How to use MQ2 gas sensor with Arduino | Step by step instructions

-

 


Hello, welcome back to another tutorial from the STEMx NG. In this tutorial, we will learn what is the MQ2 sensor and how it works with an Arduino. We have already described the MQ3 sensor in a previous tutorial. This sensor also works in the same way as the MQ3 sensor. Also, this MQ2 sensor can measure the amount of LP gas, smoke, carbon monoxide, and methane in the air. This tutorial explains how to make an LP Gas Measurement Project with Arduino step by step. We can buy this sensor in the market at a very low price.
The sensor is made of 6 pins with a stainless steel mesh cover on the outside. This mesh is designed so that only air particles can pass through. Also, this iron mesh connects to the sensor body using a stainless steel ring. These sensors belong to the metal oxide semiconductor type. That is, when a gas enters the sensor, the concentration of the gas is detected according to the degree to which the resistance of the sensor element changes.
Okay, now let’s talk about the internal structure of these sensors. The six legs here are connected to a sensor element from within. Also, two of these legs perform the function of heating this sensor’s element. These two legs are connected by a nickel-chromium coil. The other four legs are connected to the body of the sensor element using platinum wire. These give the signals.

Next, let’s talk about the sensor element. This sensor element is made of ceramics using aluminum oxide ceramics. It also has a tin dioxide coating on the outside. This tin dioxide element is more sensitive to combustible gases.

How does the MQ2 sensor work?

When this sensor is powered on, the tin dioxide heats up to a high temperature. At that point, oxygen is absorbed to the surface. Then, when the gas we are measuring is brought close to this sensor, it reacts with the tin dioxide to reduce the surface absorption of oxygen. After, the electrons are released into the tin dioxide. Then the current flows freely. In this case, the resistance difference can be received as an analog or digital value through the voltage divider circuit in the module to which this sensor is connected.


Okay, step by step we will learn how to connect this sensor with Arduino. The required components are as follows.

  • Arduino UNO board x 1 
  • MQ2 sensor x 1
  • LCD display x 1 
  • I2C module x 1 
  • Buzzer x 1
  • LED bulb x 1 
  • 180 ohm resistor x 1 
  • Breadboard x 1 
  • Jumper wires 

CODE
make sure you download I2C library — Download
/*MQ2 sensor with Arduino.
 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

#define LED 2
#define Buzzer 3
#define Sensor A1

void setup() {
  Serial.begin(9200);
  lcd.init();
  lcd.backlight();
  pinMode(LED, OUTPUT);
  pinMode(Buzzer, OUTPUT);
}

void loop() {
  int value = analogRead(Sensor);
  lcd.setCursor(0, 0);
  lcd.print("Value :");
  lcd.print(value);
  lcd.print("  ");

  if (value > 400) {
    digitalWrite(LED, HIGH);
    digitalWrite(Buzzer, HIGH);
    lcd.setCursor(0, 1);
    lcd.print("GAS Detected!");
  } else {
    digitalWrite(LED, LOW);
    digitalWrite(Buzzer, LOW);
    lcd.setCursor(0, 1);
    lcd.print("             ");
  }
}
Code explanation
Firstly, the I2C library is included. Later, an object was created for this library, which included the LCD width and length.
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
Secondly, the sensor, LED and buzzer pins are defined.
#define LED 2
#define Buzzer 3
#define Sensor A1
In the setup function. The LCD display is started. Also, the LED and buzzer pins are set as output pins.
void setup() {
  Serial.begin(9200);
  lcd.init();
  lcd.backlight();
  pinMode(LED, OUTPUT);
  pinMode(Buzzer, OUTPUT);
}
In the loop function, the sensor values are read and put into the integer variable. After, these values are printed on the LCD display.
int value = analogRead(Sensor);
  lcd.setCursor(0, 0);
  lcd.print("Value :");
  lcd.print(value);
  lcd.print("  ");
Then, these values are checked using the IF condition. If the sensor value is greater than 400, the LED and buzzer are activated. Also, printed on the LCD as “Gas detected”. Otherwise the LED and buzzer will be deactivated.
if (value > 400) {
    digitalWrite(LED, HIGH);
    digitalWrite(Buzzer, HIGH);
    lcd.setCursor(0, 1);
    lcd.print("GAS Detected!");
  } else {
    digitalWrite(LED, LOW);
    digitalWrite(Buzzer, LOW);
    lcd.setCursor(0, 1);
    lcd.print("             ");
  }
Lastly, select board and port. Afterward, upload this code to the Arduino board.<script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-7508976711535587"     crossorigin="anonymous"></script>


Comments

Post a Comment

Popular posts from this blog

-
Image
   Pumping ¶ The water pump is also a motor, which converts the mechanical energy of the motor or other external energy through a special structure to transport the liquid. Required Components 1. Arduino UNO 2. Jumper Wire                                                   3. L298N Module 4. Centrifugal Pump SCHEMATIC IN1~IN4 are the inputs of the L298N module, and OUT1~OUT4 are the outputs. A simple way to use them is: input high level for INx, OUTx will output high level; input low level for INx, OUTx will output low level. Connecting the two ends of the motor to OUT1 and OUT2, inputting opposite level signals for IN1 and IN2 will make the motor rotate. OUT3 and OUT4 can be used in the same way. Wiring L298N R3 Board Motor 12V 5V GND GND IN3 9 IN4 10 OUT3 one wire of the motor OUT4 one wire of the motor Code Note You can open th...
Read more
-
Image
   How to make a Bluetooth control 4WD car Now let’s see what other components are needed to create this smart car. Arduino Uno board x 1  Motor driver shield x 1  Bluetooth module x 1  Gear motor x 4  Robot wheels x 4 Dot board x 1  Li-ion battery x 2  Battery holder x 1 Jumper wires  THIS IS THE CIRCUIT DIAGRAM FOR THE CAR NEXT IS THE CODE OK, let’s look at the code below. First, you need to download the motor driver shield library. The complete program of this project below; # include <AFMotor.h> AF_DCMotor motor1 ( 1 ) ; AF_DCMotor motor2 ( 2 ) ; AF_DCMotor motor3 ( 3 ) ; AF_DCMotor motor4 ( 4 ) ; int Speed = 230 ; char value ; void setup ( ) { Serial . begin ( 9600 ) ; motor1 . setSpeed ( Speed ) ; motor2 . setSpeed ( Speed ) ; motor3 . setSpeed ( Speed ) ; motor4 . setSpeed ( Speed ) ; } void loop ( ) { if ( Serial . available ( ) > 0 ) { value = Serial . read ( ) ; } if (...
Read more
-
Image
                             Reaction Game ¶ Our body has many reaction times, such as audio RT, visual RT, touch RT, etc. Reaction times have many effects on our daily life, for example, slower than normal reaction times when driving can lead to serious consequences. In this project, we use 3 buttons and 2 LEDs to measure our visual reaction time. The serial monitor of the Arduino displays the message “waiting…” After pressing the Ready button, one of the two LEDs must light up randomly after a random time interval. It is important that the testee pushes the corresponding button as soon as possible. The Arduino records the time difference between when the LED lights up and when the person presses the corresponding button, and prints the measured response time on the Arduino serial monitor. Required Components In this project, we need the following components. 1. Arduino UNO Board 2. Jumper Wire 3. Brea...
Read more