Leonardo da Vinci designed an odometer to measure the distance travelled by a cart.
His mechanical odometer used a wheel that turned as the cart moved. Gears connected the wheel’s rotation to counting mechanisms, allowing the machine to register distance in regular increments. The design was useful for surveying, mapping, and measuring roads.
Leonardo’s version belongs to a much older family of distance-measuring devices. Ancient Greek engineers, including Vitruvius’s tradition, described cart odometers that counted wheel rotations. Leonardo’s importance lies in his detailed Renaissance treatment of the mechanism and its practical integration with gearing.
An odometer measures accumulated distance, not instantaneous speed. That distinction separates it from a speedometer. The device also differs from a pedometer, which counts a person’s steps rather than the revolutions of a vehicle wheel.