Leonardo da Vinci designed an odometer mechanism for measuring distance traveled.
His odometer concept used a wheel that turned as a vehicle moved. A system of gears transferred the wheel’s rotation to a counting mechanism, allowing the device to register the distance covered. The idea appears among Leonardo’s engineering studies and reflects his interest in converting motion into measurable information.
An odometer is not a navigation compass. A compass indicates direction, while an odometer measures travel distance. Leonardo also studied surveying, mapping, gears, and other instruments that could help engineers and military planners record physical measurements.
Modern odometers are commonly built into vehicles and use electronic sensors, although mechanical versions once relied on rotating wheels and numbered drums. Leonardo’s proposal belongs to the mechanical tradition that preceded those modern instruments.