Acoustic switch made easy

A couple of weeks ago, an LED panel for room lighting was assembled and it was decided to assemble an acoustic switch for it, and today I want to look at perhaps the simplest acoustic switch circuit.

Acoustic switch made easy


The scheme was found on one of the bourgeois sites and slightly altered. The device allows you to turn the power circuit on and off with a clap. I intend to use it to turn on the lights. The device is quite sensitive thanks to a double amplifier using low-power transistors. It responds to clap at a distance of 5 meters from the microphone. All parts were replaced with domestic ones.



The microphone amplifier uses domestic transistors of the KT 315 series with any letter or index. The final stage uses a powerful transistor switch based on a bipolar transistor of the KT 818 series, all other details are the same as in the original circuit. You can exclude the relay from the circuit and connect a load in its place, but this is only in cases where you need to control loads with power up to 12 volts; if you need to control loads with power from the network, you can’t do without a relay.At the moment of clap, the microphone receives the wave, and as a signal it is sent to a power amplifier, which alternately amplify the signal received from the microphone. The amplified signal arrives at the base of the switch, its magnitude is sufficient to trigger the transistor, and at this moment the junction of the transistor opens and conducts a current that powers the connected load or relay.



When assembling, observe all the ratings of the parts; even a slight slope can lead to abnormal operation of the switch. The device responds not only to pops, but also to low-frequency noise (powerful bass, etc.).




The supply voltage range is from 4 to 16 volts, power only from stabilized DC voltage sources and under no circumstances use switching power supplies, the device will not work with them!



For the trial version, the device was mounted mounted, then it will be transferred to the board, the main thing is that everything works without failures.

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Comments (31)
  1. Veent
    #1 Veent Guests 11 May 2012 21:26
    2
    Is the microphone capacitive? From a Chinese home phone and other similar equipment? Where did you get it from?
  2. bonod
    #2 bonod Guests 17 July 2012 15:10
    3
    You can find out the role of the diode and the Soviet analogue.
  3. jura1994
    #3 jura1994 Guests 14 November 2012 15:26
    2
    You can have a diagram and a list of parts used in the diagram
  4. kalistratovi4
    #4 kalistratovi4 Guests December 18, 2012 00:33
    0
    Does the switch only operate with a short click? How will it work when a cell phone rings?
  5. DiGriz
    #5 DiGriz Guests February 3, 2013 01:27
    3
    bonod,
    A relay coil is an inductance, and an inductance tries to keep the current flowing through it constant. Therefore, when the relay is turned off, the coil will be discharged by a reverse surge of high voltage, which can reach several sonnet volts, and in powerful relays - up to kilovolts. Transistors do not like such pulses very much and can burn out, and other devices connected to the power supply can also burn out.
  6. Sergey
    #6 Sergey Guests August 24, 2013 08:39
    0
    Is it possible to replace transistors from KT315 with KT3102?
  7. Vladislav
    #7 Vladislav Guests 29 January 2014 22:24
    1
    The diagram at the very top does not work for me. Draw the principle properly. I see you have two electrolytes there. What kind of capacity is it, which is near the microphone? I installed two kt315 and kt818b. I use a relay as a load. When I connect the power, the relay fires immediately. When there is a clap, the relay opens and immediately closes. I do not know what to do.
  8. Eugene
    #8 Eugene Guests 20 February 2014 21:45
    0
    Instead of electrolytes, it is better to use paper capacitors. And in addition it is better to install a thyristor.
  9. DN
    #9 DN Guests March 7, 2014 00:04
    0
    Quote: Vladislav
    When I connect the power, the relay fires immediately. When there is a clap, the relay opens and immediately closes. I do not know what to do.

    SIMILAR.
  10. mihail
    #10 mihail Guests March 15, 2014 00:16
    0
    you need to choose the right r2 r3