Leonardo da Vinci designed an odometer to measure distance by counting wheel rotations.
His cart-like device used a wheel that turned as the machine moved. A system of gears transferred the wheel’s motion to a counting mechanism, allowing the operator to estimate how far the cart had traveled. The design was useful for surveying and mapping, where consistent distance measurements were important.
Leonardo’s odometer was not the first idea for measuring travel distance; ancient engineers had developed related devices. Its significance lies in Leonardo’s detailed mechanical treatment of the problem and his attempt to make the result readable through a geared counter.
An odometer measures distance, while a speedometer measures speed. Leonardo also studied surveying instruments and mapping methods, but those devices should not be treated as interchangeable with this wheel-based distance recorder.