Leonardo da Vinci sketched an odometer to record the distance traveled by a vehicle.
An odometer measures traveled distance by linking wheel rotation to a counting mechanism. Leonardo’s design used a wheel and gears so that repeated rotations could be converted into a numerical indication of distance. The concept reflects his broader interest in mechanical measurement and accurate surveying.
Leonardo’s odometer was not an electronic instrument. It belonged to the mechanical tradition of distance counters, in which a known wheel circumference provides the basis for calculation. If the wheel turns without slipping, each complete revolution corresponds to a predictable length of travel.
An odometer is different from an odograph, a related device intended to record a route or trace movement. It is also different from a speedometer, which measures speed rather than total distance. Leonardo’s design is therefore best identified specifically as an odometer.