Here's something I was thinking about... an 8051-based autonomous vehicle. One of those toys that just run around until they bump into something, then change direction and run around some more.

I was thinking of making a cheap one using those small 3V DC motors and controlling them with PWM. You'll need 2 motors for rudimentary direction control (one for each side, you change direction by changing the speed of each motor). Alternately you could have a motor for drive and one for steering but that seems improbable with a simple DC motor. But with the timers on 8051, you could easily implement independent PWM drive for both motors.

Once you have one running around you could introduce a motion encoder for position feedback. For this I was thinking of using an old dis-used computer mouse. There's a good webpage on the boondog.com site that explains how you can hack a simple mouse to get a perfectly good rotary encoder. This can also be used for collision detection (i.e. you are firing motor drive signals but getting no significant motion signals from the encoder)

Once you have a functional toy like this, you can build more complex methods on top of the basic navigation functionality. Give it a task, maybe like navigating a maze or something. Now THAT would be a fantastic project.

Kundi