To beat a friend who keeps winning at badminton, Jack Saito built a motorized racket that spins rapidly to hit shuttlecocks. A single racket vibrated too violently, so he mounted a second one on the opposite side to balance the mechanism. Powered by an electric-skateboard motor and batteries carried in a backpack, it returned shots on court, but ran out of power before he could win.

A spinning top eventually slows down, so this project answers by putting a brushless motor, ESC, microcontroller, rechargeable battery and eccentric weight inside the top and keeping it going for roughly two hours. It works without an external base or magnets.

When the spin weakens, the internal mass shifts the center of gravity and adds energy back into the motion. Electronics and mechanical control are deployed directly against the very normal fact that tops stop spinning.