[Harm's] tumbling robot from a few years back is an excellent study in simple motion. Foregoing wheels or legs, he uses four flippers to roll the robot around the room. Two motors are used, each in charge of two flippers. Identical but separate circuits drive the motors with a 74HC240 gate IC monitoring the continuously rotation. When a flipper becomes stuck, the circuit reverses the rotation of the motor so the simple bot can tumble its way out of a jam.
The circuitry is less advanced than some of the BEAM builds we’ve seen before. That doesn’t diminish the cleverness of his design and we think BEAM robotics are great way to get your head out of the computer code and go hardware only. After the break you can take in some video of the tumbling motion. We’ve also included a video of another bot from his website that uses concentric rings for another type of unique locomotion.