:25:00.000-07:00

A while ago I wrote about getting a Siig Multi-Touch Mini Keyboard. I wanted to get something of the sort because I wanted an integrated keyboard and mouse for use in the front room. I didn't want a separate mouse.

Well, after using it for the first few hours, I was pretty pleased. But as time went on I got less and less pleased. The touchpad was way too sensitive. It was registering clicks even when I wasn't touching it. When my palms were on the wrist rest, it would register clicks. I was getting all sorts of problems. Selections were just part of it, it'd be selected on something when I didn't even know it, so when I'd put my finger down to move the mouse pointer, I'd get an unintended drag. I'd see it--you can guess the natural reaction--and end up with an unintended drag and drop.

There's no way to make adjustments to the behavior of the touchpad. Adjustments in the OS don't affect it, nor do mouse adjustment. Siig's support barely acknowledges that the product exists, and there's no help there either.

Well, I tried just catching when it was happening, and tried avoiding making it happen. Neither worked well enough. My typing speed dropped through the floor, the errors continued, and there wasn't much I could do to keep it from happening. I just had to be prepared for it and try to minimize the damage. Not the best way to go.

Finally, I set aside the keyboard and put in another that annoys me with sticky keys. It was better. Two hours of typing later I was feeling better--with sticky keys on the keyboard. That pretty well sealed it.

I took the Siig keyboard back.

I've since replaced it with another keyboard. See my review of the Microsoft Wireless Desktop 3000.

Installing Pygame on Mac OS X Leopard

2010-09-02T12:58:00.000-07:00

In my ongoing campaign to broaden my programming abilities I decided to install
Pygame and play around with it. I want to try it out as something to present to my students this year. I've decided to add a small programming segment to the first semester of my high school computer class this year where we do a quick survey of several languages by doing tutorials in them before we go into Java programming in spring semester.

Pygame is an add-on package for python that makes it easy to develop games using Python. Python has no built-in support for native graphics, sound, etc.--Pygame adds that to Python.

When I went to install Pygame on my Mac, I ran into a couple of hitches. I managed to work around them without too much problem, but I thought what I did to get things going was worth sharing.

First, Pygame requires the python.org version of Python. Even though my Mac already came with Python installed (hurray for Apple for that), the version isn't one that Pygame is happy with. So I went out to python.org, clicked on downloads, and pulled the first thing I saw for my OS version. This turned out to be Python 2.7 for Mac OS X 10.5 or later. Yeah, I could have gone with 3.1, but to be honest I didn't look that far down the page at first.

Once I had it downloaded, I started the download of Pygame. I installed Python 2.7 from the Mac installer while that was going.

Once the Python install finished, I did python -V at the command line in Terminal. My answer:

#python -V
Python 2.5.1

Hmmm. That's the Mac preinstalled version, not the new one. OK, fine:

#whereis python
/usr/bin/python

#ls -l /usr/bin/python
lrwxr-xr-x 1 root wheel 72 Feb 21 2008 /usr/bin/python -> ../../System/Library/Frameworks/Python.framework/Versions/2.5/bin/python

Aha! I needed to set up the appropriate links to make the new Python the current one.

#cd /System/Library/Framework/Python.framework/Versions/
#ls
2.3 2.5 Current
#ls -l Current
lrwxr-xr-x 1 root wheel 3 Feb 21 2008 Current -> 2.5
#ls /Library/Frameworks/Python.framework/Versions/
2.7
#ln -s /Library/Frameworks/Python.framework/Versions/2.7 ./2.7
#ls
2.3 2.5 2.7 Current
#rm Current
#ln -s 2.7 Current
#ls -l Current
lrwxr-xr-x 1 root wheel 3 Sep 2 12:45 Current -> 2.7
#python -V
Python 2.7

Hurray! Next I went to install Pygame. I unzip the zip, then run the installer.

No Install

Pygame then complained that it wanted Python 2.6! Python 2.7 wasn't good enough for it. I took a look at the dependency settings by right clicking on the Pygame installer in Finder, selecting "Show Package Contents", then opening "Contents" and double-clicking on info.plist there to open it in the Property List Editor. I expanded the Root item (the only top level item), then expanding "IFRequirementDicts" and expanding item "0". There I saw the Python version requirements properties. I considered changing it to require Python 2.7 by editing the SpecArgument field to 2.7 instead of 2.6.

But, it's not like my hard disk is mine to control, so I wimped out and installed Python 2.6 by going back to the Python All Releases download page, finding the 2.6 version, downloading and installing it.

Once it was in place, I went back to Terminal:

#cd /System/Library/Framework/Python.framework/Versions/
#ls
2.3 2.5 2.7 Current
#ln -s /Library/Frameworks/Python.framework/Versions/2.6 ./2.6
#ls
2.3 2.5 2.6 2.7 Current

Now Pygame will install just fine.

Old Computer Orphanage

2010-09-01T09:00:00.000-07:00

Computers on my Doorstep
I got up this morning to find a G3 iMac sitting on the floor of my living room. My wife told me a friend of ours had come by earlier to drop it on our doorstep.

What a fun little surprise for the day!

G3 iMac

It's a 450MHz G3--the top of the line--with Mac OS X Jaguar loaded (10.2, one of the best versions of that OS), and it has Classic, which lets it run the OS9 stuff within X. 128MB of memory (remember when that was plenty? What do you do now that you didn't do then? We had web browsers and MP3 players back then, you know.) All in all a very sweet little all-in-one system.

Aside from some cosmetic dings and a missing keycap (up arrow), it's in great shape.

Unfortunately, it's a little too old for me to donate to my school--we'd need at least an Intel processor there, we need to teach on Windows as well as MacOS. But I have plans for building a G3/G4 based game network here at home so that the family and guests can enjoy some of the old games like WarCraft II that we miss so much. I just need to reclaim some space in the garage from my overflowing heap of Apple II stuff. ;)

Microsoft Wireless Desktop 3000 Keyboard/Mouse Review

2010-08-31T11:07:00.000-07:00

My new Microsoft keyboard is great. I needed a keyboard to use in my lap in the front room with a non-Bluetooth computer. I tried out the Siig Wireless Multi-touch first, because it had the mouse and keyboard functionality all in one unit. No mice falling off the arms of chairs that way. And I've come to prefer the convenience of touchpads over mice over the past couple of years.

Wireless Connection

The Wireless Desktop 3000 uses an RF dongle to connect to the computer via USB. Since the computer I'm connecting this to doesn't have Bluetooth (an Eee PC 1000HD), this is about the best I could do. Unfortunately, the dongle isn't one of the sort that's practically flush with the side of the computer. It sticks out like a thumb drive. Fortunately, I'll only be using this set up when I'm not mobile, so it's not that big a deal.

Wireless Keyboard Version 2.0

The keyboard's back states that it's a Microsoft Wireless Keyboard 3000 v2.0. I don't know what the differences are from version 1.0. This one works well.

Excellent Keys

The keyboard itself is nice in that the keys all move freely from whatever angle you type on them. On a lot of similar keyboards I tried some keys, usually the space bar, would stick a bit when pressed from a low angle before depressing. The keys are all properly sized.

A biggie is the placement of the keys, such as CTRL and ALT. They're in the right place, at least they are if you've gotten used to having CTRL at bottom left and bottom right. Many keyboards place a FN key where a control or ALT key ought to go. This gets pretty darn frustrating, especially if you move between as many different keyboards in a day as I do. The Esc key looks odder than it feels. I haven't had any problems using it without thinking about it, and its placement makes the grave/tilde key a lot easier to use. That's appreciated at the Unix command line.

There are a lot of special function keys. They don't mean too much to me one way or another, except for the volume control keys that my Mac has trained me to get used to. The Fn keys above the keyboard are all primarily special keys for various things like opening a folder or whatever. Fortunately, there's a key to lock these to Fn keys rather than special keys for those of us who are more interested in quick access to F1, F2, and so on than to "send email" or "check spelling".

Keyboard Construction

The overall build of the keyboard is light, but very sturdy. It has a little bit of a "Rubbermaid" feel about it, but in fact it's quite stiff and sturdy. The keycaps are well shaped, and have a good texture to them. The lay of the keys on the board is also very good, each row feels a bit elevated from the lower rows, without being a stretch for fingers.
The keyboard comes with its own software, which the manual admonishes should be installed "for best performance." I haven't installed it. The system I use this keyboard with is mainly Ubuntu, and I boot WinXP on it about once a week. The keyboard has done everything I would like it to without any software installs. It acts just like any other USB keyboard.

Wireless Mouse

The model of mouse that was included in the Wireless Desktop 3000 package is a Microsoft Wireless Mouse 5000.

The mouse uses what they call "Bluepoint" technology for tracking, and I've got to say it tracks head and shoulders better than any other optical mouse I've used. The shape is very similar to older MS mice I have, quite tall and bulky. This isn't entirely a bad thing, it's easy to tell what you're up to, and to align the mouse in the hand. But it is chunky.

It's also a bit heavy. It feels like there's a rock in the bottom. But it moves well enough.

The scroll wheel doesn't have any detents, like my older Microsft mouse. This is taking some getting used to. I still feel like I have plenty of control when scrolling, but when there's no immediate response from what I'm scrolling in, the smooth scroll makes me wonder more whether the scrolling is registering. It's a sort of back-of-the-brain thing that acclimatization, more than anything.

Why a ~~Duck~~ Mouse?

For this use I didn't really want a mouse, I wanted something on the keyboard itself, like a trackpad or joymouse. However, I have to say that I'm pretty happy, the excellent tracking of the mouse makes up for having to use a mouse at all. That and the fact that the keyboard is excellent, and feels good when I use it.

Final Ranking
I've been using the keyboard for about a week now, and I've written about 75,000 words of text on it, possibly more. It hasn't vexed me at all, which is saying a lot. I'm considering getting one for my iMac desktop as well.

I'm gonna give the MS Wireless Desktop 3000 a rating of "excellent."

Aaaah. It's a joy to type on a good keyboard.

A First Look at Windows 7 and Snow Leopard (Finally)

2010-08-29T21:25:00.000-07:00

OK, so I tore myself away from CP/M and my Atari 2600 long enough to get my first exposure to Windows 7 and Snow Leopard today. We got my older daughter a new Eee PC laptop to replace one she drop-kicked (accidentally, by all reports), the replacement runs Windows 7. Last week I decided I to do upgrades of some of the Macs around the house to Snow Leopard. So I picked up a family pack of that, and did an install on one of my systems while Windows 7 was "initializing" on the new computer.

Windows 7

Let me be upfront about it. While I'm not a Windows "hater", I don't have any great love for it as an operating system. I don't think it's got any particular technical excellence about it, it's got a legacy of problems that tend to persist from version to version, but by and large it gets the job done when the job has been written to do its thing in Windows in a fairly competent fashion. I run Win XP on one of my boxes, I may upgrade someday when some particular need drives me to do so. It's not that I resist it, it's just that right now I've pretty well got that system whipped into shape, and I don't feel the need to repeat the work just to be on the latest and greatest.

When the time comes, I'll move on. That time isn't now.

My daughter, however, has her new Eee PC. I ended up being the one who got the machine started up for the first time today. I wanted to make sure it was functional within a time frame that would allow me to take it back to the store for a replacement if it turned out there was a problem. So I got to start up and use Windows 7 for the first time.

First Impressions

My first impression is that it's not all that different from earlier versions of Windows. The first image that comes to mind with Windows 7 is "new curtains in a miner's shack." It's still got that sort of clunky, crunchy Windows feel of how it does things, with some new art slapped in in those places where new art is easy to slap in. It doesn't feel all that new.

Of course, I think "new" is something the Windows audience felt they had enough of with Vista (which I found usable but somewhat more annoying than XP, and certainly no real improvement on its predecessor, at least for what I use it for.) So the retro feel may be intentional. Or it may just have been easy.

It's got a slight case of "I wanna look like a Mac"-itis, but not obsessively so. It still looks and feels like Windows, with half-melted icons being more the norm than when they first started appearing in the days of Windows 98.

Overall impression: Meh.

I won't be rushing to upgrade any time soon.

Snow Leopard

I'll preface this by saying that I think the user experience for Leopard has been a big step backward for the Mac. Tiger still sits at the top of the Mac OS X versions for me. Leopard's ability to deal with networking, both by itself and in conjunction with other Mac and non-Mac systems, is a big step backward from the "it just works" standard of Tiger.

Over the past few years, Macs have declined from being my multiple primary systems to being ancillaries in terms of my regular use. My little Eee PCs, originally purchased for use when travelling or at my easy chair, have supplanted my Macs. Given that I can buy 3 Eee PCs for the price of a single Mac, I'm in no hurry to go out and buy a new Mac.

(scroll down to skip Mac rants)

Add to that the fact that my current Mac systems are all replacements for hardware that failed under coverage by AppleCare. I bought my original systems at full price--well, I get the minimal educator discount. It meant something once, but my desktop I got as a refurb from Apple with no educator discount because it was cheaper than the educator discount. Apple had actually not solved the problem with the "refurb" when I received it. Fortunately I found it easily enough. The CTRL keycap was inverted on the keyboard and sticking, preventing the machine from booting until I pulled it off and put it back on properly.

That was the last of the G5 iMacs, and it was a great system for years. Then it started having problems. It had also had a problem I'd lived with for years--the headset plug didn't put out audio. I took it in to the Apple Store for both problems, having stated that it had both problems in every call prior, and stating so again in the store while the "Genius" was filling out the repair sheet. After about a week, Apple insisted my computer had no problems. I asked if they'd fixed the audio, they were ambiguous. I insisted that the system did have a problem that was causing it to go into thermal shutdown, even on moderately demanding app. I told them to keep looking. Some too-long period later they called back and told me they'd replaced the power supply. I asked after the audio. They said the audio output was fine.

I got the computer back, it ran great. But the audio jack was still dead. I'd given up substantial work time to go to and fro to the Apple store at the far end of Sacramento (the one in Roseville didn't exist yet), and I was ticked as can be about the audio jack still not working. When I called AppleCare they said there was no record, anywhere, of me stating that problem. I only said it on, like, EVERY call and interaction I'd had with them, repeatedly, with special EMPHASIS to make sure it didn't get lost in the face of the other shutdown problem.

(still ranting, scroll down to skip)

Apple refused to let me ship it back and forth for repairs, the way I have for the repairs for my PowerBook and MacBook (3 and 2 times, respectively.) The only offer they could give me was to replace it with a current model.

I should have stuck with the bad audio output. I've hated the new iMac ever since I've got it. Yeah, it's got "better" graphics chips, a Core 2 Duo processor as opposed to a G5, but the shiney screen shows me nothing but the window in my office. Fat load of good that does me. What am I supposed to do, work in a darkroom? My G5 worked great in the same location, this aluminum thing is an abomination. I often consider picking up a used older white iMac, and donating this thing to my school. Assuming I don't throw it out a window, first.

I suppose you can say that it was good of Apple to replace my systems. And it was. But I would much rather that the original systems just worked, or maybe even got repaired as I asked.
Both replacements are significantly worse than the original systems I bought in terms of usability. I say they're lower quality, too. Even though they contain newer technology components.

(end of Mac rants, you may safely continue reading)

So, I'm certainly no Apple fanboi. I've been distressed at the general direction they've gone over the past few years, though I think the Unibody laptops are a big improvement over the floppy sloppy Macbook they sent me to replace my third-time-broken PowerBook G4 (after much sturm and drang and wrangling over the phone over the course of several weeks, but that's another story.)

So...Snow Leopard.

Part of the reason I wanted it was that Leopard is limited in its video modes. My MacBook lives in my living room, since it's too fragile to use as a regular travelling notebook computer. It went back to Apple twice while it was covered under AppleCare for problems. I used that system with utmost care when I was going places with it. I put it in a padded case, didn't overload the case, set it with good airflow on a flat surface. It broke, not once but twice.

So now it's sitting on my entertainment center, pretending to be a much cheaper Mac Mini. So far, it's still working though I have to be careful since it runs hot as the devil--the airflow with the screen either closed or open is not nearly enough. It's a botched design.

OK, so Leopard and the older versions of Mac OS won't do a stretched display to fit my widescreen TV. The graphics chipset in the MacBook is certainly capable of it, but the OSes refuse to acknowledge this. I get 4x3 display resolutions listed for my TV, nothing else. I tried a third party solution. It hosed my system's display settings so bad I was afraid it was going to end up bricked. Fortunately, I managed to recover by booting off an external backup drive and get the system restored. And I got rid of the third party solution.

Last week I wandered into the Apple Store. I've been considering Snow Leopard for a while. Whenever I gripe about Leopard my other Mac user friends tell me I need to go to Snow Leopard. They're short on details, however, so I've been dragging my feet. I've heard such things before.

I walked up to one of the Macs in the Apple Store, one hooked up to an external display (not a TV, though. I didn't see anything with a VGA adapter on it) and opened up Display Preferences. I see the option "1024x768 (stretched)". Aha, I think, maybe now I can make the Mac use my widescreen as a widescreen without looking entirely wrong. (Isn't looking good supposed to be one of the Mac's strong points?)

(minor Apple Store rant in next paragraph, but it's brief)

That, with what else I've heard, and the relatively low price, had me picking up a copy of Snow Leopard at Fry's the other day. No, not the Apple Store. I don't know what was up there, but when I walked up to the front of the store looking like I wanted to buy something, none of the Apple associates even so much as looked at me. I have no idea what was going on. I considered banging on the counter then yelling "I want to give Apple my MONEY, does anybody here care?", but I decided to leave rather than risk an encounter with the mall police. So I closed the deal at Fry's a few days later.

(I finally get to the Snow Leopard install here!)

The install went pretty well, except when I got to the "optional installs." I felt like the installer was rushing me into doing something to my drive that I didn't even know what it would be. I hit a point where I was afraid to click to move on any further, since I expected it to give me a choice of what software packages I would and wouldn't want to install. I felt like it was going to go ahead and put who knows what on my system without my say-so. So I stopped and hit Firefox to find out what was up.

It turned out that I did get a choice, two screens past the point where I felt like it was going to commit me to installing 30 pieces of trial crapware on my system. There weren't 30 pieces of trialware in the package, it was the sort of thing I expected, X11 and the base Mac apps like Calendar and so on. But from the point where I balked, I couldn't tell that.

I also couldn't tell if I should have selected things I already had on my system, like X11 and the new Safari. Had it upgraded the old packages during the main OS install or not? I had no idea, and ended up just selecting Rosetta, figuring I could check version numbers on the other stuff and come back later.

So far as I can tell, I have the latest versions of the other software, but within the installer I had no way of knowing that based on what I was being told by the installer and the choices it gave me.

Once Burned, Twice Shy

I'm pretty goosey about OS upgrades on the Mac. An iLife upgrade on my wife's G4 tower a few years ago turned a fine system into a haunted system that never worked properly ever again. It left her with a bunch of corrupted family video files, and stopped her in her tracks from doing a wide range of video related tasks.

At this point Snow Leopard is pretty well indistinguishable from Leopard. There's a slider on Finder to adjust the sizes of the icons in icon view, but otherwise Finder still appears to be as stupid as it's ever been.

Video Modes?

And the video modes. No luck. Sure, I can stretch the display on my built-in LCD display. Whoop de doo. But I'm still stuck with nothing but 4x3 aspect ratio display options on my TV. This infuriates me. I've been able to make this adjustment in Windows since Win98, possibly even Win 95. The chipset is capable of it. The computer shouldn't need the screen to tell it what aspect ratios it has, it's the computer that does the stretching, not the TV. I'm going to call AppleCare and ask to make sure I'm not missing something, but at this point it looks like my MacBook won't even be up to the job of media computer.

Maybe I'll trade my daughter my MacBook for her new Eee PC, and put that on the TV instead.

Snow Leopard Overall Impression: Bleah.

Here's a Quarter, Kid. Go Get Yourself a Real Computer

Where's my Amiga 500? I need some quality computer time. The 21st century is waaaay over-rated.

Does it say anything that I get more excited over new browsers these days than new OSes?

A Young Person's Review of The Mote in God's Eye

2010-08-27T20:58:00.000-07:00

My daughter read this SF classic and loved it, so I've asked her to do a review for my website, since I thought it'd be interesting to have a review of this book from someone who wasn't even around when it was written.

I have occasion to wonder if some of what I consider "classic" is material that's as doomed to be forgotten as some of the great novels of a century ago or more. I hate to think it's that ephemeral, but I'm not in a good position to judge. My daughters don't read a regular diet of the books I enjoyed when I was their age (but then, I was considered pretty odd for my tastes when I was that age, too), but they do enjoy picking up some 70s-80s SF to spice things up and break up the mangas a bit. Sometimes they even discover where things they read about in the mangas "come from."

Check out the review, and stay tuned. My younger daughter ate up Ringworld, so I'm trying to get a review out of her, too.

Making the Mac Speak in Java

2010-08-26T12:25:00.000-07:00

The Mac "say" program is an endless source of fun and mischief. In class, I like to make the Macs talk to the students sometimes using the say command from an ssh login from across the room.

While preparing an article on calling system commands in Java, I decided to combine that with the Mac "say" command in my Simple Video Game Kernel.

I'm posting this here, since I avoid posting platform-specific code at my Java programming blog.

Give it a try, if you've got a Mac handy, and enjoy.

/* A simple video game style kernel
   by Mark Graybill, August 2010
   Uses the Timer Class to move a ball on a playfield
   30 times per second. Add additional "players" to 
   the playfield with appropriate control routines to
   make a full game.

  This version adds speech to the poor little ball getting
  bounced off the walls. Mac-only, I'm afraid.
*/

// Import Timer and other useful stuff:
import java.util.*;
// Import the basic graphics classes.
import java.awt.*;
import javax.swing.*;
// import java.lang.Math;

public class VGKernel extends JPanel{

// This is not a recommended coding practice, just a shortcut.
public Rectangle screen, ball; // The screen area and ball location/size.
public Rectangle bounds;  // The boundaries of the drawing area.
public JFrame frame; // A JFrame to put the graphics into.
public VGTimerTask vgTask; // The TimerTask that runs the game.
public boolean down, right; // Direction of ball's travel.

// Create a constructor method:
  public VGKernel(){
    super();
    screen = new Rectangle(0, 0, 600, 400);
    ball   = new Rectangle(0, 0, 20, 20);
    bounds = new Rectangle(0, 0, 600, 400); // Give some temporary values.
    frame = new JFrame("VGKernel");
    vgTask = new VGTimerTask();
}

  // Create an inner TimerTask class that has access to the
  // members of the VGKernel.
  class VGTimerTask extends TimerTask{
    public void run(){
      moveBall();
      frame.repaint();
    }
  }

// Now the instance methods:
  public void paintComponent(Graphics g){
    // Get the drawing area bounds for game logic.
    bounds = g.getClipBounds();
    // Clear the drawing area, then draw the ball.
    g.clearRect(screen.x, screen.y, screen.width, screen.height);
    g.fillRect(ball.x, ball.y, ball.width, ball.height);
  }

  public void moveBall(){
  // Ball should really be its own class.
    if (right) ball.x+=ball.width/4; // If right is true, move ball right,
    else ball.x-=ball.width/4;       // otherwise move left.
    if (down)  ball.y+=ball.height/4; // Same for up/down.
    else ball.y-=ball.width/4;
    if (ball.x > (bounds.width - ball.width)) // Detect edges and bounce.
      { right = false; ball.x = bounds.width -  ball.width; 
        try { Process p = new ProcessBuilder("say", "-v", "Ralph", 
                         "[[pbas +18]] [[rate +70]] Ow").start();}
        catch(java.io.IOException io){}
      }
    if (ball.y > (bounds.height - ball.height))
      { down  = false; ball.y = bounds.height - ball.height;
        try { Process p = new ProcessBuilder("say", "-v", "Ralph", 
                          "[[pbas +18]] [[rate +70]] uh").start();}
        catch(java.io.IOException io){}
      }
    if (ball.x <= 0) { right = true; ball.x = 0; 
        try { Process p = new ProcessBuilder("say", "-v", "Ralph", 
                         "[[pbas +18]] [[rate +70]] arg").start();}
        catch(java.io.IOException io){}
    }
    if (ball.y <= 0) { down  = true; ball.y = 0; 
        try { Process p = new ProcessBuilder("say", "-v", "Ralph", 
                          "[[pbas +18]] [[rate +70]] uh").start();}
        catch(java.io.IOException io){}
    }
  }

  public static void main(String arg[]){

    // Create a Timer object and an instance of VGKernel
    java.util.Timer vgTimer = new java.util.Timer();  
    VGKernel panel = new VGKernel(); 
    
    panel.down = true;
    panel.right = true;
    panel.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    panel.frame.setSize(panel.screen.width, panel.screen.height);

    panel.frame.setContentPane(panel); 
    panel.frame.setVisible(true);

    // Set up a timer to do the vgTask regularly.
    vgTimer.schedule(panel.vgTask, 0, 20);
  }
}

The funny looking [[pbas +18]] type things in the "say" commands are inline commands to the Mac speech synthesizer to change the characteristics of the voice. You can omit these if you want to make the commands easier to read, then add them back in to see what affect they have (or play with the numbers.) You can find out more about using the Mac speech synthesizer at Apple's developer site.

Pathfinder RPG: Advanced Player's Guide Quick Look

2010-08-25T16:20:00.000-07:00

I just bought the Advanced Player's Guide for the Pathfinder RPG (from my favorite shop, see above. Chris loves to do phone and internet orders as well as walk-ins like me.)

I wasn't originally planning on buying this book, at least not for a few months. To be honest, the preview material sort of put me off. The art is part of that. The technical execution of the art is as good as Paizo's art has ever been, but the character design has veered deeper into the kewlio. I kvetched about the art a bit before, in my Pathfinder RPG review, but this is just a bit too much for me. It detracts from the material of the book. I hope we won't be seeing a whole lot of these characters in future materials, the way the original characters have been used over and over and over again (Paizo does get their mileage out of their art and their character designs, that's for sure.)

So why did I drop the hardback retail on this book?

The first thing I was looking for from a new book is well designed player classes.The Alchemist, the Summoner, and the Witch are all classes I like. The Cavalier, Inquisitor, and Oracle don't do it for me. While new classes was the main thing I was looking for from this book, there turned out to be some surprises that finally tipped the balance for me to get this book. First, a look at the classes.

Alchemist

I have a soft spot for Alchemists. A friend played a very interesting Alchemist in the first campaign I played in. The character class came from The Strategic Review (or it may have become The Dragon by the time the Alchemist appeared, I don't recall.) He did a great job with that character, and when he lost his arm--only to have it replaced by a tentacle due to a botched regeneration--it made the character more interesting. I added the Alchemist to my campaign, and I've had the class ever since. Here's my latest version for OD&D. So far, the Alchemist in the PFRPG APG looks good. The power level looks good for the overall level of the game, and it's a flexible enough class to be good for a lot of adventuring. I'm sure I'll have more to say about it in the future.

Summoner

The Summoner is another type of class I like. Ever since playing Metagaming's Microgames Melee and Wizard (both part of a larger game called The Fantasy Trip), the idea of a mage who acts mainly through indirect spells that call up minions and items has appealed to me. I've tried designing several such classes for OD&D, but haven't been happy enough with them to use them in my present game (largely because it takes a lot of time to balance such a class.) The Summoner class of the APG seems a bit limited, since it's mostly monster-type summoning so far as I can tell at first look. I need to spend more time with the spell list to see if there are any of the "summon a mondo weapon for your buddy" type spells as well to round out the class a bit. What I've seen so far looks good.

Witch

The Witch is also a class that goes back a long time. There were two of them in early articles of TSR and The Dragon that I recall. I also built a pretty good Witch/Warlock class myself that I ran for many years in my game. The Witch class here looks like a sort of arcane druid class. It looks like a good option for players who want this sort of slant to their character, when one of the other caster classes doesn't appeal to them.

What Didn't Work for Me

I'll try to be brief about the three new classes that don't appeal to me; Cavalier, Inquisitor, and Oracle. Cavalier and Inquisitor look just too limited to be of general use. It's too early in the game's publication cycle to start putting out such limited character types, IMO. And where the appeal is for the Oracle, I don't know. It's a pretty blah looking class, particularly next to the extremely well designed Cleric class for this game. The Inquisitor looks like it's as much of a party pain in the tookus as the old-style AD&D Paladins were, possibly worse. And the Cavalier just looks like a gimped fighter. I'll look at them some more, there's plenty of possibility I've missed what the magic is to these classes. Right now I consider them dead weight.

The Surprise

What I wasn't expecting but was pleased by is the additions to the core classes from the original Core book. I wasn't expecting much but fluff, but from my brief look so far, it looks pretty meaty. It was enough to get me to lay down my cash, along with the three classes I like.

The Downside

The BIG downside is that there's now another book to be rifled through at the table. "Which book was that in?" will become a common question. It drives me crazy. One of the things I really liked about PFRPG was how great a game it is with just two books. If this was just one more GMs book, it wouldn't be that big an issue. But it's a player book. Which means it'll be getting passed around the table along with the Core book. "Where was that ability?" "Where was that feat described?" Sigh.

As it is, I don't plan on rolling the new rules into the game until some time down the road. If someone has to roll up a new character, I'll let them draw from this book in the meanwhile, but otherwise I'll wait a bit until my players have more of what's in the core book well known to them. In the meanwhile, I'll be reading and familiarizing myself with this new book.

One More Factor

Another thing that pushed me toward buying this book now is my 15 year old daughter. She really got excited by this book. She gives it two thumbs up, with no reservations at all. She likes everything she's seen in it.

PFRPG Roll Call

Here are the books I've bought so far and what I think of them:
Core Rulebook: Five Stars. Paizo has made d20 really smooth and fun to play.
Bestiary: Five Stars. The best monster book I've ever had, bar none. And remember, I was on the waiting list before the original Monster Manual came out back in the 70s. It makes a GM's life a good one. Get it even if you're doing some other d20 game. You'll wish they were all this good.
Gamemastery Guide: Three Stars. Only get it if you're a new GM, or if you see some material in it you think will be particularly useful to your campaign, like the NPC generation rules or the city material. If you're a new GM, it'll help get a campaign rolling quickly.
GameMaster's Screen: One Star. Total Fluff. Well made physically, but the reference charts on it aren't the ones you really wish you had. Avoid unless you want something really solid and really expensive to tape printouts of the charts you actually use to.
Advanced Player's Guide: (Ranking Awaiting Further Looking) Get it if you want to spice up your campaign past the core material. Otherwise, wait until your campaign has matured a bit. I like it pretty well, but I think they should have put in four really killer classes rather than three good and three specialty classes probably not for all campaigns.

Prestige Classes:
The APG has prestige classes in it, but I don't mention them here because they don't get used in my campaign except for NPCs. I tend to top out the characters' lives before they become too über, at about tenth level or so.

Browsing the Web with an Atari 2600?

2010-08-24T18:46:00.001-07:00

I posted an entry about Web Surfer, my new cartridge for my Atari 2600 over on my other blog by accident last week. It was supposed to be posted here.

Browse the Web with Your Atari VCS 2600.

Nevertheless, there are not one but two, count 'em, two pages of information over there. Apparently I was a bit too subtle in my placement of the link to the second page, and almost nobody who has visited there has seen it. So I added a message next to the image (the picture at the bottom of the first page) that acts as a link to the second page. It's the "how to" page--the first one is just sort of a "gee whiz" page. I guess I fail at information organization.

Have a look. If I still get nobody getting there now, I'll use 36 point type and the <BLINK> tag next time. If that doesn't work, we'll, then I'll know for a fact that I should just bury my mistakes and move on. ;)

The High Frontier by Gerard K. O'Neill as Seen from Year 2010

2010-08-18T04:56:00.000-07:00

I've posted a new book review of Gerard K. O'Neill's The High Frontier as it appears today.

I read this book back in the 70's, but haven't read it in over 25 years. I was almost scared to see what it would look like in the light of 2010.

Have a look and see what you think. Impetuous enthusiasm or something that could really be real?

Read it for Yourself

New Wireless Keyboard: Siig Multi-Touchpad Mini

2010-08-17T16:27:00.000-07:00

I picked up a new keyboard to use in the living room yesterday. It's a Siig wireless model with a touchpad in it. I wanted to give up the mouse, and just get everything in one place for this work location. I'll do a full review on it later, once I've had a chance to get used to it.

So far, it's going well. They keyboard itself is very nice. Most of the mini keyboards I've tried have keys that are too small, or keycaps that are too close together at the top, making it easier to fat-finger them when typing in a lap. The Siig has well separated keys of good size. The Enter key is a little smaller than I would like, and there's a Fn key in the lower right corner where my CTRL key is, otherwise I'm pretty happy with the keyboard.

The mouse keys are recessed just a bit too much, and could be a millimeter or two taller (from front to back of the keyboard) to make them easier to hit.

My big open question at this point is whether I can learn to live with tap-to-click on the keypad. For the first few hours, I had no problems. Now it seems like I'm always clicking when I don't want to. Personally, I despise tap-to-click. I like touchpads for pointing, and scrolling. Clicking is for buttons.

Maybe I can learn to live with it. My daughter loves tap to click on her Eee PC (I turned it off on all of mine.) I haven't found a way to turn it off on this keyboard--the control in the OS's options controls the computer's inbuilt touchpad, but not this one. I suspect all the translation from touchpad to clicks is happening inside the keyboard itself, so the OS may have nothing to say about it.

I'll come back with a more full review after I've had another week or two with this keyboard.

Meanwhile, I can now sit in a number of different places while using this computer.

Whatever Happened to the Eee Keyboard PC?

2010-08-16T15:02:00.000-07:00

I like my ASUS Eee PCs. I've got three of them. They've displaced a full size PC laptop and a MacBook (now relegated to being my TV computer) as well as a desktop system. They're rugged as heck--I throw them right into my book bag when I take one (or more) to school. They work well, and I especially liked buying them with Linux pre-installed and configured for the hardware. Though now ASUS appears to have been strong-armed into shipping with just Windows (market demand my foot--like anyone trying to buy a 901 with Linux on it when it was first released would believe that!)

A new model was shown around, a unit that has the entire system built into the keyboard. Expansion ports, connectors, and a touch-screen display. You can see it at slashgear and on Steve Chippy's YouTube video. I thought this was pretty darn slick. I was ready to buy at least one, probably two.

Then they just sort of dropped off the face of the map. They don't appear nor are they mentioned on the ASUS Eee site.

And I haven't heard any follow-up reports since those glowing announcements telling me I was going to be able to buy one last June.

The Eee Touch and Eee Box just don't do it for me. The Eee Keyboard was the killer box. I can't hardly think that I'm so very odd that I'm the only one that was ready for the return of the keyboard console computer.

What do you say?

p.s. ASUS: If you want to recover some costs by selling off a couple of functional prototypes, drop me an email!

Greenfoot's Greenroom: What a Bonanza!

2010-08-13T17:42:00.000-07:00

I finally got around to registering for The Greenroom, a support area for teachers using the Greenfoot framework for Java in their classes. All I have to say is, Wow!

If you're a teacher using Greenfoot, or thinking about it, take the time to sign up for access. Access is limited to those who can show some bona fides to show that they're teachers, not sneaky students trying to wreck the teacher's lesson plan. ;)

That's what kept me from signing up for some time, I just didn't take the time to dig up something with my name on it at my school's website to show my status. Well, I finally took the time to do it, and now I wish I'd bothered a long time ago!

The resources available include a wide selection of very well presented lessons, exercises, and information on using Greenfoot with Eclipse, etc., etc. Then there's the discussion boards. I follow the Greenfoot and BlueJ mailing lists, but the Greenroom discussions have an extra dimension to them, particularly from the teacher's perspective.

If that's not enough, that's also where to find the announcement of the forthcoming Greenfoot 2.0! My excitement about Greenfoot 2.0 is the new editor, with syntax highlighting and code completion. I can't wait to get my hands on it, I'll post about it when I do.

Class Projects: The Good, the Bad, and the Future Value

2010-08-12T11:31:00.000-07:00

In my prior post about the student projects posted from Cornell's ECE 4760 program, I mentioned how nice it is, as a teacher, to see these reports and get a sense of how what I do with my classes compares. Class projects have their limitations, but they're tremendously valuable for the students.

The Good Parts:

Allows students to develop and build on their own ideas.
Lets them exercise the knowledge they've gained.
Gives opportunities to discover gaps in their knowledge.
Introduces time and resource constraints to practical work.
Teaches teamwork skills.
Opens up "teachable moments" not accessible through regular classwork.

The (sort of) Bad Parts:

Time and resources are never sufficient.
Substantial amounts of effort can be expended on fruitless effort.
Non-self starters can falter easily.
Much of the class grade rests on work patterns with which many students are unskilled.
Teams don't always gel.

I say "sort of" bad, because these are the same sorts of problems that are encountered outside the classroom. In the classroom, the cost of failure is a less than sterling grade--and not even necessarily that. Failure in the classroom is not the same as commercial failure. A non-working project does not necessarily result in a poor grade (though one that works as planned will usually garner a better grade.) The classroom is a good place to be pushed and challenged.

The Future Value:

Lessons learned when doing projects are often more valuable outside the classroom, in terms of time spent, than much else that is done in the classroom.
Recognition of the value of people and communications skills alongside technical skills.
Understanding that technical work must be accomplished to have success, even in the face of uncertainty.
Learning to build on strengths, rather than be halted by shortcomings.
Experiencing how great the gap is between a technically successful demonstration and a finished product.

The road to a finished product is seldom traveled to its end in a class project. There just isn't time in most class schedules, even if the students spend time outside class working on the project. However, a sense of the length of that road is obtained, I find. And a new appreciation for the effort that goes into the "second 90%" of work on a product is developed.

In my class, the teams get a chance to see what happens when actual users lay hands on the project results as well. The developers of a program have to watch silently as members of another team try to use their product. They get to learn more in 20 minutes than I could give them in hours of lecture.

The best part of class projects, in my opinion? It's a lot more fun than limiting a class to assigned classwork. I try to spend as little time on teaching the necessary material as possible before setting my students loose to discover on their own. It's something that not only do I enjoy more, but my students, so long as they keep the project in perspective, can enjoy a lot more than assigned work. It's very jarring for some to be set loose this way, but once they're helped over the hump everyone has a really good time with it.

Plus, they get to have an actual thing out there with their name on it. Something they can point to and say

"I did that."

Cornell University's AVR Projects: Hobby Inspiration, Teaching Inspiration

2010-08-10T16:10:00.000-07:00

The ECE 4760 class at Cornell University posts their student projects for the class. There are several years' worth of class projects there, of all sorts. The class uses the AVR microcontroller, a very nice platform that I enjoy using both professionally and personally.

For personal use, I really like the Cornell site since it not only gives me ideas, but it lets me see implementations others have made (or attempted) of ideas I have for my own projects. The reports are usually sufficiently detailed that I can either replicate or build on the students' solutions to particular problems.

Teaching Inspiration
I also find the site very inspirational as a teacher. Seeing the sort of results, rescopings, and occasional failures of the class projects undertaken by the students in this class is very valuable to me. I end my high school computer class with a project each year. My students go through the same set of compromises, adjustments, and triumphs as the students in the Cornell ECE 4760 class. While I know it's normal, it's also reassuring to see the "raw data" from another class in the form of the students' reports on their projects. It gives me a sense of where other instructors are in the scale of setting challenges before their students versus the results. Clearly the Cornell class is a challenging and dynamic class. The projects they undertake are exciting, and the results, even when less than hoped for, are exciting as well.

Plus, it makes me feel good to see that the much lower level and smaller scale challenges I present my students produce similar results. I can only hope that some of them get to go on to experience something like the ECE 4760 class in the future, and that I've helped prepare them for such things.

Java, Javascript, and the Installation Hurdle

2010-08-04T13:22:00.000-07:00

For the past three years I've been teaching high school computer classes while using Java to teach the basics of programming in class. My usual routine is to teach HTML and CSS in the first semester, which provides the students with many of the basic skills of programming. Then in the second semester we start actually programming with Java.

The past two years I've taken advantage of the Greenfoot framework for Java. It eases the use of graphics and sound in Java programs, but more importantly it provides a visual representation of classes and objects. This greatly eases the burden of teaching what object oriented programming is all about, as well as demonstrating its advantages.

My reasons for using Java are several. Briefly, it's multi-platform. It's a "real" language, in that it is used outside the school and professionals are employed to use it. It incorporates the available facilities of the system, including graphics and sound, natively.

One of my hopes for my students is that after using Java in class, at least some of them will use it outside class as well. Unfortunately, for many of them the installation process has been a roadblock to doing this. Particularly in Windows, where an extra step has to be performed to add the Java SDK to the system's path. The students with Mac OS X at home are lucky, they don't have to install the SDK, it comes with the OS. The Linux users are usually capable of managing it for themselves. But about 80% of my students are under Windows outside of class. And the Java SDK install isn't what they're used to.

One potential solution to this would be moving to Javascript. There's no installation barrier there. One reason I've not used Javascript in class is that graphics subsystems like Canvas and SVG are not uniformly available. Even when IE9 comes out as a regular product next year, those students with Windows XP systems at home (about 75% of the Windows-only homes are running only XP, based on my surveys in class), this problem won't be entirely solved. The difference here is that the install of a second browser is a lot easier than a Java SDK install.

The installation barrier won't be the only thing my choice of language in class hinges on, but it's certainly a significant factor. Exactly why the Java SDK install has remained so hostile to Windows users is unclear to me. It smacks of elitism on the part of Sun/Oracle (if you can't hack the install process, we don't want you using it), but then the old saw about not ascribing evil intent where simple incompetence will suffice comes in. Maybe they just don't think it's a problem.

I expect to at least introduce Javascript this year as part of the HTML/CSS segment. Whether I do so and how deep we'll get into it will depend heavily on the character of the class--the chemistry of the students in any given class can make things vary a lot from class to class. Sometimes it's a struggle to get past <html><head><title><body>, other times I find them getting ahead of my lecture by several classes during one open work period.

Another factor in my willingness to consider using Javascript as the primary language in class is the advances the language has made recently. The ECMAScript Edition 5 specification is a big improvement on earlier specifications for the language. Likewise, the viewpoints of Douglas Crockford have influenced my impression of the language and its use.

If you're interested in Javascript, I highly recommend his book: JavaScript: The Good Parts.

Pathfinder RPG by Paizo

2010-07-29T10:53:00.000-07:00

Paizo's Pathfinder RPG is a game that I just keep liking more and more. Until now, I haven't had much use for d20 games. But Pathfinder really seems to hit the balance just right. As a DM/GM/referee I really like the Paizo books.

I started playing role playing games with a friend who started running a game based on photocopies of photocopies of Gary Gygax's hand-written notes. I'd been playing war games for a few years, and enjoyed D&D a lot as well. Over the years, I've run or played in games using all sorts of systems. Most of that time I've run a game based on the original D&D 3 book set and pieces taken out of its supplements and the very early D&D magazines. Other than original D&D (OD&D), the original Runequest has been my favorite set of game rules.

When D&D 3.0 was being developed, friends of mine were play testers. The revamp of the game sounded very, very promising. AD&D had become far too Byzantine for me, I skipped AD&D2 entirely. When the d20 rules for D&D3 came out, I started a game using them. I was excited, I was ready for the change and wanted to have a game that'd roll along as easily as OD&D but be somewhat more fleshed out.

Unfortunately, things never really gelled. The game just didn't run all that well for me, and my players were ready to give up. About that time 3.5 came out. Hopes high, I checked it out. Unfortunately, it took what wasn't working in 3.0 and made those things worse, not better. It was more complicated and institutionalized the power creep that had already entered the game. I went back to OD&D for my fantasy games (for SF I was using the original Traveller rules I bought in 1977.)

The appeal of what d20 represents was still there, but at the table the game just wasn't working for me or my players. The system made it about impossible to bring in new players, the life of any long-running game. With OD&D I could get a new player in the game making confident choices for their characters in an hour or less. Yeah, I was writing my own adventures and content no matter how little time work and the rest of life left me. Yeah, players never quite knew how things were going to go when they were outside combat and I was making up resolution systems for their actions on the fly. But we could jump in, play, and have fun easily and quickly at the table. I could write really simple software to help me generate encounters and otherwise prepare for a game. I had over 30 years worth of notes backing up my game.

Then came the announcement of D&D 4.0. No big deal. I'll just keep rolling along with OD&D.

But some folks weren't ready to give up on d20. It had worked for them. The "ecosystem" thing that the OGL promised had actually happened. That ecosystem thing was something I wanted part of, in spite of my problems with d20. Then leadership happened. The folks at Paizo decided they weren't just going to give up the stake they had in d20.

I downloaded the Pathfinder RPG beta document, and immediately liked what I saw. Non combat skill rules were simplified. The rogue/thief class had some power back. d20 rules problems were settled with sensible corrections. As a beta document, it didn't have all the introductory material that would be expected in a finished product, but it definitely was a big step toward closing the gap between me and d20. I ran some skirmishes with small groups of players and played around with the rules solo. It was encouraging.

Another plus was that the core rules would be published in 2 books, a rulebook and a book of critters for the game. Getting soaked by the tradition of putting things in 3 books was getting old, especially when five hundred add-on books follow, and other systems were regularly coming out with a single core book. Add to that that with border art, incidental art, and other foo-foo each page of each book dedicated less than one third of its space to actual rules, and it was time for a revolution.
I picked up the Core Rulebook as soon as it was available at my friendly local game shop. I bought it to read, not to play. I had an active Traveller game going using the new rules from Mongoose. But, as with the beta, I ran some solo stuff to sort of try out the rules and I ran some simple skirmishes with my daughters just to get some experience with live players.

I liked the changes Paizo had made a whole heck of a lot. The changes are few, and subtle, but the effect on play are tremendous. It's what d20 should have been.

Then the Bestiary hit the streets. I picked it up, too. The free previews had spurred my interest, plus this way I'd have a full set of core rules in case I wanted to play for real someday. Not that I couldn't have used any other d20 book of critters, like my D&D 3.0 Monster Manual. But among the other things I'd liked, a set of sample stats for a typical critter is a part of each listing in the Bestiary. If you don't want to have to roll dice for each random encounter, now you can just use the prefab creature straight from the book.

Finally, my daughter decided to take a sabbatical from running her Rules Cyclopedia based OD&D campaign. Her players wanted to keep their characters going, so I agreed to pick up the game. My little skirmishes and pseudo-encounters had given me confidence that I could run Pathfinder, so I converted the characters and started running a Pathfinder campaign.

I took advantage of the d20 ecosystem and pulled "Hollow's Last Hope" from the internet, touched it up, and put it into play. The first session I used a few OD&D mechanics to keep play rolling (my players didn't even notice.) I looked up the rules I was fuzzy on between games, and the second session went even better, and hewed closer to the rules as written as an extra added bonus.

By the third session it was as easy for me to run the Pathfinder RPG as it is for me to run OD&D. This is as opposed to D&D3.X, which was still a rough struggle for me even after a year and a half. Granted I have the D&D3.X background as I'm coming to Pathfinder, but really that's not the issue. Any more than my Runequest experience affected my ability to run Lejendary Adventures or any of the other skill-based systems. Rules either run well or they don't.

By itself that's good, but what really sells me on a game system is how it affects the players. That's what sold me on Mongoose's Traveller after over 30 years of running "Classic Traveller" (which I still stir into my Mongoose Traveller game.) The players felt more empowered by MGT, they got into the characters and adventures faster and more deeply. Classic Traveller is still great, and it meshes well with MGT, but when I run a science fiction game it's Mongoose's rules that are the core now.

Pathfinder had the same effect on my players relative to OD&D. The non combat skills set now assisted the players, rather than confusing them. There is enough definition to make them feel empowered, but its simple enough they aren't overwhelmed or confused. It's enough, and not too much. That's hard to do. Paizo did it.

A word on the art. Art has a pretty strong effect on me when I'm reading those rule books. I try not to let it happen, but it does. As much as I like the Mongoose Traveller rules, the art puts me off. I end up covering it with my hand so that I can read the rules on many pages. I roundly hated the art in the TSR d20 books. The border art, the character art...I hated it all.

I dislike the Paizo art a whole lot less. It still comes across as kewlio, but it's not oppressively so. The technical execution is definitely a big step above the TSR book art. Hackneyed as the characters and scenes are, I roll my eyes at it a lot less than I do the TSR art. It's decorative, rather than obnoxious. The TSR d20 books would be better as nothing more than black text on white pages. The Paizo books would be diminished by the loss of the art.

In a world where over the top, overly embellished fantasy art has become de rigeur, the Paizo art is the best of the breed I've found. It's not my cup of tea, but it doesn't make me grit my teeth and cover half the page with my hand as I try to get some rule into my head.

Bottom line, I like Paizo's Pathfinder RPG. A lot. I like it more the more I use it. I feel like the money I've spent on the game (aside from the GM screen*) is well spent. My players are having fun, even the one that doesn't like fantasy games. I can run a smooth game that swims along nicely. The power levels are high compared to D&D3.0, but at least they're well balanced and so far appear pretty well stable. Thumbs up.

I can also recommend the Game Mastery Guide, though it's not essential by any means. I got it strictly as a luxury, and it's been a good read. If I ever feel the need for adding a bit more structure to my cities, I'll probably use the material in it. Most of the material in it is aimed at a newer DM, or one moving from using prepublished modules to buillding their own campaign. Even as a DM with over 35 years of experience I'm enjoying it, but it hasn't really affected my game yet.

Speaking of art, the cover almost put me off buying this book. The guy on the cover looks like he's the Munchkin Your Mother Warned You About. Again, the art's technical execution is excellent, but the subject it trite and overworked. But you know what they say about books and covers.

* Now that I've said that I don't like the GM Screen, I guess I'd better explain it. The construction and materials of the GM screen are top notch, but as a game reference aid it sucks rocks. The Paizo people would do well to go back and look at the contents of the GM screen for "The Classic Dungeons and Dragons Game" box set. It's the most useful GM screen ever made, bar none.

Ampro Little Board Plus Z-80 Computer

2010-07-06T19:16:00.000-07:00

I've built a small website about the Ampro Little Board Plus (Z-80) computer, with a section on what I've done with mine.

My Ampro Z-80 Computer, as it was first set up, loose on my kitchen table.

I've got scans of old Ampro advertisements, as well as scans of ads for the system's software. There are pics of my system, and where and how I got it set up.
Have a look.

Here are some past posts I've done on this system:

Bringing Up the Ampro Little Board Plus
How I first brought up the Ampro.
Retrocomputing with CP/M, and Only CP/M
Using the Ampro with nothing but the included software. ED for editing, ASM for compiling assembly code.
8085 Homebrew Concept
How using the Ampro to program in 8080 assembly code inspired my 8085 project.
Retrocomputing Summer
Setting up the Ampro in a new location, with a new terminal.

Retrocomputing Summer

2010-06-30T20:30:00.000-07:00

Aside from some astronomy, I've been spending a lot of my free time this summer on some retrocomputing projects. In particular, I've been working on my homebrew 8085 single board computer and my Ampro Little Board Plus Z-80 systems. Alongside that, I've been trying to fit a new computer that's similar to a COSMAC Elf into an Altoids tin.

Lee Hart's 1802-Based Mini-Microcomputer: The Membership Card.

Retrocomputing in Your Pocket.
Lee Hart's Membership Card computer. It's based on the RCA 1802 microprocessor, and it's a close cousin to the COSMAC Elf computer (Google it, if you don't know about it!)

Lee Hart gave me a set of printed circuit boards for his new Membership Card computer last fall. It's a really neat design. In essence, it's a COSMAC Elf that fits in those handy little enclosures, Altoids tins. It can take up to 32KB of memory, in either a ROM or a RAM, and includes a full front panel with toggle switches and LEDs displaying binary. If you don't want to go quite so hairshirt, you can connect to a PC over a serial port, or build your own front panel card. I'm thinking of going with a hex display and hexadecimal keypad in a future build.

Meanwhile, I'm trying to fit my Membership Card into its tin. I think my switches are too tall, so I'm going to have to make some other accomodations.

The tin doesn't quite close up. My interconnect between the PCBs may be too tall, or my switches aren't laying as low as Lee's did. It's only about 1.5mm, but it's enough. I'm working on Plan B now.

My 8085 Handheld Single Board Computer Project

My first shot at a front panel layout for my 8085 computer, laid out on acrylic sheet to make it easy to see what's where.

I've been working on my new 8085 computer project for a few months now. It's a new-design retrocomputer that's easy to build. I have the project designed so that a builder can put it together a little bit at a time, and test it thoroughly at each stage. That way you don't need to put together a bunch of parts then see if it all works at the end, and then wonder what's wrong when it doesn't all work together.

Each step of the project adds just one to three new pieces to the computer. The complete computer is only twelve integrated circuits, plus resistors, capacitors, and other small parts. It can be built with only eight ICs, if you want a simpler version that gives up a couple of extras. These can always be added in later, if desired. The real key to the project is that it provides a complete, functional 8085 system similar to the SDK-85 development system that can be built up from simple parts that are easy to understand and use in programs.

Most of my work lately, other than playing with software and deciding how I want the programmer's interface to work in its operating system, has been on the front panel of the computer and its enclosure. I want it to be something that someone with minimal tools, and even without power tools, can build from common materials available at an ordinary hardware store. I also want it to be attractive enough to show off after it's built, not something that looks like it belongs in a junkpile.

The partially-complete Masonite face panel of my 8085 computer.

I've nearly finished the third and final version of the face panel. I learned some things while making the first two that made me keep trying again. Fortunately, nobody else will have to go through three tries to get it right. I'll soon be posting the instructions for constructing the nice version of the front panel, and the enclosure, on my website. After trying acrylic and metal, I decided to go with Masonite (hardboard) as a material that anyone should be able to work and that can be made to look professional, even with hand tools. Masonite is an old friend of mine, I've been building enclosures out of it since the 60's, when I had nothing but unpowered hand tools, and very few of those, to work with (Back then I cut my panels with steak knives!)

Since posting details on the 8085 construction project takes about 3 times as long as doing it, I've been holding off on doing an update of the project on its site until I have the enclosure complete. Now I'm almost done, so an update will probably occupy the later part of my summer.

Ampro Little Board Plus Z-80

My Ampro Little Board Plus, in its original incarnation. A pile of parts on a kitchen table.

I first constructed my Ampro system as a mass of loose parts and cables on my kitchen table. The Ampro is a single board computer based on the Z-80 processor that includes serial and parallel I/O, 64K of memory, and a SCSI controller all on a board that's sized to piggyback on a 5-1/4" floppy disk drive. They were the original "bookshelf" computer, long before today's Mini and Micro-ETX systems appeared.

I got a pair of system boards for these from Dave Baldwin when he was cleaning out some old computers prior to a move. One night, I really wanted to get one of the many systems up and running that Dave had given me, and since these seemed like they'd be the easiest to get running I grabbed one and got it going.

A complete computer, with Z-80 CPU at 4MHz, Floppy Disk Drive Controller, Serial and Parallel I/O, and SCSI all on one small card--in 1984!

Since then, I've been using it as a pretty maxed-out CP/M system. I put a 2GB SCSI hard disk on it, of which I'm only actually using 88MB (which is plenty, I never filled the 10MB of disk space on my old Kaypro 10 CP/M system, after all.) First, I played with it using just CP/M and its utilities. Since then, I've installed a couple of development systems--Turbo Pascal 3.02 and Workman's FTL Modula-2--as well as WordStar 3.0.

Honey, how about we eat dinner on the patio tonight?

I did move it off the dinner table! It's been living on an "occasional table" in our living room for the past several months (occasional tables seem to happen more than occasionally in our house.) I've been wanting to move it into my computer room in the house. But there wasn't room on my desk.

Then Vic Maris of StellarVue Telescopes offered me an old desk he didn't need at his offices any more. He said it was large. It is. I had to do some major work to get it into my office. But once there, I put my usual computers on it (an iMac 20" and a Beige G3 PowerPC Mac), and had enough room for one more computer!

My new desk, with Three full size computers.

I put the Ampro's current box (a PC's beige box) under the desk. I've got another enclosure for it that'll be much more attractive and interesting--but that's another project yet to come. On top, I had plenty of room for my ADDS 2020 terminal, which is the user interface for the Ampro. Unlike the original Big Board computer (the "Ferguson"), the Ampro uses a terminal, whereas the Big Board has a built in CRT and keyboard interface.

Once I got everything in place, I started working with my ADDS terminal to try to get the best image out of it. I originally used this terminal with the Ampro because it's the smallest full terminal I've got. I took a look at all the space on my new desk, and realized...I could use a better terminal. So I pulled out my VT-102, which has a very nice white on black character display and is very sharp.

The Beige G3 runs Lemmings and Warcraft, the iMac is my interwebs machine, it's desktop background is an image of the Big Board computer PCB, and to the right is my Ampro's terminal, here showing the utilities menu.

The VT-102 wasn't perfect, though. So, thanks to some help from fellow retrocomputerists I was able to find the technical info I needed to adjust the character height on the display (it was a little taller in one part than another when it came out of the garage.) Now it's perfect.

Now I'm happily writing games in Turbo Pascal at my desk, and the space next to my easy chair is waiting for another project to move in while my wife's back is turned.

Getting the new desk in meant moving some stuff out.

Here is my electronic workbench, covered in clutter. You can see my breadboard 8085 on the left, the new 8085 on the bench, with the face panel parts on top of the oscilloscope. The computer system is a 486 that I still use for burning ROMs and transferring data between newer systems and older ones. In front on the desk is the plastic tub that holds the Membership Card's parts. Doesn't everyone have a beef jerky jar filled with capacitors on their desk? Mine is on the right, with the blue and red things in it that aren't candy. On top of and beside the monitor are my three STK-500 development boards for my AVR projects. I have three so that I can have each set up for a different chip at the same time.

Since this picture was taken I've cleaned up. Really.

The breadboard version of my 8085 computer, the MAG-85 is still in use, by the way. That's where I've been doing my OS development while I finish the permanent version of the hardware. That way I don't have to worry if I've got the permanent one's keyboard and display off for work on the face panel if I want to sit down and code some 8080/8085 assembly.

Another Semester with Greenfoot

2010-06-18T13:38:00.000-07:00

Greenfoot continues to be a productive tool for my high school computer classes. This year we had two students with a strong programming background in the class. This turned out to be both good and bad for the teams. In both cases, the experienced programmers tended to dominate the teams and their work. They became a bottleneck in both teams to one degree or another.

I spent more time in class on project management than I have in prior classes to help deal with this. It worked well, but it didn't relieve all the problems the teams had.

In my classes, I do as much as I can to allow the students to organize themselves and run their own projects. At the high school level, I feel the students are ready for more autonomy as well as the opportunity to struggle with their assignments. I still put up some "guard rails", but as much as possible I let them run their own project teams.

Each team had a unique set of problems to overcome. In both cases, they managed to produce a playable game in spite of the problems. I managed to get every student to spend some time hands-on with their project's code and gain confidence in their ability to code on their own. And in spite of the groups' problems, both teams managed to stick to the class schedule. I build in a small amount of slop time at the end of the project schedule, but for the first time since I've taught this class, the teams had complete working code at the end of the scheduled time.

The high school team projects for the semester are online. We had two development teams:
"Bubbles" was developed by Ryan, Keeghan, and Coleton.
Team blog at: http://anysomething.com/blog/
Finished game is online at: http://www.greenfootgallery.org/scenarios/1416

"Qake" was developed by Eva, Caroline, Ian, and Jeremiah
Team blog is at: http://qakedevelopment.blogspot.com/
Finished game is online at: http://greenfootgallery.org/scenarios/1417

These links are also available on the class web page at: http://acedev.com/education/hscomp.html

HFE: Sacramento Area Electronics Parts Source

2010-03-31T21:53:00.001-07:00

There's a neat little place in Sacramento--next door to North Highlands--that sells lots of electronics supplies and surplus stuff, as well as some consignments. It's called HFE Electronics. It's at the prior location of HSC (Halted Specialties Corp., better known as HSC Electronic Supply.) HSC decided to consolidate, pulling out of the Sacramento location after over 25 years and focusing their attention on their Bay Area store and online sales.

HFE fills the gap that would have been left with the loss of HSC in this area. Not only that, but they've picked up for the Popkey Electronics store that recently closed here. They bought out Popkey's stock and are integrating it into their inventory now.

HFE is a fun place to poke around, ask questions of the staff (or, in my case, I more often get involved in helping the staff answer questions from other customers) and otherwise pick up all sorts of fun bits of electronics. They have everything from discrete components to ICs to equipment. There's new retail stuff as well as heaps of surplus and used stuff. There's lots of bits and bobs for those of us who like playing with microcontrollers, those of us who like building up analog circuits from scratch, amateur radio people, digital electronics types, tinkerers with pre-existing equipment, repairers of the $100 item with a broken ten cent part, and so on. Count me in all the above categories. I seldom get out the door without being about $100 lighter. :)

Among the things I noticed my last time in (no guarantees this will all be there when you walk in, especially if I beat you there) are:

An Odyssey 2 game console from the 70s (based on the 8048 CPU, with lots of room inside the case for mods!

Some Tek scopes and modules

An old Mac SE/30 unit (sans keyboard and mouse.)

Lots of interesting rocker switches

A bunch of LCD displays with 44780 controllers and similar

Oodles of LEDs and displays (I've picked up a bunch of dual digit 14 segment displays, among others.)

Prototyping boards, tools, wire jumpers for solderless breadboards, and other proto stuff.

Interconnects and sockets of all sorts of varieties.

This barely scratches the surface, and while some things are one-offs (like the Mac and Odyssey 2), much else is regular stock stuff. So if you're ticked about the fact that "Chicken Shack" doesn't have your favorite digital latch any more, take a stop by HFE Electronics.

8085 Project Schematic Posted

2010-03-29T16:52:00.000-07:00

I've posted a schematic for my 8085 based single board computer, the MAG-85, on my web site. The schematic covers the entire main board, previously I had only posted schematics of parts of the system in the assembly instructions.

Click the image to go there. The schematic is linked under "References" at the bottom of the page.

I'm presently completing the parts of the schematic that cover the front panel components as well as the bill of materials. This will all be posted as a PDF once it is complete.

In hardware, I have finished the keyboard and am assembling the front panel and the enclosure. This is all turning out very nicely, I'll be posting pictures soon. I'm especially happy with how the keyboard turned out. It looks really spiffy, even though it was created using very low-tech methods (I'm working to keep the whole project at a garage and desktop tech level for construction.)

8085 Microprocessor Project: MAG-85

2010-03-18T23:10:00.000-07:00

Here's a picture of the completed hand-wired circuit board for the MAG-85 (Micro Applications Gadget) 8085-based microcomputer system:

More info on this project at saundby.com.

I'm presently working on both a permanent front panel/enclosure and the permanent software. I'll be writing a machine language monitor program that will provide a number of utility routines for using the system's I/O.

The system has a 4x5 keypad,and an LCD display (16x2 is used here, I'll write the software to allow any two-line display from 16x2 to 40x2.) It also has 16 extra digital inputs and outputs. In the image eight of each are in use to read the state of a bank of DIP switches and display that on the 8 LEDs. The system can be expanded off-board with up to an additional 40 additional I/Os with the present I/O decoders.

The 8085's interrupt inputs are available as well, above I have switches on TRAP (the 8085's non-maskable interrupt) and RST7.5. RST6.5 is used by the keyboard, and RST5.5 will also be available on the front panel as a user program vector switch.

Everything's coming together nicely on this project now. I have detailed instructions on constructing the circuit on the project web page, with detailed instructions for a hand-wired board like the one above soon to come.

HP-35s Calculator Review: an Engineer's Look

2010-02-17T11:16:00.000-08:00

I've picked up an HP-35s calculator, see my full review.

The design hearkens back to HP's classic calculators for which it is still well known, such as the HP-41C, HP-65 and 67, and to a lesser degree, the HP-35. Unlike the original HP-35, the 35s is programmable and has lots of memory. It's more like an HP-67 or HP-41CV in many ways, which has spawned some unfair (to my mind) criticism.

I like the HP-35s a lot, you can find out why, and what I think could stand improvement here.