The robot is built around an old, 99 cent hand-held fan I got at Ace Hardware. It uses two AAs and avoids obstacles. Originally I was going to glue a convex lens or attach a piece of Teflon to the bottom of it so it could skid. My first idea resulted in no motion, well... except for the robot tipping over. After a trip to Ace (again), I had an axle made out of a thin dowel and two wheels (washers). Unfortunately, the wheels tipped so much they were unusable. A small piece of dowel glued on the end of the axle created a barrier that solved that problem. When I tried it out on a smooth surface it remained motionless (but it didn't fall down!). I tried covering the bottom with foil and even sprayed some WD-40 on it to make the bottom slick. Nothing. The solution was to put a blob of glue on one blade to create an eccentric weight to make the robot move by vibration. After I added a round bumper to make it move around obstacles it was fine. Cost: Fan-- 99 cents Wheels-- 60 cents Axle-- 4 cents Bumper-- Scrap from windsheild wipers Glue Blob-- 2 cents Pipe cleaner(to keep bumper bent)-- Scrap Glue to keep it together-- Scrap Total Cost-- $1.65 FYI: This is 10 cents less than Mark Tilden's "Walkman," the cheapest robot in the world. (Though Mr. FM has nowhere near the capabilities of Walkman, and I don't really consider FM a robot) Sorry aout the length of this description! Email: cjmartin@xnet.com