Easy Basics: Project 016a Big sound sensor (KY 038 or KY 037)

of Acoptex.com in UNO

Basics: Project 016a

Project name: Big sound sensor (KY 038 or KY 037)

Attachments: analog pin sketch and digital pin sketch

In this project, you needed these parts :

1.Aruduino Uno R3 (you can also use the other version of Arduino)

2.Big sound (Michrophone sound) sensor (KY 038 or KY 037 or LM393 microphone sound sensor)

3.Arduino IDE ( you can download it from here  )

4.Jumper cables

5. Resistor 1 pc (220 Ohm)

6. Breadboard

7. LED 1 pc (red)


In this project we will learn how to use the microphone sound (big sound) sensor with the Arduino Uno board. A microphone sound sensor will detect the sound intensity of your surroundings and will light up an LED if the sound intensity is above a certain threshold.

Understanding the big sound (microphone sound) sensor

Sound Sensor is a component that receives sound waves and converts them into electrical signals. It detects the sound intensity in the ambient environment like a microphone does. 

The sensor has a capacitive electret microphone which is sensitive to sound. Sound sesnsors have a built-in potentiometer to adjust the sensitivity of the digital output pin. Sound waves cause the thin film of the electret to vibrate and then the capacitance changes, thus causing the corresponding voltage change. Since the change is extremely weak, it needs to be amplified. LM358 here is a power amplifier of 100 times gain. Connect the SIG output pin of the sound sensor to the Arduino Uno board and you can see the value of sound intensity on Serial Monitor, or display the wave forms on an oscilloscope if you have connected one.

We will use big sound sensor KY038  in this project.

You can read the specification of big sound sensor KY038 here.

Signals and contacts of big sound sensor KY038

Sound sensor KY038 has two outputs: 1. AO, analog output, real-time output voltage signal of the microphone; 2. DO, when the sound intensity reaches a certain threshold, the output high and low signal

The threshold-sensitivity can be adjusted via potentiometer on the sound sensor.

If you’re using the LM393 michrophone sound sensor, you should connect the OUT pin to an Arduino digital pin and GND and +5V pins to Ardino Uno board GND and 5V pins.

Signals and connections of LED

The operating voltage of the LED is 1.8V and the operating current is 10mA-20mA. The Arduino Uno board can supply 5V or 3.3V power. We will use 5V for this project, so the minimum resistance of the current limiting resistor should be (5 V to 1.8 V)/20 = 160 Om. The 220 Om offered in the kit is suitable and you can also choose other resistors that meet the condition. The larger the resistance is, the dimmer the LED will get.

Build the circuit

1.Analog pin used for sound sensor

2.Digital pin used for sound sensor

Step by Step instruction

  1. Plug your Adruino Uno board into your PC and select the correct board and com port
  2. Verify and upload the the sketch to your Adruino Uno.
  3. You can see the value of sound intensity on Serial Monitor. 
  4. When the volume reaches to a certain value, the LED attached to digital pin 12 on the Arduino Uno board will light up. 
  5. If the LED is not lighting up, you need to change the sensor sensitivity by rotating the potentiometer.


We have learnt how to use big sound sensor or michrophone sound sensor KY038 with Arduino board.


  • No libraries needed for this project


  • See attachments on the beginning of this project description.

Other projects of Acoptex.com
Easy Basics: Project 105a SIM900A GSM GPRS mini module of Acoptex.com in NANO 28-11-2019

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Published at 10-08-2017
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