By Jordan Gaither, updated March 24, 2022
Homemade robots are a fun, low‑cost way to explore mechanics, electronics, and the basics of robotics. With a toothbrush, a few household items, and a cell‑phone motor, you can assemble a vibrating robot in under fifteen minutes.
Using scissors, cut the bristled head of a new toothbrush, leaving about a third of the neck attached. This small stub will keep the motor centered.
Lay a strip of double‑sided tape flat across the top of the toothbrush head, resting on the bristles.
Attach the cell‑phone motor to the tape, with its shaft pointing away from the remaining neck. Ensure the motor head won’t touch the toothbrush when it spins before securing it.
Place one of the motor’s wires flat on the tape and press a 3‑V coin‑cell battery over it. Then bend the second wire so it touches the battery’s top, completing the circuit.
When the circuit closes, the motor spins and its unbalanced shaft vibrates the toothbrush, making the robot roll or ricochet across smooth surfaces.
If the robot tips over, trim the neck a bit more or reposition the components so they sit centered on the tape. The vibration comes from the motor’s unbalanced shaft.
