Leonardo da Vinci sketched an odometer to measure how far a cart traveled.
His design linked the motion of a cart wheel to a counting mechanism. As the wheel turned, a system of gears transferred movement to a display or container, allowing the device to record distance. The idea belongs to Leonardo’s broader interest in turning continuous motion into measurable information.
Leonardo’s odometer is commonly described as a wheel-based distance recorder. Some reconstructions use a small wheel that releases a pebble into a box at regular intervals, while gears help count the wheel’s rotations. The exact details vary because the surviving drawings are designs rather than a documented mass-produced instrument.
It was not a modern electronic mileage counter. Nevertheless, the principle is the same: determine distance from wheel rotation and a known circumference. The word “odometer” comes from Greek roots meaning path and measure.