A BristleBot is a device that uses vibrations to move. The vibrations are created by a mini-offset motor, the same type of motor that makes cell phones vibrate. If you look closely at the motor, you’ll see an uncentered weight attached to the axle. As the motor spins, the inertia of the spinning weight pulls the motor in different directions, causing it to vibrate. Because the motor is strapped to the brush, the vibrations are transferred to the brush, making it move.