Leonardo da Vinci’s machine for recording the distance traveled was an odometer.
Leonardo designed a mechanical odometer in which a wheel’s rotation drove a counting mechanism. As the wheel moved along the ground, its turns could be converted into a measured distance, allowing surveyors or engineers to estimate the length of a route.
His design belongs to a long history of distance-measuring devices. Odometers had ancient precedents, but Leonardo’s notebooks show how Renaissance engineers studied gears, wheel sizes, and mechanical counting systems to make measurement more systematic.
The device should not be confused with Leonardo’s wind-measuring plate or humidity indicator. Those instruments measured atmospheric conditions, while an odometer measured travel distance through wheel movement.