Leonardo da Vinci designed an odometer to measure distance traveled.
His mechanical design counted wheel rotations as a cart moved. A wheel of known circumference could convert those rotations into a distance, while a linked mechanism recorded the result. The concept is closely related to the odometers later used in vehicles and surveying equipment.
Leonardo’s device was not a speedometer, because it measured accumulated distance rather than speed. It was also not a compass: navigation instruments determine direction, while an odometer tracks movement along a route.
The design shows Leonardo combining geometry, wheels, gears, and counting mechanisms. Similar measuring carts were useful for surveying roads, mapping land, and estimating travel distances.