Leonardo da Vinci designed an odometer to record the distance traveled by a vehicle.
His mechanical device was linked to a cart’s wheels. As the wheels turned, a system of gears moved a container or counting mechanism by regular increments. In one well-known reconstruction, the mechanism released a small object at set intervals, allowing the traveled distance to be calculated from the number collected.
An odometer measures distance, while a speedometer measures speed and a compass indicates direction. Leonardo’s design was not an electronic instrument and did not resemble the digital displays found in modern cars. It was an ingenious mechanical solution based on wheel rotation and gear ratios.
The sketch demonstrates Leonardo’s habit of converting movement into measurable data. Similar principles remain in use today: modern vehicle odometers still determine distance from wheel or drivetrain rotation, although sensors and electronics have replaced most exposed mechanical gearing.