# Newbie..need help with alarm clock

Thread Starter

#### Sugandh Sachdev

Joined Oct 15, 2015
6
I am a newbie with electronics and as a project I took alarm clock. I have made the digital clock using Binary counters and 7 segment display but I have no idea how to enable alarm system in it. Can you please at least give me an idea how it would be done or where to start from?

#### Dodgydave

Joined Jun 22, 2012
10,050
Lets start by you showing us the circuit that you have made, then we can assist you with it.

Thread Starter

#### Sugandh Sachdev

Joined Oct 15, 2015
6

#### Dodgydave

Joined Jun 22, 2012
10,050
I take the clock starts at Zero and goes upto 12-00-00, do you want to have an output at a certain time, say 07-30-00,?

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Thread Starter

#### Sugandh Sachdev

Joined Oct 15, 2015
6
yep

#### djsfantasi

Joined Apr 11, 2010
7,828
And how are you going to input the alarm time? Sets of SPST switches for each digit? A four position DIP switch? A thumb wheel BCD switch? The last is easiest, but is expensive.

Thread Starter

#### Sugandh Sachdev

Joined Oct 15, 2015
6
And how are you going to input the alarm time? Sets of SPST switches for each digit? A four position DIP switch? A thumb wheel BCD switch? The last is easiest, but is expensive.
dip switch

#### djsfantasi

Joined Apr 11, 2010
7,828
dip switch
So you set a DIP switch for each digit. What do you want to compare it to? For example, consider just the 10s of minutes digit?

By the way, have you simulated your circuit?

Thread Starter

#### Sugandh Sachdev

Joined Oct 15, 2015
6
So you set a DIP switch for each digit. What do you want to compare it to? For example, consider just the 10s of minutes digit?
OHH I think I got it.
Compare it with the current time. when the the current time and the input in dip switch matches a buzzer is activated.
Thanks for the help

#### crutschow

Joined Mar 14, 2008
27,725
Just be sure you don't take it to school to show a teacher.

#### djsfantasi

Joined Apr 11, 2010
7,828
OHH I think I got it.
Compare it with the current time. when the the current time and the input in dip switch matches a buzzer is activated.
Thanks for the help
Have you simulated this? I had a reason for asking before.

I suggest you do, even if you run through it manually. I have a suspicion...

Your minutes and seconds may only count up to 58, leaving you a a few seconds short of a minute and a few minutes short of an hour...
It will be a fast clock. Depending on what you're using it for, it could be a good thing or a bad thing.

Thread Starter

#### Sugandh Sachdev

Joined Oct 15, 2015
6
Yes. It works fine till 60 minutes. The hours one I haven't really simulated that