Leonardo da Vinci designed an odometer mechanism to measure the distance traveled by a cart.
His device used a wheel that turned as the cart moved. A geared system transferred the wheel’s rotation to a display, allowing the mechanism to count completed revolutions and convert them into distance. The design was intended for surveying and mapmaking.
Leonardo’s odometer was not an electronic instrument and did not measure speed. It belonged to a long tradition of mechanical distance counters, including ancient devices associated with road measurement.
The key distinction is between distance and direction. An odometer records how far a vehicle travels, while a compass indicates orientation and a speedometer measures rate of travel. Leonardo explored all kinds of measurement machinery, but this invention specifically addressed traveled distance.