The Engineering Projects

Smoke Detector with Arduino & MQ2 Sensor

Hello everyone, I hope you all are  doing great. In today's tutorial, we are gonna have a look at How to design a Smoke Detector with Arduino. Its quite a simple project but if you are working on any security project then you must add this feature in it. You should also download this Gas Sensor Library for Proteus, and design its simulation. I will use gas sensor MQ2 for this project. I have purchased MQ2 Gas Sensor module as its quite easy to interface with Arduino. Arduino board I'm using is Arduino UNO. I have also designed an LPG Gas Leak Detect using Arduino using this MQ2 Sensor. So, let's get started with How to design Smoke Detector with Arduino & MQ2 Sensor.

Smoke Detector with Arduino & MQ2 Sensor

• First of all, we need to connect some jumper wires between Arduino and MQ2 smoke sensor shield.
• Here's the image of our Gas sensor and you can see, it has four pins in total.

• This gas sensor has four pins in total, which are:
  • Vcc: We need to provide +5V.
  • GND: We need to ground it.
  • D0: Digital Output.
  • A0: Analog Output.
• So now you will need four male to female jumper wires and connect them as shown in below figure:

• Sensor's pins are labelled on the back side and I have connected these four pins as follows:
  • White Wire: Vcc of Sensor connected with +5V of Arduino.
  • Black Wire: GND of Sensor connected with GND of Arduino.
  • Grey Wire: D0 of Sensor connected with Pin # 8 of Arduino.
  • Orange Wire: A0 of Sensor connected with A0 of Arduino.
• So, now let's design our code in Arduino software in which we will detect whether there's smoke around or not.
• I'm gonna use the analog output of our sensor and will first display the analog value in my Serial Monitor.
• I have used the below code, so copy it and upload in your Arduino board:

int Input = A0;
int SensorVal = 0;

void setup() {
  Serial.begin(9600);
  pinMode(Input, INPUT);
  Serial.println("Interfacing of Smoke Sensor with Arduino");
  Serial. println("Design by www.TheEngineeringProjects.com");
  Serial.println();
}

void loop() {

  SensorVal = analogRead(Input);
  Serial.println(SensorVal);
  delay(500);
}

• Now open the Serial Monitor of Arduino to check the analog values coming from our sensor.
• If everything goes fine then you will get something like this in your Serial Monitor:

• You can see we are getting the values in range of 420 to 450.
• You should read How to do Arduino Serial Communication, if you don't know how to get data serially.
• Now let's place a burning cigarette near it for smoke. (Cigarettes are injurious to health :P )
• When the sensor will sense smoke in its surroundings then its value will start to increase and in my case it reached to around 650.
• So, let's place a check in our Arduino coding to detect whether there's smoke or not.
• So add below code in your Arduino software and upload it to your Arduino board.

int Input = A0;
int SensorVal = 0;

int Check = 0;

void setup() {
  Serial.begin(9600);
  pinMode(Input, INPUT);
  Serial.println("Interfacing of Smoke Sensor with Arduino");
  Serial. println("Design by www.TheEngineeringProjects.com");
  Serial.println();
}

void loop() {

  SensorVal = analogRead(Input);
  if((SensorVal > 500) && (Check == 1))
  {
    Serial.println("Smoke Detected . . .");
    Check = 0;
  }

  if((SensorVal < 500) && (Check == 0))
  {
    Serial.println("All Clear . . .");
    Check = 1;
  }
  //Serial.println(SensorVal);
  delay(500);
}

• After uploading the code to Arduino, open your Serial Monitor.
• If everything goes fine then you will get something as shown in below figure:

• Now let me bring the cigarette close to get some smoke. (Cigarettes are injurious to health :P )
• You will get the warning as soon as it will detect smoke as shown in below figure:

• We got the detection of smoke in our Serial Terminal.

So, that's how we can easily design a Smoke Detector with Arduino & MQ2 Sensor. I think now you can quite easily design this smoke detector project at home. I hope you will enjoy it. Will meet you guys in next tutorial. Till then take care and have fun !!! :)