Leonardo da Vinci designed an odometer that recorded distance traveled using wheels and a counting mechanism.
His device was intended for surveying and mapmaking. A wheel rolled along the ground, and a linked mechanism transferred its movement to a series of counting wheels. The count could represent how far the wheel, and therefore the machine carrying it, had traveled.
Leonardo’s odometer was not an electronic instrument and did not display distance in the modern automotive sense. Its value came from converting continuous rolling motion into a numerical record. That principle remains central to mechanical odometers, even though modern vehicles generally use electronic sensors.
An odometer differs from a pedometer, which counts a person’s steps, and from a speedometer, which indicates speed. Leonardo worked on many surveying and engineering ideas, so his odometer is part of a broader effort to make measurements more systematic and repeatable.