Leonardo da Vinci designed an odometer that used a rotating wheel to measure travel distance. As the wheel turned, a linked mechanism counted rotations and transferred markers into a container, allowing distance to be estimated.
His design was connected with surveying and mapmaking. A known wheel circumference could be multiplied by the number of rotations, creating a practical way to measure roads or distances across land. The mechanism illustrates Leonardo’s interest in converting continuous motion into counted units.
An odometer measures distance traveled, whereas a speedometer measures speed and a pedometer counts a person’s steps. Leonardo’s wheel-based concept was not an automobile instrument in the modern sense; it was a portable measuring device for journeys and surveying.
The basic principle remains familiar today. Modern vehicle odometers use gearing and electronic sensors, but they still translate wheel movement into accumulated distance. Leonardo’s design is notable as an early mechanical version of that same general idea.