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Connecting Alarm feature to basic TTL digital clock

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New Member
I made a basic TTl digital clock referring the circuit that I attached
And I want to add a alarm feature to this.
I tried to find a circuit explaining how to design it.
But all the things that I found is made with not basic TTL. any help?



Well-Known Member
Most Helpful Member
It won't be trivial to use TTL to add an alarm. Things you will have to decide on include how to:
1) set and store the alarm time,
2) display what you are setting,
3) detect when clock time = set alarm time,
4) sound the alarm for a given period,
5) cancel the alarm.


Well-Known Member
Most Helpful Member
It could be easier than you think. A thimbwheel switch can set the alarm in BCD digits and use cascaded comparitors to determine when it's equal, now you will have at least a pulse when the comparitor is true.

The question is what to do with the pulse? Buzz forever? Buzz for 30 minutes? Snooze?

Now, I'm not sure what kind of clock this is, but the DIP switch seems to allow you to set individual digits. If it's a digital clock, there is no AM/PM indicator unless it uses 24 hr time.
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