Friday, October 31, 2008

Atmel STK-500 Starter Kit for AVR: Now with Death-bots

I've been programming the Atmel AVR microcontrollers for some time, I got started with the old AT90S1200 a long time ago, and I've been enjoying programming them ever since. Shortly after I started using them, new chips came out that I couldn't program with my Xeltek SuperPro/L programmer. So I picked up an STK-500 starter kit to use as a programmer and for light prototyping of AVR circuits.

My old STK-500 has gotten quite a workout. I've used it with a lot of different AVRs and built a bunch of other prototyping hardware around it. Unfortunately, I usually have more than one project going at a time and often I'd like to use the STK-500 for more than one. It's also a pain to change the configuration of the board to and from some chips, like the ATTiny26, one of my favorites.

When I ordered some of a new model of AVR the other day (ATTiny13A, a big upgrade from another of my favorites, the ATTiny12), I decided to pick up two more STK-500s (I wish I'd decided to get them back when they were only $50, but oh well.)

The STK-500 itself is pretty much the same, except that it's lost the serial memory IC that they had on-board (which I never use.) But the packaging has changed significantly:

STK-500, Now with spear-throwing cybernetic Odin kill-bot.

STK-500 boxes. Old on right, bigger new box on the left.

The old box is nice enough. It's got that "Wonders of Science" look to the art that reminds you of the stuff they tried to dress up at school to make it seem interesting when in fact it was a drab treatment of something that could have been interesting before the educational system sucked all the life out of it.

The new box is something else again. When I got it, I wondered if the increased size and the new art meant something. Like maybe a spear-throwing one-eyed Odin kill-bot inside? With cyborg Hugin and Munin?

Unfortunately, no. If I want an AVR-powered kill-bot I'll still have to build it myself. The increased size of the box just provides more room for the STK and its cables inside. The preprogrammed board demo still just uses switches to make an ATMega8515 flash LEDs. No Doom-Spears or all-seeing crows to report back to you what you've been missing in the neighbor's yard.

I was a little disappointed that they didn't throw in an extra IC this time. My first set included a sample ATMega163 as well as the AT90S8515 that ran the demo program. It also had a hardcopy parametric list of AVR devices that were available at the time. The set still includes a fairly current CD with software and family data on it, but no additional chip samples. A free ATMega644P would have been really nice. ;)

Still, I got the main thing I wanted. New STK-500s. Now I can work on three things at once without having one project wait on another to finish. And I've got cool pictures of a Norse microcontroller robo-dude. I think I'll take one into my classroom to hang up on the wall.

Edit: One thing the new STK500 comes with that the old one didn't is a handy little JTAG adapter. That's got more long term utility than a hardcopy user's guide, I guess, but I still miss getting the guide with its listing of the LED blinker demo program in the back.

Wednesday, October 22, 2008

New Bookshelves for the Computer Room

I went shopping for a couple of bookcases for my computer/electronics room this week. I wanted a pair of sturdy six foot tall shelves to replace some four foot stacks of cardboard boxes along one wall. I wanted to pay about $100 per shelf, but was prepared to pay up to $140 apiece for decent shelves. My requirements included a depth of no more than 14 inches if possible with a hard limit of 16 inches to avoid cutting into a walkway, sturdy construction and a reasonably professional appearance. If at all possible I wanted something on feet to allow vacuuming underneath and behind, and 2 or 3 drawers in the bottom would be awfully nice.

Sturdy is important to me. I'm a practiced abuser of bookcases, with more than a few exploded cases and collapsed shelves to my credit (so to speak.) I'm a packrat of data books, journals on glossy stock, and I top-stack and double stack when unsupervised. I try to fight the worst of these habits, if nothing else because they work against my using my books.

When I looked in at our local oak furniture store I found that seven-foot shelves of the sort I bought for our living room last year had jumped over $100 in price. The six footers that came closest to what I wanted were priced at $210 apiece. Even if the store had been willing to dicker, the shelves sat with the bottom shelf on the floor so they weren't really what I wanted even if we could get closer to my price.

I then stopped at our only other dedicated furniture store in the area. It's a nice, friendly discount place in a sort of quonset hut warehouse. Most of their stock is in living room furniture--over half the floorspace is covered with sofas--but they carry a few nice pieces of office furniture so figured I'd give them a look.

Unfortunately, all they had was either cases like those at the oak store (in a wider range of finishes), and large deep heavy pieces like display cabinets for living rooms. The prices on the straight bookcases were the same as at the oak store.

I walked out sarting to assemble a list of lumber, fasteners, and finishes to buy at the hardware store. I really didn't want to make my own, especially when I considered how much time it'd take away from other current work. But I sure wasn't going to pay double for something that wasn't even what I wanted.

More to kill time while I thought than with any expectation of finding something, I stopped in at our nearest Target store. I figured I could think through my budget again, and plan out where else I might go looking further afield. When I got to the furniture section I saw a couple of different shelves along the lines of what I was looking for. One was at the top end of my planned price range, the other on sale at my preferred price. Neither had drawers in the bottom, but otherwise they met my requirements and desires.

I ended up getting a pair of the cheaper ones. Six foot "honey" colored (sort of a maple finish) bookcases. Unlike the ones from the furniture stores they're assemble-yourself, but that's better than design-and-fabricate-yourself as far as time and effort is concerned.

They went together easily, about ninety minutes each. The stain job isn't perfect, but it's good enough for working furniture. Good enough that I didn't bother touching it up. There's a fixed shelf in the middle that adds a lot of strength and stability, I'd have a hard time exploding these. Also, the carcase--the structural parts of the case--is made of hardwood, not pressboard. This makes the case stronger, lighter, and more dimensionally stable.

The shelves are pressboard, but they're reinforced with hardwood to prevent warping and sagging.

Assembly was easy, even easier because I didnt follow the order given in the instructions. I installed the lintel ornament before putting on the top, and the top before the back panels. In both cases I had better light and access to the work than if I'd followed the given order.

The shelves also came with restraint cables to attach them to the wall. I didn't realize this. So I stopped at the hardware store and bought two kits on the way home from Target. Oh, well. I've got one other shelf at home that I'd like to change out the restraint on, then I'll take the other kit back.

The bookcases are in place and loaded up. They look great and they're proving to be as strong as I hoped. They'll also save me from worrying about cardboard box collapses this winter, and let me focus on my various electronic projects.