Leonardo da Vinci’s odometer was a cart designed to measure distance with a rotating wheel.
Leonardo’s odometer concept used a wheel that turned as the cart moved. Gears transferred the wheel’s rotation to a display mechanism, which could release a small object after a set distance. In the best-known design, a container dropped stones into a box, allowing the number of intervals traveled to be counted.
The device was useful for surveying and mapping, especially when measuring roads or land over uneven ground. It did not directly display distance in the digital sense; its reading depended on the wheel’s circumference and the calibrated gearing.
Leonardo did not invent the basic idea of measuring travel by wheel. Ancient Greek engineers had developed related devices, including mechanisms associated with Heron of Alexandria. Leonardo’s importance lies in his detailed Renaissance design and his effort to connect wheel rotation with a countable record.