Sound Activated Switch Circuit with PCB

This is Sound Activated Switch Circuit with PCB using IC-1458 and SCR-C106D It will work only if the loud is overdue. Ideal for player cameras Or you can bring to other use, It’s not Fouls, such as You may also be applied to a Burglar alarm circuit effectively, or applied to the alarm clock, when it has sounds high level. It operates using electricity tool.

The working of circuit

Sound SCR Switching circuit using IC-1458 and SCR-C106D
Sound SCR Switching circuit using IC-1458 and SCR-C106D

When you see advantages its, Might be a good idea now, come look the function of this circuit. As figure shown below. The sound signal is received by the condenser microphone Into the sound signal amplifier circuit That we choose IC op-amp No. MC1458 is Dual OP-Amp IC 8-DIP ST

Or other alternatives :
LF353 is IC Dual Low-Noise JFET OPAMP 3 MHz 8-pin DIP that better quality or
– TL072ACP is IC Dual J-FET Op-Amp 8 Pin DIP that cheap and well.
Because internal structure of the two op-amps, by the shape remains the same IC-741 which the op-amp IC is timeless. Make us cost-effective, convenient and economical with space.

Come see the circuit to continue. The first op-amp IC1a is designed to the gain about ten times, the output of IC1a will enter to pass the R5 to pin 6 of IC1b, that it is designed to gain about 100 times, So the all gain of this circuit is equal to 1,000 times.

The output from IC1b be fed through C2-4.7uF to trigger at pin G of SCR1-C106D works Immediately

Do you know: How SCR works

We use this circuit with the battery 9V, C3 provides a more stable and the C1-10uF placed to minimize disturbance, may cause the circuit to function errors.

How builds it

All devices can be installed onto the PCB, as shown in Figure 2 for the wire MIC, using a shield, to prevent a noise signal, which may make this works errors.

PCB Sound SCR Switch by IC 1458 & SCR C106D

When you installed all part correctly, then to try to attach the power supply to the circuit. And then use a small headphone drop across R7, if the circuit work correctly you will hear the sound from your headphone, next to connected the output to Set of flash lamp of a camera, Try to clap away from the MIC for about 2-3 inches. The flashlight works immediately but does not works Trial output terminal is connected to the light flash.


This circuit is designed primarily for use with a camera. However, you may be converted to another use, the output of the circuit to control the relay. The sensitivity of the circuit can be increased by reducing the value of R1 down to only 22K, it would be more sensitive times.

Stops problems with components and The project not work.
Although the circuits are is not the same. It can produce a sine wave signal as well.

Whistle activated light switch circuit with PCB

Surprisingly much, can turn on – shut down electric devices with a whistle sound
This is simple sound control circuits as the Whistle activated light switch circuit, that different from a little common circuit is requires high-frequency noise Such as whistle sound etc.

The heart of working in this circuit is IC1 (UM3763) that is designed for this particular work. The figure below shows a circuit in actual use.

How circuit works

whistle activated switch using um3763

The IC1 needs to use a voltage only 3 volts. However, for convenience to using with a voltage relays up to 12V. I so use the R3 and the ZD1 are a reduced voltage for IC1 to only 3 V, as need.

We use R6 to adjust the frequency of the oscillator circuit internal IC1. In this case, sets the frequency at 18Khz. Input frequency using be in the range 1/10 – 1/15 of the frequencies in above. In the frequency between 1.8kHz to 1.2kHz.

The Output of the circuit will change state each time to get input signal comes. The output signal at pin 8 goes to the base of Q1 to drive the output of the transistor Q2, which acts as a relay to drive the pace of the sound input signal.

Parts detail
IC1__________UM3763__Analog IC – Datasheet Reference
Q1___________NIO is BC547___45V 100mA NPN Transistor
Q2___________BC337 50V 800mA NPN Transistor
R1___________4.7K___1/4W Resistor
R2___________100ohm____1/4W Resistor
R3___________2.2K____1/4W Resistor
R4,R5___________1K____1/4W Resistor
C1___________0.0068uF 63V Polyester Capacitor
C2___________4.7uF 16V Electrolytic Capacitors
C3___________10uF 16V Electrolytic Capacitors
D1___________DRL is 1N4148 75V 150mA Diodes
ZD1__________Zener Diode 3V 0.5W
Microphone condenser

The UM3763 is a CMOS LSI circuit which contains analog signal amplifiers and frequency detector for driving motor.It is designed for use in electronic devices and other similar applications. It is packaged with 8 pins DIP.

How to build this project.

Figure 2 The PCB and components layout of this projects

You put all devices electronic together onto the PCB as circuit diagram correctly complete. As figure 2 You may change the R6 to 1M preset for can adjust circuit in the sound frequency range as you wanted in Easily.

When the circuit finish. Then, check for error again. Next, bring the power to the circuit immediately.

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can the output drive a dc motor and if it is yes, how the motor driver will work from the 9v dc source?

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