What Leonardo da Vinci invention used a wound spring to power an unmanned cart?

Leonardo da Vinci’s self-propelled cart used wound springs to move without an animal or person pulling it.

He designed the cart around 1478–1480, making it one of the earliest known concepts for a programmable, self-moving vehicle. Two symmetrical leaf springs stored energy, while a system of gears transferred that energy to the wheels. Adjustable pegs could control the cart’s route, allowing it to follow a predetermined path.

The machine was probably intended for theatrical effects or court entertainments rather than transportation. It was not an automobile in the modern sense: it had no internal-combustion engine, steering wheel, or passenger cabin. A full-scale reconstruction was built for a 2006 exhibition at the Museo Galileo in Florence, demonstrating that the mechanism could move when assembled according to Leonardo’s surviving drawings.