Leonardo da Vinci designed an odometer to record how far a traveling vehicle moved.
His design used a wheel that turned as the vehicle advanced. A mechanism transferred the wheel’s rotation to a counting system, allowing the device to register distance traveled. This made it useful for surveying, mapping, and measuring roads or military routes.
An odometer was not originally a modern automobile instrument. Earlier distance-measuring devices existed in antiquity, and Leonardo’s contribution was a Renaissance design that applied mechanical counting principles to travel measurement.
The device is sometimes confused with a speedometer. An odometer measures accumulated distance, while a speedometer measures speed at a particular moment. Leonardo’s design belongs to the first category and illustrates his interest in combining wheels, gears, and systematic observation.