1) Got rid of the AAA battery pack and added twin 2200 mah nicad rc packs wired in series. These are slung along the bottom and just visible in the photo.
2) Added more decks. I cut the decks from 1/16" aluminum stock with a jigsaw. I used the original deck as a template. Hex standoffs are used to support the decks.
3) Upgraded the BS-2 to the much more capable BX-24. This controller features much more memory, speed, does multitasking and A/D conversion.
4) Added an array of 5 sharp GDP02 IR sensors along the front. The board on the middle deck contains a PIC 16F84 based coprocessor I built that handles fetching readings from the GDP02 and reporting back to the main processor.
5) An XCAM2 and battery pack sit on the top deck. The camera and receiver can be had for $79.00 for the set from http://www.x10.com. They also give you a $40 gift certificate for your next purchase. The camera also picks up audio. While the picture quality is generally poor, it is still usable, and the price can't be beaten. The receiver is hooked to a Haupage video capture card on a Win 98 box. Range is pretty much adequate for around the house and not excessively directional. Motor noise does not appear to be a big problem.
More sensors. Additional Sharp units will be added to the other decks and the rear. Ultrasonics will also be added.
I've also purchased a couple of radio tranceivers to allow remote control from a PC, although these are not yet installed. I will also be adding an IR remote receiver for manual control -- I may steal this board from another robot I've built.