Decibel Meter using Sound Module & Arduino with LCD Display

Decibel Meter using Sound Module & Arduino (Last Updated On: December 1, 2018)


Decibel Meter using Sound Module & Arduino with LCD Display has been designed specifically for detecting the level of sound produced from any source and its intensity as well. The LCD panel directly displays the information about sound level in numbers. The sound is distinguished as low, medium and high level sound on the basis of number. LED by glowing gives the indication that noise is so high. The set up is absolutely self contained and requires no other apparatus.

Components Required

  1. ATmega328 Microcontroller or Arduino Board
  2. Arduino Sound Module – (Buy Online from Amazon)
  3. 16*2 LCD
  4. Resistors: R1=100E, R2=1M, R3=330E
  5. Ceramic Capacitors: C1=C2=22pF
  6. Electrolytic Capacitors: 10uF/63v
  7. 16 MHz Crystal Oscillator
  8. Tactile Switch
  9. +5V Power supply

Decibel Meter using Sound Module & Arduino

So here we will learn how to interface Sound Module with Arduino. For breadboard assembly of the project with arduino, you can assemble like this.

Decibel Meter using Sound Module & Arduino
But if you want to reduce the cost and use it with ATmega328 microcontroller you can use this circuit diagram. Here you will learn how to detect ambient sound and how to handle the signal generated by this module. This board along with the microphone, has a small built-in amplifier (integrated circuit LM393), because only the microphone would not be able to send data for Arduino. The connection scheme is very clean, composed of only 3 pins: Vcc, GND and S (signal). In the middle of the plate, there is a potentiometer for sensitivity adjustment.

Decibel Meter using Sound Module & Arduino

The board works with 5V voltage, and the signal pin should be connected preferably to an analog port of Arduino, since the generated signal is variable, and thus we can see the different levels of noise picked up by the microphone. The circuit tests will consist of the module Sound Sensor , plus the display 16×2 LCD. The display at its top, will show the sound level (Low, Medium and High), and bottom , a bar that will follow in real time the sound level detected by the microphone will be shown:

Arduino Sound Module

➡ Main chip: LM393, electret microphone
➡ Working voltage: DC 4 ~ 6V
➡ Has the signal output instructions
➡ Single signal output.
➡ Effective signal output for low level.
➡ Output low level and signal light will on when there has voice.
➡ Can be used for sonic lamp, with photosensitive sensors act as sound and light alarm, also can be used in the occasion of voice control and sound detection.
➡ Circuit boards output switch value.

Decibel Meter using Sound Module & Arduino

Specifications & Pin Details
The simple specifications of sound module from left to right first pins are as follows:
Pin 1 VCC :4V to 6V DC
Pin 2 GND :GND
Pin 3 D0 :Digital Out
Pin 4 A0 :Analog Out

Sound detection sensor module for arduino detects whether sound has exceeded a threshold value. Sound is detected via microphone and fed into an LM393 op amp. The sound level set point is adjusted via an on board potentiometer. When the sound level exceeds the set point, an LED on the module is illuminated and the output is sent low.

About Programme & Code Uploading

The ATmega328 microcontroller is programmed using Arduino language. The input output pins are not selected on the behalf of Atmega328 pins but on the behalf of Arduino analog and digital pins. Either use Arduino Board for this project. Or simply assemble the circuit as shown in figure. This is done to reduce cost. Programme for both the circuit is same.

For above circuit, a fresh new ATmega328 microcontroller with bootloader is inserted on Arduino Board and code is uploaded. Remove the microcontroller from board and insert in the circuit given above.

Source Code/Program:

The source code for Decibel Meter using Sound Module & Arduino with LCD is given below.

#include <LiquidCrystal.h>
LiquidCrystal lcd(7,8,10,11,12,13);

int num_Measure = 128 ; // Set the number of measurements   
int pinSignal = A0; // pin connected to pin O module sound sensor  
int redLed = 5; 
long Sound_signal;    // Store the value read Sound Sensor   
long sum = 0 ; // Store the total value of n measurements   
long level = 0 ; // Store the average value   
int soundlow = 40;
int soundmedium = 500;
void setup ()  
  pinMode (pinSignal, INPUT); // Set the signal pin as input   
  Serial.begin (9600); 
void loop ()  
  // Performs 128 signal readings   
  for ( int i = 0 ; i <num_Measure; i ++)  
   Sound_signal = analogRead (pinSignal);  
    sum =sum + Sound_signal;  
  level = sum / num_Measure; // Calculate the average value   
  Serial.print("Sound Level: ");
  lcd.print("Sound Level= ");
  Serial.println (level-33);  
    lcd.print("Intensity= Low");
  if(level-33>soundlow && level-33<soundmedium)
    lcd.print("Intensity= High");   
  sum = 0 ; // Reset the sum of the measurement values  

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Testing of the Circuit

The Circuit for Decibel Meter using Sound Module & Arduino should be tested as below:

  1. Switch on the power supply of the training board so that LCD will light up.
  2. Intially when everything is silent number 0 or 1 will be displayed on LCD indication LOW.
  3. Turn on the music player and bring the module near to the speaker source, you will observer change in number and also level shifting from low to medium or high.
  4. Similarly turn the volume up or down and check the level of sound. When extremly high volume is detected red led will glow indicating alert.

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