What Leonardo da Vinci device used falling weights to make a clock strike?

Leonardo da Vinci designed an alarm clock that used falling weights to make a clock strike.

His clock design separated the measurement of time from the mechanism that produced an alert. As the timekeeping process advanced, a weight could be released or moved so that it triggered a hammer. The hammer then struck a bell, giving the sleeper an audible signal.

The design is usually discussed as an early mechanical alarm concept rather than as a mass-produced clock. Leonardo's notebooks contain many studies of gears, escapements, springs, and repeated motion, showing how closely timekeeping was connected to his broader mechanical investigations.

This device should not be confused with an hourglass or water clock, which measure time through sand or water flow. Leonardo's design belongs to the family of mechanical clocks that use gears and stored or falling energy to create motion.