This week I soldered up the "secondary board" to my OOPic2 so I can attach the 40pin IDE connector to it without soldering my OOPic board. From the secondary board, I have 8 outputs (enable,fwd,rev, and PWM-speed for left and right) and 7 inputs (5 contact switches, 1 IR module, and 1 A2D for battery monitoring). BTW, solder flux RULES!
Since the switches are bolted to the outer shell of the bot, the connections are made to an IDC header, that I can connect the switches to. That way I can remove the shell without having permanent wires attached. Using the internal pullup resistors on the OOPIC is going to make the switch circuits really simple and clean.
I got a couple emails about the wheels and gear motors. I bought the motors from www.sciplus.com about 8 months ago. They were from one of the battery operated kiddy cars. The output shaft was unique in that it was 2.25" in diameter and was divided into 10 sections. I was originally going to just replace the shaft completly, but as luck would have it, by breaking off every other section, it fit exactly into my lawn mower wheels. (shell1.jpg shows the wheel). This was an astounding bit of luck that it matched size, radius, and depth! After that, I bought two more motors as spares!