That was my first attempt to build an uC-powered autonomous mobile platform. Or just robot, so to speak. Not too smart, not too sophisticated and not too much documentation was left after I built it, but he made me sink into wonderful land of robotics and electronics.
Building took me about 3 evenings and first thing I have learnt was using motors without any moto-reductors is not the wisest idea. I took two servomotors from HiTec (HS-322HD), Atmel Attiny 2313 micro and L293DNE H-bridge. The only two sensors were tact-switches with long, curved wires – aka tentacles.
You can read more here.