Leonardo da Vinci designed an odometer, a wheeled device intended to measure distance traveled.
His design attached a counting mechanism to a cart wheel. As the wheel turned, gears transferred its movement to a series of numbered wheels. Each completed wheel rotation represented a known distance, so the device could record how far the cart had traveled.
The underlying idea was much older than Leonardo: ancient engineers used distance-measuring devices for roads and surveying. Leonardo’s importance lies in the clarity and mechanical sophistication of his Renaissance design, not in inventing the general concept from nothing.
An odometer measures distance, while a speedometer measures speed and a pedometer counts a person’s steps. Modern vehicle odometers use mechanical or electronic sensors, but they preserve the same basic principle of converting movement into a numerical reading.