# Newbie..need help with alarm clock

#### 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
10,965
Lets start by you showing us the circuit that you have made, then we can assist you with it.

#### Sugandh Sachdev

Joined Oct 15, 2015
6

#### Dodgydave

Joined Jun 22, 2012
10,965
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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#### Sugandh Sachdev

Joined Oct 15, 2015
6
yep

#### djsfantasi

Joined Apr 11, 2010
9,081
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.

#### 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
9,081
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?

#### 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
32,926
Just be sure you don't take it to school to show a teacher.

#### djsfantasi

Joined Apr 11, 2010
9,081
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.