Leonardo da Vinci sketched an odometer for recording the distance travelled by a vehicle.
Leonardo’s odometer design used a wheel that turned as a cart moved. A geared counting mechanism could register each revolution, allowing the machine to estimate the distance covered. The basic principle remains familiar in modern vehicles, although contemporary odometers use more precise mechanical or electronic systems.
The device was part of Leonardo’s interest in measuring motion and designing practical engineering instruments. By linking wheel rotation to a count, it transformed movement along the ground into a numerical record.
An odometer measures distance, not speed. A speedometer gives the rate of travel, while a compass indicates direction. Leonardo’s design is therefore best identified by its counting function: it recorded how far the vehicle had gone rather than how fast it was moving.