Leonardo da Vinci’s cart used an odometer to record distance traveled.
Leonardo designed a wheel-based measuring device in which the rotation of a wheel drove a counting mechanism. As the wheel turned, the mechanism could register units of distance, creating a mechanical record of how far a vehicle had traveled.
This type of instrument is called an odometer. The word refers specifically to distance measurement, so it differs from an altimeter, which measures height, and a speedometer, which measures speed. Leonardo’s design belongs to the long history of mechanical counters used in surveying, engineering, and transport.
The device was part of Leonardo’s broader interest in converting motion into useful information. His notebooks contain many studies of gears, wheels, and linked mechanisms, although not every sketch was turned into a working instrument.