Leonardo da Vinci designed an odometer to measure distance traveled.
Leonardo’s odometer used a wheel that rotated as a cart moved. A gear mechanism transferred the wheel’s motion to a counting system, allowing the device to record the distance covered. The concept belongs to a long history of measuring travel by counting wheel rotations.
The design appeared in Leonardo’s notebooks among studies of machines, surveying, and military engineering. Accurate distance measurement was valuable for mapping roads, planning construction, and estimating the movement of armies.
An odometer is not the same as a compass, which indicates direction, or an odometer-like modern vehicle display that uses electronic sensors. Leonardo’s proposal was mechanical and depended on calibrated wheel movement. The exact accuracy would have depended on wheel size, gearing, and the surface over which the cart traveled.