Hi folks, I'm building a kind of clock that uses a motor to advance an lightweight indicator after being triggered by a pulse (or more probably, advancing the indicator after receiving 60 pulses, but I suspect that is another story).
I could do this easily using the ubiquitous arduino and a stepper, but using any kind of microprocessor seems like overkill, and I would strongly prefer to have this battery powered as it'll be wall-mounted and I don't want trailing wires, and I understand running steppers off batteries isn't very practical. Problem is I'm a programmer by trade and while logic is my bag, my electronics and my mechanics is probably schoolboy level.
What I am interested in is a circuit (AND/OR a mechanism) that will be, prompted by a pulse, turn a shaft a certain number of times then stop, but be left in a position to receive another pulse. Receiving another pulse during the powered-up phase won't happen so doesn't need to be catered for. The amount of turn almost doesn't really matter, and the speed doesn't really matter either.
My initial thoughts are to have a flip-flop (a 74HCT74B1R?) activated by the pulse, that switches a transistor to power a motor. On the motor gear head is a little stick that turns and eventually trips another circuit that generates another pulse turn the flipflop off. Now logically, I can see that working, but I can't seem to draw up a practical circuit that doesn't leave some part of the circuit energised in between movements, or that doesn't somehow block the next pulse.
Any ideas? I have search for prior art, but come up wanting.
I'm framing it in terms of a circuit here because this is an electronics forum, but I'd be even happier if it were a purely mechanical, or electromechanical solution. Springs and cams and whathaveyou.
Thanks!
Euphy