What is a sound sensor?Working,Pin Configuration and Its Applications

The human ear is capable of determining the volume of a sound. It can also tell the difference between two sound sources of varying strengths. Is there, however, a device that can perform the same function? The Sound Sensor is the perfect device to perform these function.This article discusses an overview of the sound sensor module, its working and applications..


The sound sensor is one of the most prominent sensors used in the electronics system nowadays. A sound sensor detects the intensity of sound and converts it into an electrical signal. This module includes a Microphone, a Peak detector, and an Amplifier. In this converter IC, we use LM393 Op-amp that is highly sensitive to sound. When the sensor detects a sound it is processed and the output voltage signal is provided to the microcontroller for further processing. This module can detect noise levels at a range of decibels at 3 kHz-6 kHz frequencies, approximately where the human ear is sensitive.

This sensor can detect noise levels in DB’s (decibels) at frequencies between 3 and 6 kHz, which is approximately where the human ear is sensitive. To measure the sound level, an android application called decibel meter is available for smartphones.


The specifications of the sound sensor include the following

  • IC Chip: LM393
  • Operating voltage: 3.3V-5V
  • operating current: 4-5 mA
  • Voltage gain 26 dB (v=6v, f=1khz)
  • Sensitivity of the microphone (1khz) :52 to 48 dB
  • The impedance of the microphone: 2.2k ohm
  • Frequency of microphone: 16 to 20 kHz
  • Signal to noise ratio: 54 dB
  • Signal output indication
  • The output is digital.
  • Single-channel signal output.
  • With the retaining bolt hole, convenient installation.
  • Output low level and the signal light when there is sound.
  • Dimension:45*17*9mm
  • Weight: 5gm


  • Pin1: (VCC) – 3.3V DC to 5V DC
  • Pin2 :( GND) – This is a ground pin
  • Pin3 :( DO) – This is an output pin
  • Pin4: ( A0 ) – Analog output pin


  • Microphone 
  • LM393 Voltage Comparator IC
  • NPN Transistor (marked as J6 on my board)
  • 10KΩ Resistors x 2 
  • 1KΩ Resistors x 3 
  • 10KΩ Potentiometer
  • 100nF Capacitors x 4 
  • LEDs x 2 
  • 510KΩ Resistor
  • 51KΩ Resistor


The working of the sound sensors is similar to that of the human ear. Because the human eye has a diaphragm, the diaphragm’s primary job is to convert vibrations into signals. Whereas in the sensor, the microphone uses the vibration generated and converts it into current or voltage. When the sound signal hits the diaphragm the magnet present within the sensor undergoes vibration, as a result, the current stimulates from the coil.

This converter IC consists of an inbuilt potentiometer to adjust the set point for the sound level. The analogue/digital output pin of the module is connected to the analogue/digital pin of the microcontroller. When the sound level exceeds a threshold value, the LED turns ON, and output sets to low.


  • Sound sensors are used for security systems.
  • Sound sensors are easily affordable.
  • Wireless sound sensors provide great freedom while speaking. Besides, it does not require cabling as compared to a wired mic.
  • Sound sensors work with speech recognition software where sound or speech is converted to text. This is also used by disabled people.


  • Sound files require more memory size.
  • The wireless microphones have a limited coverage range.
  • Due to battery life, the Operation time of the wireless microphone is limited.
  • Voice recognition software is not very accurate compared to manual typing. e.g it is difficult to distinguish between keywords like “some” and “sum”.


  • Security system for Office or Home
  • Spy Circuit
  • Home Automation
  • Robotics
  • Smart Phones
  • Ambient sound recognition
  • Audio amplifier
  • Sound level recognition (not capable to obtain precise dB value)


This Blog discusses an overview of the sound sensor. Hope this article helps you to understand the working principle, Interfacing and Applications of sound sensors.

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