This machine, known since antiquity, is for measuring distance traversed. Leonardo's odometer looks like a wheelbarrow provided with sprocket wheels. The vertical wheel takes a step with every turn of the hub of the wheel that rests on the ground. The vertical sprocket wheel has on the inside a peg which, at every full revolution, meshes with the horizontal wheel. The latter is provided with holes through which small metal balls or stones are collected into a dedicated holder. The distance traversed can be easily inferred by counting the balls/stones collected.
The model is based on the drawing:
- Codex Atlanticus f. 1b r. (1503)
Milano, Biblioteca Ambrosiana