A Very Useful Timed Beeper Circuit Schematic


Posted on Feb 5, 2014

This circuit is intended for alerting purposes after a certain time is elapsed. It is suitable for table games requiring a fixed time to answer a question, or to move a piece etc. In this view it is a modern substitute for the old sandglass. Useful also for time control when children are brushing teeth (at least two minutes!), or in the kitchen, a


A Very Useful Timed Beeper Circuit Schematic
Click here to download the full size of the above Circuit.

nd so on. Pushing on P1 resets IC2 that start oscillating at a frequency fixed by R3 & C1. With values shown, this frequency is around 4Hz. LED D2, driven by IC1A & B, flashing at the same oscillator frequency, will signal proper circuit operation. SW1 selects the appropriate pin of IC2 to adjust timing duration: When the selected pin of IC2 goes high, IC1C drives Q1 and the piezo sounder beeps intermittently at the same frequency of the LED. After around 7. 5 seconds pin 4 of IC2 goes high and IC1D stops the oscillator through D1. If you want to stop counting in advance, push on P2. SW1 can be any type of switch with the desired number of ways. If you want a single fixed timing duration, omit the switch and connect pins 9 & 13 of IC1 to the suitable pin of IC2. The circuit`s reset is not immediate. Pushing P2 forces IC2 to oscillate very fast, but it takes some seconds to terminate the counting, especially if a high timer delay was chosen and the pushbutton is operated when the circuit was just starting. In order to speed the reset, try lowering the value of R5, but pay attention: too low a value can stop oscillation.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Ultrasonic switch circuit
    Audio Detector switch
    Flyback converter
    Carrier-Current Receiver For Data Transmission
    ac I need help matching parts
    Telephone Ringer
    Generating a Delayed Pulse Using The 555 Timer circuit
    Single 10 Shunt Fed Hartley Oscillator for 80 meter CW
    Receiver schematic design using MC3335PSSB
    SCA broadcast receiver circuit diagram
    As current feedback circuit of four b



    Top