(continued at Debouncing in reality)

The clock needs buttons to set the time / inject clock pulses for the different counters. Just use push buttons then. But they have naughty bounces...

My past attempts at making a debouncing circuit failed. But I just looked at David Johnson on-off circuit (discussed at https://hackaday.io/project/9376-yet-another-discrete-clock/log/32201-how-to-divide-by-two) and something hit me...

This circuit has a problem : when the capacitor is too low and the button is pressed too long, it oscillates. Well, what if it became a feature ? :-) Just keep the button pressed and it will increase the time effortlessly. This reduces the number of buttons and circuits, from 6 to 3 :-)

I think I will add a capacitive coupling because the circuit is a bistable so a pulse would be generated for each transition, regardlessly of the current FF state.

Edit: wait, no need to add capacitive coupling/edge detection, if the charge and discharge resistors have a high ratio (like 10K/500K)