Digital 7 segment clock with trigger

[frankwas]

Hi All!

Thanks to all for your input on my previous project's questions. Now I have a new one, very small actually and I'm sure a lot of you will be able to solve it within minutes.

Speaking of minutes, I would like to build a digital 7 segment clock, from a kit or whatever, then have it switch on a relay momentarily (for about 1 - 2 seconds) for every minute it advances in time and then carrry on as usual.

Is this easy or diff to build?

Thanks.

Francois.

[audioguru]

Hi Francois,
Pick a clock circuit that doesn't multiplex the display.
An electronic clock doesn't have an output that gives a pulse each minute. You would need to take a signal from each segment of the lowest minutes digit and capacitor-couple them to an OR gate. Then make a 2-seconds monostable which is triggered by the gate.

Or you could use a divide-by-60 counter that is clocked by the colon that blinks each second. It would trigger the monostable.