Leonardo da Vinci designed an odometer, a device for recording how far a wheeled vehicle traveled.
Leonardo’s wheel odometer used a wheel that rotated as the vehicle moved. A geared mechanism counted the wheel’s revolutions and released a marker or other indicator at regular intervals. By relating the number of rotations to the wheel’s circumference, an observer could estimate the distance covered.
The principle is straightforward but important: a known wheel size converts rotation into distance. Leonardo’s design was intended for practical surveying and engineering, where measuring roads, routes, and building sites accurately could save time.
An odometer measures distance traveled, whereas an anemometer measures wind speed and a speedometer measures current speed. Leonardo’s device was mechanical and did not depend on electronics, satellites, or a modern vehicle engine. Odometers existed in earlier forms, so Leonardo should be credited with developing and illustrating a Renaissance version rather than inventing the general idea of distance measurement.