A couple days after I bought theBasic Stamp, my Atmel kit arrived, pretty much destroying any hopes for the poor Stamp to be a part of this project.
I set up the STK500 and the pre-programmed AT90S8515 started pulsing an LED on the board. Then I installed the AVR gcc toolchain on my PowerBook, and a couple of hiccups later (you have to explicitly erase it before programming), I was writing C code and watching LEDs blink. The AVR gcc toolchain worked very well on Mac OS X, but I did have to make a minor change to one of the include files to get it to compile for the ATmega32. Targetting the AT90S8515 that came with the STK500 worked without modification.

I’ve started building a new main board around the ATmega32 controller. I cleaned up the layout and added some LEDs to give status info. In the picture below you can see the PIC16F877-based board on the left, and the new board on the right. The new parts placement should allow marginally better cooling (the fins of the MMC heatsink are now aligned with the primary direction of the airflow when the bot is in motion). I also superglued most of the components down before wiring, which helps keep them in place as I work on it.

PIC16F877 Board and ATmega32 Board

The board on the left is still populated with the PIC, Solutions3 Motor Mind C module and Analog Devices linear accelerometer.
The board on the right is a little farther along than is shown in the image. I've wired the LCD header (in the lower-right) as a first step, but I'm having trouble getting the AVR to actually output onto PORTC what I've specified in the code.
Since Capilano finally came out with a Mac OS X version of DesignWorks, I’ll probably get a real board designed and fabbed in the next couple of weeks. I have a couple of ATmega128 parts which have, among other things, two USARTs, and a couple more I/O ports. Since one USART is used for communicating with the MMC, it’ll be nice to have the other one for relaying data back to a host computer for analysis.
Now, it’s time to do homework. I’ll try to write more soon.