Leonardo da Vinci designed an odometer that recorded distance by dropping pebbles from a rotating wheel.
Leonardo’s cart-based odometer used a wheel whose rotation was linked to a counting mechanism. As the cart traveled, the wheel turned, and the mechanism released one pebble into a container after a set distance. Counting the collected pebbles gave an estimate of how far the cart had moved.
An odometer measures distance traveled. Leonardo’s design did not display mileage in the dashboard style familiar today, but it applied the same fundamental principle: wheel rotation can be converted into a distance measurement.
The device is sometimes mistaken for a speedometer, which measures speed rather than total distance. It also differs from a surveying instrument used to determine angles or elevations. Leonardo’s odometer shows his interest in turning physical motion into numerical records.