Leonardo da Vinci designed an odometer to measure distance traveled by counting wheel revolutions.
His design linked a cart wheel to a counting mechanism. As the wheel turned, a series of gears moved small containers or indicators, allowing the user to estimate how far the cart had traveled. The principle is the same basic idea used by mechanical vehicle odometers.
Leonardo’s odometer was not an electronic instrument and did not resemble the digital displays found in modern cars. It was a mechanical surveying device, useful for mapping roads, planning engineering works, and measuring journeys.
The design is often associated with Leonardo’s broader interest in recording motion precisely. An odometer measures distance, while an anemometer measures wind speed and a hygrometer measures humidity; those are separate instruments in his notebooks.