Da Vinci's unusual sleep pattern (3.5 hours awake, followed by 30 minues asleep) may have pushed him to develop an alarm clock. His design was based on a water clock, and included set amounts of water that were dropped into a resevoir, which when full would activate several levers that propped his legs up, and woke him.

His plans and sketches for this devide were found in his Codex Madrid.