Another Junkbot, this time from a dead PS2 mouse. Knocked out in a couple hours from parts that were already on hand. Its main purpose in life is to entertain my son, he's been wanting a junkbot of his own for a while. Hopefully he learned something from the making of this one as well.
The brains consist of a pair of junkbox relays (probably from an old modem), a bumper switch from an old VCR, two LEDs, and a 2200uF 16V capacitor. When the bumper is hit the relays are triggered to reverse the motors, light the LEDs, and charge the capacitor. When the bumper is release the cap continues to energize the relays, but one relay is powered through the LEDs, so it un-reverses first, causing the 'bot to turn until the cap is completely discharged.
The drivetrain is two motors probably pirated out of old CDROMs, paired with servo degree wheels for wheels. Both wheels are wrapped in some smooshy medical tape for traction.
On R4's maiden voyage it crashed into a cabinet and launched one wheel across the kitchen and under the stove. I did attempt a video, but the 'bot had crashed before the camera had even started recording... All I got was 5 seconds of lousy, no-light video of R4 spinning in place with one wheel.
As I write this the new super glue to hold the wheel on the hub is drying. Later today I'll try getting more video.
Update Aug. 19, 2009
R4's second voyage resulted in the other wheel flying off. After another round of superglue R4 violently smashed its bumper switch into a wall and dislodged something causing the reverse circuit to no longer function. Before that was repaired it happened again, tearing the whole switch assembly off. I guess I need to come up with a more robust bumper switch.