Making Digital Clock Programmable

[nstahl]

I have this circuit I need to build that is a clock. I don't have the circuitry required for it to be programmable to a certain time. Included is my designs that I used. What would I have to add to it to make it programmable? A 555 chip?

 

[GreenGiant]

You should have a 555 in there somewhere anyways, or at least something to create the clock pulse.

The easiest way would be to have a button for each that will increment the binary output to the 7 segment drivers, basically something that will act like the pulse for minutes/hours

 

[nstahl]

Now how and where would I wire that?

 

[Miguel Lopez]

And you will need some way to neutralize the bouncing effect on the button. A bistable can do the job. The button should be in logical OR with the pulses which clock the hours and minutes.

 

[GreenGiant]

we need higher resolution pictures, and label which side is for hours which is for minutes.
As Miguel said you may need some protection against bounce, depending on the buttons and what your other circuitry is.

you may want an OR gate in there, that is one way of doing things, but thats not necessarily needed.

 

[nstahl]

I can't upload any more hi res. "photo2" was the hours and the first one I used for both the min and seconds. I took the output from QC on the second chip into Clk in the min circuit.