How to build an alarm like in a clock ?

[kash]

Hello,
Is there information how the alarms in alarm clocks work. I know the use
a piezzo devise for the sound, but what circuit or IC do they normally use
to generate the signal?
Thanks in advance

 

[Ian Stirling]

Hello,
Is there information how the alarms in alarm clocks work. I know the use
a piezzo devise for the sound, but what circuit or IC do they normally use
to generate the signal?

The unhelpfull and true answer is a clock IC, which is sometimes
a 4 bit microcontroller with special ROM programming.

Do you want to generate an alarm tone?

 

[kash]

The unhelpfull and true answer is a clock IC, which is sometimes

a 4 bit microcontroller with special ROM programming.

Do you want to generate an alarm tone?

Hello,
You know the 4 short beeps most digital alarm clocks make? this is what
I was thinking. If there is some IC that will do it without to many
complications, that will do for me.

 

[kash]

There are a few solutions, what sort of skills and equipment do you

havee?

I can buy any components I need from maplin/cpc (UK). Perhaps there
is a chip that would play a little tune, that should be fine as well.

 

[Frank Bemelman]

I can buy any components I need from maplin/cpc (UK). Perhaps there
is a chip that would play a little tune, that should be fine as well.

If you can find it, there's the old SAB600 from siemens.
Plays 'ding-dang-dong' and sounds very nice. Once used
for doorbels etc.

Example at:
http://www.peg.si/electro/gong.html

 

[kash]

Coudn't find it on maplin or fanell (uk), mind you will it work with a piezo?

 

[Rich Grise]

Hello,
You know the 4 short beeps most digital alarm clocks make? this is what
I was thinking. If there is some IC that will do it without to many
complications, that will do for me.

You could do it with a couple of 555s, (or a 556), a 4-bit binary
counter, and some gating logic. And yes, this can be made to drive
a piezo, and in fact, there are special piezos made that serve both
the function of the frequency-determining (feedback) element AND the
audio output transducer. They use one transistor and one resistor.
But you'd still have to generate and gate the pulses that turn the
beeper on.

Or you could get a beeping Sonalert, for about fifty bucks. =:-O

Good Luck!
Rich

 

[kash]

You could do it with a couple of 555s, (or a 556), a 4-bit binary

I am not sure what exactly you mean to be honest, can you draw
up some circuit.

counter, and some gating logic. And yes, this can be made to drive
a piezo, and in fact, there are special piezos made that serve both
the function of the frequency-determining (feedback) element AND the
audio output transducer. They use one transistor and one resistor.
But you'd still have to generate and gate the pulses that turn the
beeper on.

Maybe, I know nothing about piezos except that I really like there sound
much better than a speaker. Mind you, when I say that I am not too
bothered about the quality of the beeps this is not entirely true. I would
very much like to have this special sound quality which alarm clocks
have, as I am used to it, and because it sounds professional. Any idea
how this sound is generated?

Or you could get a beeping Sonalert, for about fifty bucks. =:-O

No, idea what this would be, though the price is ridiculous - out of
the question.

 

[kash]

For that, you could use the chip out of a musical birthday card.

Actually, I though of this idea, I may try it