Leonardo da Vinci designed an odometer to measure the distance traveled by a vehicle.
His concept used a wheel that turned as the vehicle moved, transferring motion through gears to a counting mechanism. The arrangement could record the number of wheel rotations and convert that total into a distance. Leonardo's drawing is one of the best-known Renaissance examples of a mechanical distance-measuring device.
The design belongs to his broader studies of gears, motion, and surveying. An odometer measures accumulated distance, not instantaneous speed or direction. That distinction separates it from a speedometer and a compass, two instruments sometimes confused with it in general descriptions of vehicle equipment.
Distance-measuring wheels existed before Leonardo, including ancient examples associated with Hellenistic engineering. Leonardo's contribution was to analyze and depict a compact mechanical arrangement suited to Renaissance vehicles and engineering work.