Leonardo da Vinci sketched an odometer to record how far a cart traveled.
His design used a cart wheel connected to a counting mechanism. As the wheel turned, the mechanism was intended to release a small object at regular intervals into a container. Counting the released objects would indicate the distance covered, provided the wheel’s circumference and the interval were known.
Leonardo’s odometer belongs to a long history of distance-measuring devices rather than being the first odometer ever conceived. Ancient engineers, including Vitruvius, described related wheel-based systems. Leonardo’s importance lies in the clarity and practicality of his Renaissance design. An odometer measures distance, whereas a speedometer measures speed; the two instruments are commonly mixed up because modern vehicles display them together.