SImple circuit for one beep (once) after pressing a push button

Thread Starter

visocor42

Joined Aug 12, 2020
1
Hello,

I am a student and I was wondering how I can make a simple circuit for making a one beep (not constant) after pressing a push button,
like when we are typing on our cell phones!
I would also like to use CR927 battery (3V) and a piezo buzzer.
Is it possible?

Thanks!
 

Bernard

Joined Aug 7, 2008
5,613
It is possible. Maybe a 7555, cmos version of 555, 2N3904 to drive piezo buzzer, + resistors & cap.
At 3 V buzzer will not be very loud.
From All Electronics, 3-18 VDC PIEZO BUZZER, FY14-G, 80 db @ 12V, 7 ma, CAT # SBZ-204, US $ 1.49.
Or add another 7555 & speaker
 
Last edited:

Marley

Joined Apr 4, 2016
356
I would look at the CMOS monostable IC CD4538 (or HEF4538) and possibly combine with a few other CMOS ICs.
They will work down to 3V supply and like most CMOS ICs use very little supply current when static (nothing changing). So good for coil cell operation.
See:- https://www.st.com/resource/en/datasheet/cd00000410.pdf
Easy to use the 4538 to generate a fixed length pulse on an input change. This can drive a small buzzer or control an oscillator (created with CMOS gates) that will drive a piezo speaker.
 

MrAl

Joined Jun 17, 2014
7,757
Hello,

I am a student and I was wondering how I can make a simple circuit for making a one beep (not constant) after pressing a push button,
like when we are typing on our cell phones!
I would also like to use CR927 battery (3V) and a piezo buzzer.
Is it possible?

Thanks!
Hi,

Here's an idea...

1. Use a momentary contact normally open pushbutton.
2. Press the button for the time you want it to beep.
3. Then let go.
:)
 

ci139

Joined Jul 11, 2016
1,675
there are a list of conditions you need to fix before starting with the design :
  • idle power draw --versus-- "wake on press"
  • duration of the beep
    • should it ring until the button is released
    • constant time on
      • what happens when there is multiple presses during sound.ON -event/-condition
      • ? maybe more
  • volume loudness/frequency of the beep
    • it's possible to buffer energy from cell button to capacitor for extra sound power -- such disables "too frequent" presses
  • start delay (if any)
  • physical space avail for the circuitry
  • ? etc. . . .
 

Bernard

Joined Aug 7, 2008
5,613
Simple circuit- low V piezo buzzer, 2- 10k resistors & capacitor. C- 5 to 25 uF. Works fine @ 12V, 5 uf, Mallory SONOLERT, & 2-10k Rs.
 
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