Leonardo da Vinci designed an odometer to measure distance by counting the rotations of a wheel.
His odometer concept used a large wheel that turned as it moved along the ground. A gear mechanism transferred the wheel’s motion to a counting system, allowing the operator to estimate how far a cart or surveying device had travelled.
The design is associated with Leonardo’s studies of mechanics and surveying. Measuring distance accurately was valuable for mapping, road construction, military planning, and civil engineering. Leonardo’s version belongs to a long history of wheel-based measuring instruments rather than being the first odometer ever conceived.
An odometer is not a speedometer: an odometer records total distance, while a speedometer measures rate of travel. Leonardo’s design also differs from modern electronic vehicle odometers, which use sensors and digital displays. His mechanism relied on visible mechanical motion and geared counting.