Published July 5, 2021 © Apache-2.0

IoT Based Fire Alarm System Using NodeMCU ESP8266

This a multi sensor project where we will interface flame sensor and MQ2 gas sensor with ESP8266 NodeMCU.

IntermediateFull instructions provided1 hour27,554

IoT Based Fire Alarm System Using NodeMCU ESP8266

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

DFRobot FireBeetle ESP32 IOT Microcontroller (Supports Wi-Fi & Bluetooth)

DFRobot Gravity: Analog Gas Sensor (MQ2) For Arduino

DFRobot Gravity: Analog Flame Sensor For Arduino

Arduino UNO

Software apps and online services

Arduino IDE

Blynk

Story

In this blog we are going to build a fire alarm using multiple sensors.

This project will send an alert whenever it detects fire and smoke.

It has also connected with a buzzer and an LED which will act as a audio and visual indication for alert.

So lets quickly start building IoT based Fire Security Alarm System using NodeMCU.

Supplies

ESP8266 NodeMCU x 1
Flame Sensor x 1
MQ2 Smoke Sensor x 1
5V Buzzer x 1
Led Any color x 1
Transistor BC547 x 1
Resistor 1KΩ x 2
Jumper cables
Breadboard

Step 1: Flame Sensor

flame sensor

A Flame Sensor is a device that can be used to detect presence of a fire source or any other bright light sources. There are several ways to implement a Flame Sensor but the module used in this project is an Infrared Radiation Sensitive Sensor.

The module uses a LM393 comparator chip to provide a stable digital output signal. This comparator has a driving ability of 15 mA. This flame detector sensor can be used in different project including fire alarms and other fire detecting devices or projects.

Specifications:

LM393 comparator chip
Detection Range: 760 nm to 1100 nm
Operating Voltage: 3.3 V to 5 V
Maximum Output Current: 15 mA
Digital Outputs: 0 and 1Detection Angle: about 60 degrees
Adjustable sensitivity via potentiometer
LED lights indicators: power (red) and digital switching output (green)

Step 2: Smoke Sensor

In this project we are using a MQ2 smoke sensor.

This sensor can detect various gases including Methane, Butane and LPG. We are using a MQ2 gas sensor module in this project for better interface.

Specifications:

Operating Voltage is +5V
Can be used to Measure or detect LPG, Alcohol, Propane, Hydrogen, CO and even methane
Analog output voltage: 0V to 5V
Digital Output Voltage: 0V or 5V (TTL Logic)
Preheat duration 20 seconds
Can be used as a Digital or analog sensor
The Sensitivity of Digital pin can be varied using the potentiometer

Step 3: Connection

The connection is very simple here all the red and black wired are Vcc and GND connection.

You can also add an additional relay module to switch on exhaust or any other ac appliance.

You can modify the code and add it. We are using A0 pin of MQ2 gas sensor and D0 pin of Flame sensor.

Step 4: NodeMCU ESP8266

ESP8266 NodeMCU is an open source IoT platform.

It includes firmware which runs on the low cost Wi-Fi enabled ESP8266 Wi-Fi SoC from Espressif Systems, and hardware which is based on the ESP-12 module.

It has GPIO, SPI, I2C, ADC, PWM AND UART pins for communication and controlling other peripherals attached to it.

On board NodeMCU has CP2102 IC which provides USB to TTL functionality.

In this IoT Fire Alarm, we are using two GPIO pin to get the digital data from the flame sensor and gas sensor.

Step 5: Required Arduino Libraries

1 / 2

This code need 2 Arduino library. You can download Arduino IDE.

ESP8266
Blynk

Go to Sketch -> Include Library -> Manage Libraries

Now search for ESP8266 and install

Search for Blynk and install

Step 6: Code

You can download the code from below link and open it using Arduino IDE.

You have to unzip the the zip file after download and open it. Just add the Auth Token and your WiFi details in the code.

Step 8: Setting Up a Blynk Project

1 / 8 • blynk setup

Open the blynk app and tap on create a new project. Fill the details as shown below
You will receive the Auth token on your registered email id.
Tap on + sign to add below highlighted widgets
Add a notification widget as well.
Configure the gauge with below details.
Also configure the LED
Set the Value Display widget as per below settings
And finally your Blynk project setup is complete. You can rearrange the widgets and place them as you wish.

Step 9: Building and Testing

1 / 3

We have connected the components as per the circuit diagram and now its time to test the project.

For both the alert LED will glow and buzzer will start beeping.

You will receive below alert notification when flame sensor detects flame or fire.
Once the smoke sensor detects smoke and the value in the gauge goes beyond 500 then smoke alert will be detected. You can change the value in the code as per your need.

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Code

Code

//Nextpcb
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

int led = 13; // Connected to D7 pin of NodeMCU
int flame_sensor = 12; //Connected to D6 pin of NodeMCU
int buzzer = 4; //Connected to D2 pin of NodeMCU
int relay = 5; //Connected to D1 pin of NodeMCU
int smoke_sensor = A0; //Connected to A0 pin of NodeMCU
int temp_smoke_sensor;
int flame_sensor_read;

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "Auth Token"; // Enter Auth Token

// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "Your WiFi SSID"; //Enter the wifi name
char pass[] = "Your WiFi Password";// Enter the wifi password

void setup()
{
  pinMode(led, OUTPUT);
  pinMode(flame_sensor, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(relay, OUTPUT);
  pinMode(smoke_sensor, INPUT);
  
  digitalWrite(led, LOW);
  digitalWrite(buzzer, LOW);
  digitalWrite(relay, LOW);
  // Debug console
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
}

void loop() 
{
  flame_sensor_read = digitalRead(flame_sensor); //reading the sensor data on A0 pin
  Blynk.virtualWrite(V0, flame_sensor_read); //sending data to Blynk
  Serial.print("Flame Status:");
  Serial.println(flame_sensor_read);

  int led_status = digitalRead(led);
  if (led_status == HIGH)
  {
   Blynk.virtualWrite(V1, 255);
  }
  else
  {
   Blynk.virtualWrite(V1, 0);
  }
  
  temp_smoke_sensor = analogRead(smoke_sensor);
  Blynk.virtualWrite(V2, temp_smoke_sensor);
  Serial.print("Current Gas Level:");
  Serial.println(temp_smoke_sensor);
  if (temp_smoke_sensor > 500)
  {
    digitalWrite(led, HIGH);
    digitalWrite(buzzer, HIGH);
    digitalWrite(relay, HIGH);
    Blynk.notify("Alert Smoke Detected");  
    }
  else
    {
     digitalWrite(led, LOW);
     digitalWrite(buzzer, LOW);
     digitalWrite(relay, LOW);
    }

if (flame_sensor_read == 0)
    {
    //Blynk.virtualWrite(V1, 255);
    digitalWrite(led, HIGH);
    digitalWrite(buzzer, HIGH);
    digitalWrite(relay, HIGH);
    Blynk.notify("Alert Fire Detected");  
    }
  else
      {
      digitalWrite(led, LOW);
      digitalWrite(buzzer, LOW);
      digitalWrite(relay, LOW);
      }
      delay(500);
      Blynk.run();
}

Credits

NextPCB

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IoT Based Fire Alarm System Using NodeMCU ESP8266

Things used in this project

Hardware components

Software apps and online services

Story

Supplies

Step 1: Flame Sensor

Step 2: Smoke Sensor

Step 8: Setting Up a Blynk Project

Schematics

Schematics

Code

Code

Credits

NextPCB

Comments

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IoT Based Fire Alarm System Using NodeMCU ESP8266

IoT Based Fire Alarm System Using NodeMCU ESP8266

Things used in this project

Hardware components

Software apps and online services

Story

Supplies

Step 1: Flame Sensor

Step 2: Smoke Sensor

Step 8: Setting Up a Blynk Project

Schematics

Schematics

Code

Code

Credits

NextPCB

Comments

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