The Machine

The explanation

The machine is set off by an elastic snapping to set up a chain reaction of dominos, (elastic -> mechanical)

the chain of dominos is set to push a ball which then falls off a ledge down to a semi circle, (mechanical -> gravitational)

the ball goes through the semi circle directly down to a ramp, (gravitation -> mechanical)

the ball goes down the ramp directly on top of the alarm clock button, contained in a small box, which turns off the device. (mechanical -> gravitational)