What mechanical device did Leonardo da Vinci design to make a drum play by itself?

Leonardo da Vinci designed a self-playing drum operated by a rotating mechanism.

The device used a wheeled cart and a rotating drum fitted with pegs. As the drum turned, the pegs struck a drum surface and produced a repeating rhythm. The design is commonly interpreted as a musical automaton that could move and play without a human drummer.

Leonardo’s notebooks contain many studies of automated movement, including mechanical animals, stage effects, and military machines. The drum demonstrates how he combined cams, gears, and programmed contact to create a sequence of actions.

It is sometimes confused with Leonardo’s robotic knight. The knight was a human-shaped mechanical figure intended to perform movements, while the self-playing drum was a mobile musical device. Neither should be described as an electronic robot: both relied on Renaissance mechanical power and carefully arranged moving parts.