small timer (not mechanical)

[121ano]

I am looking for a small timer that I will buy with a "built-in time" that will come from the factory with 3 minutes (for example, it can be changed at the factory) and every first press will activate it (beep that we know we will press) and it will beep after 3 minutes 2-3 beeps . I need something very cheap and most "stupid" without a monitor without how much time remains and so on.
If there is such a size of a coin - I'll be happy
*pic att.
Thanks!!

 

[ads-ee]

I highly doubt you will find something like that you can purchase. What you are describing is something very specific to what you and only you need.

Possible options to get what you want...
a. build your own circuit to do this
b. contact a manufacture of timers and have them design one for you

Neither will be "cheap" (whatever cheap means to you) unless you plan on production runs of 10,000's

 

[121ano]

Thanks, i understand, but is that difficult to find such a thing? or to take it a part of some toy? im sure i ran into this in the past as a part of toy or something but cant remember where....
ill keep looking, it should be a very simple circuit to plan

 

[betwixt]

Designing a settable timer is very easy but you need to tell us more.

If there is such a size of a coin - I'll be happy

Are you saying the whole thing should be ~20mm across and a few mm thick? You wont get a beeper and LCD that small and still have space for three buttons.
Does is JUST beep or is it supposed to control something else? I mean should it operate a switch to control external equipment during the timing period.
How is it to be powered?

Brian.

 

[121ano]

Are you saying the whole thing should be ~20mm across and a few mm thick? yes You wont get a beeper and LCD that small and still have space for three buttons. no need 3 buttons-only 1 for start (even no button for stop) and no LCD
Does is JUST beep or is it supposed to control something else?no controling anything-just beep I mean should it operate a switch to control external equipment during the timing period.
How is it to be powered? smallest,chipest battry thier is

Brian.

Tnx Brain.

 

[121ano]

Are you saying the whole thing should be ~20mm across and a few mm thick? You wont get a beeper and LCD that small and still have space for three buttons.

yes, smallest as possiable without LCD just 1 button-start (not stop button cause after 3 min it should make 3 beep (for exaple)

Does is JUST beep or is it supposed to control something else? I mean should it operate a switch to control external equipment during the timing period. not operate anything, just simple beep
How is it to be powered? smallest, chipest button there is, if u have other idea-im open to hear

 

[betwixt]

If you want an LCD display - forget it, the cost of a custom LCD and zebra strip connectors would be prohibitive unless you were making these in 1,000+ quantities.

Without a display and provided you don't want a very loud beep, it is just about possible. I would suggest a 3V CR3032 type battery, a disc buzzer and a simple spring switch. Use a small PIC, maybe a 10F200 which in SMD package only has 6 pins, leave it powered up from the battery all the time and use the button to reset it. The software would then run a timer routine for the required time then it would drive anti-phase signals to the disc buzzer so it had ~6V of AC across it. After buzzing it could go to 'sleep' mode and draw almost nothing from the battery until reset again.

That uses one pin for reset, two for the buzzer and leaves one which you could use to select alternate beep pattern or maybe two different pre-set time intervals.

Brian.