In this video Turnvater Janosch demonstrates his homemade mechanical ball clock:
The clock runs for 12 hours, driven by a weight of 2.5 kg sinking approx. 1 meter during that time..Every minute a marble is lifted up and goes down a marble run with three flipping traps that count marbles for minutes, five-minute-steps and hours.
The timekeeping element is a second-pendulum with a pinwheel escapement.
Via Hacked Gadgets.