Leonardo da Vinci designed an odometer that used a wheel and gears to record distance traveled.
His concept connected a measuring wheel to a gear train. As the wheel turned while moving across the ground, the mechanism advanced a counting device. This allowed distance to be recorded mechanically rather than estimated by eye.
Leonardo’s odometer belonged to a broader Renaissance interest in surveying, mapping, and military logistics. Accurate distance measurements could help engineers plan roads, fortifications, canals, and other large projects. The design also shows how he applied gear ratios to convert continuous motion into discrete counts.
The device was not a modern electronic odometer, and the surviving drawings do not establish that Leonardo built a working version. It is best understood as a mechanical measuring design.