How to make an IoT based gas leakage monitoring system With Nodemcu and Blynk

Hello, welcome back. In this tutorial, we will learn how to make a gas leakage monitoring system using the Nodemcu board and Blynk app. This project mainly uses the MQ2 gas sensor and it’s based on IoT technology. That is, we can monitor everything in this security system on the mobile phone using the Internet. Also, we can do this project at a low cost. Therefore it can be used mainly for the home. This project will be more of a cover for accidents caused by gas leaks. Keep reading.

How does this security system work?

When power on this security system, The Nodemcu board connects to the interface created in the Blynk app via the Blynk cloud. Then the system should be activated by the button created in the Blynk app interface. In this case, when a gas leak occurs, it is detected by the MQ2 sensor. Then the buzzer and LED are activated. At the same time, it notifies your smartphone via a push notification. Also, we can see the gas values on the LCD and Blynk app interface. In the absence of a gas leak, the green LED bulb turns ON and operates normally in this security system.

Ok, let’s do this project step by step. The required components are given below.

• Nodemcu board x 1 — Our Store / Amazon
• MQ2 sensor x 1 — Our Store / Amazon
• LCD display x 1 — Our Store / Amazon
• I2C module x 1 — Our Store / Amazon
• Buzzer x 1 — Our Store / Amazon
• LED(Red,Green) x 2 — Our Store / Amazon
• 180-ohm resistor x 2 — Our Store / Amazon
• Breadboard x 1 — Our Store / Amazon
• Jumper wires — Our Store / Amazon

Disclosure: These Amazon links are Affiliate links. As an Amazon Associate, I earn from qualifying purchases.

Step 1

Firstly, identify these components.

Step 2

Secondly, connect these components. To do this, use the circuit diagram below.

Step 3

Thirdly, let’s set up the Blynk app interface.

• Firstly, download and install the Blynk app on your smartphone. Then, sign up for the Blynk app using your Gmail address. Now, click the New Project button.

• Secondly, enter your project name as you like. Then, select the device and connection. After, click the “confirm” button.

• Now we add the widget to the interface. To do so, click on the “+” icon in the corner.

• Then, add the styled button, Gauge, and Notification widgets to the interface. After, arrange these widgets as you like.

• OK, now click on the widgets one by one and change the settings. First, click the Widget button and name it as you like. Then set the output to V1 and mode to switch.

• Now, click the Gauge widget and name it as you like. Then change the input to V0 and the values from 0 to 100.

• Finally, click the Notification Widget and change the priority to HIGH.

Step 4

OK, the Blynk app is ready. Now, let’s create the program for this project. It is as follows.

• WIFI Library — Download
• Blynk Library — Download
• I2C Library — Download
• The complete program of this project – Download

/*GAS detector security system.
 * https://srituhobby.com
 */
 
#include <LiquidCrystal_I2C.h>
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

char auth[] = " ";// Enter your Auth token
char ssid[] = " ";//Enter your WIFI SSIS
char pass[] = " ";//Enter your WIFI password
BlynkTimer timer;
int pinValue = 0;

#define Buzzer D5
#define Green D6
#define Red D7
#define Sensor A0

void setup() {
  Serial.begin(9600);
  lcd.backlight();
  lcd.init();
  pinMode(Green, OUTPUT);
  pinMode(Red, OUTPUT);
  pinMode(Buzzer, OUTPUT);
  pinMode(Sensor, INPUT);
  Blynk.begin(auth, ssid, pass);
  timer.setInterval(100L, notifiaction);
}
BLYNK_WRITE(V0) {
  pinValue = param.asInt();
}

void notifiaction() {
  int sensor = analogRead(Sensor);
  Serial.println(sensor);
  sensor = map(sensor, 0, 1024, 0, 100);
  if (pinValue == 1) {
    if (sensor <= 50) {
      digitalWrite(Green, HIGH);
      digitalWrite(Red, LOW);
      digitalWrite(Buzzer, LOW);
      lcd.setCursor(0, 1);
      lcd.print("Gas value:Normal");
    } else if (sensor > 50) {
      Blynk.notify("Warning! Gas leak detected");
      digitalWrite(Green, LOW);
      digitalWrite(Red, HIGH);
      digitalWrite(Buzzer, HIGH);
      lcd.setCursor(0, 1);
      lcd.print("Gas value:High  ");
    }
    lcd.setCursor(0, 0);
    lcd.print("Value : ");
    lcd.print(sensor);
    Blynk.virtualWrite(V1, sensor);
  } else {
    digitalWrite(Red, LOW);
    digitalWrite(Buzzer, LOW);
    digitalWrite(Green, LOW);
    lcd.clear();
  }
}

void loop() {
  Blynk.run();
  timer.run();
}

Code explanation

Firstly, libraries are included. Also, an object is created for the I2C library, which includes the LCD width and length.

#include <LiquidCrystal_I2C.h>
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

Secondly, enter your Blynk Auth token and WIFI connection details.

char auth[] = "wVkwRQu8-_IMn-WtLtLXHnJ-NISyLkjW";// Enter your Auth token
char ssid[] = "srituhobby";//Enter your WIFI SSIS
char pass[] = "1234";//Enter your WIFI password

After, the LED, buzzer, and sensor pins are defined.

#define Buzzer D5
#define Green D6
#define Red D7
#define Sensor A0

In the setup function, the serial monitor, Blynk library, and LCD begin. After, the above pins are set as the output and input pins. Also, the main notification function is called. This function is described below.

void setup() {
  Serial.begin(9600);
  lcd.backlight();
  lcd.init();
  pinMode(Green, OUTPUT);
  pinMode(Red, OUTPUT);
  pinMode(Buzzer, OUTPUT);
  pinMode(Sensor, INPUT);
  Blynk.begin(auth, ssid, pass);
  timer.setInterval(100L, notifiaction);
}

This code retrieves values from the Button Widget.

BLYNK_WRITE(V0) {
  pinValue = param.asInt();
}

This is the main code part of this program. First, the values are taken from the sensor and these values are put into the integer variable. Later, these values are converted from 0 to 100. Next, the button value is checked. If the button value is 1, the main program is run. If the button value is 0, the system is turned off. Also, if the sensor value is less than or equal to 50, the green LED turns ON and prints on the LCD as “Gas value: Normal”. Then, if the sensor value is greater than 50. the red LED and buzzer activated. Also, the push notification is received on the smartphone as “Warning! Gas leak detected”.

void notifiaction() {
  int sensor = analogRead(Sensor);
  Serial.println(sensor);
  sensor = map(sensor, 0, 1024, 0, 100);
  if (pinValue == 1) {
    if (sensor <= 50) {
      digitalWrite(Green, HIGH);
      digitalWrite(Red, LOW);
      digitalWrite(Buzzer, LOW);
      lcd.setCursor(0, 1);
      lcd.print("Gas value:Normal");
    } else if (sensor > 50) {
      Blynk.notify("Warning! Gas leak detected");
      digitalWrite(Green, LOW);
      digitalWrite(Red, HIGH);
      digitalWrite(Buzzer, HIGH);
      lcd.setCursor(0, 1);
      lcd.print("Gas value:High  ");
    }
    lcd.setCursor(0, 0);
    lcd.print("Value : ");
    lcd.print(sensor);
    Blynk.virtualWrite(V1, sensor);
  } else {
    digitalWrite(Red, LOW);
    digitalWrite(Buzzer, LOW);
    digitalWrite(Green, LOW);
    lcd.clear();
  }
}

In the loop function, the Blynk library and timer are run.

void loop() {
  Blynk.run();
  timer.run();
}

Step 5

Lastly, select the board and port. After, upload this code to the Nodemcu board.

Now, click the run button on the Blynk app interface. Okay, enjoy this project. The full video guide is given below. So, we will meet in the next tutorial.

How to make an IoT based gas leakage monitoring system With Nodemcu and Blynk