Robot 5: "MushroomBot"
This robot is a quick, simple, two-wheel design incorporating the case of an old centrifuge. The staff at the veterinary hospital where I work, (who generously let me salvage from their discarded equipment) were disposing of this faulty laboratory centrifuge. They told me it continually destroyed test tubes full of blood and other bodily fluids, splattering them all over the inside of the case. Needless to say, I had an interesting experience trying to clean it out--ever wonder what chunks of broken glass can do when they tumble around the inside of a dome-shaped plastic case at over 300 miles per hour? On the bright side, the outside of the case looks fine, and I salvaged a motor, a high-resolution speed control circuit, a handful of useful hardware, and some funky timing device with a metal bell (like the old fashioned wind-up alarm clocks, but with a switch attached to the bell). Anyway, the case is really all I was after, and the vet-techs just wanted to see this worthless piece of junk do something more entertaining than redecorating itself with goo!
There's nothing unique about this robot's design. It's the common theme of two drive wheels, a caster or two, and a handful of sensors. The centrifuge case is mushroom-shaped and round (which conveniently avoids getting caught on corners and such), and a lid on top for easy access to the inside.