Leonardo da Vinci designed an odometer that recorded distance by counting wheel rotations.
His cart-like device used a wheel linked to a gear mechanism. As the wheel turned, the gears transferred motion to a container that released a small object at regular intervals. Counting the released objects allowed the operator to estimate the distance traveled.
The design is associated with Leonardo’s studies of surveying, engineering, and military planning. It did not directly display distance in the modern numerical form seen on a vehicle dashboard, but it converted movement into a measurable record.
An odometer is not the same as a speedometer. An odometer measures accumulated distance, whereas a speedometer indicates current speed. Leonardo’s device also differs from the ancient wheel odometer traditionally associated with engineers such as Vitruvius and Heron, because similar distance-measuring mechanisms existed long before the Renaissance.