Leonardo da Vinci designed an odometer to record how far a cart traveled.
His design connected a cart wheel to a counting mechanism. As the wheel turned, gears transferred motion to a series of numbered wheels, allowing the device to register distance. The concept is usually described as a cart-mounted odometer rather than a handheld instrument.
Leonardo was not the first person to imagine measuring travel distance. Ancient Greek and Roman engineers had already developed related devices, but his Renaissance design is notable for its clear mechanical arrangement and practical use. Modern odometers still rely on the same basic principle: counting wheel rotations and converting them into distance.
A common mix-up is confusing an odometer with a speedometer. An odometer measures accumulated distance, while a speedometer measures current speed.