Smoke Detection

Just Do Electronics September 21, 2019

ABOUT THIS PROJECT

In this example, you will read the sensor analog output voltage and when the smoke reaches a certain level, it will make sound a buzzer and a red LED will turn on.

When the output voltage is below  that level, a green LED will be on.

PHOTO

How does it Work?

The voltage that the sensor outputs changes accordingly to the smoke/gas level that exists in the atmosphere. The sensor outputs a voltage that is proportional to the concentration of smoke/gas.

In other words, the relationship between voltage and gas concentration is the following:

The greaterthe gas concentration,the greaterthe output voltage

The lowerthe gas concentration,the lowerthe output voltage

With Lcd Diagram

COMPONENT

1.ARDUINO
2.MQ2 SENSOR
3.BUZZER
4.RED LED
5.GREEN LED
6. 220 OHM RESISTER - 3

Code

 
int redLed = 12;
int greenLed = 11;
int buzzer = 10;
int smokeA0 = A5;
// Your threshold value
int sensorThres = 400;

void setup() {
  pinMode(redLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(smokeA0, INPUT);
  Serial.begin(9600);
}

void loop() {
  int analogSensor = analogRead(smokeA0);

  Serial.print("Pin A0: ");
  Serial.println(analogSensor);
  // Checks if it has reached the threshold value
  if (analogSensor > sensorThres)
  {
    digitalWrite(redLed, HIGH);
    digitalWrite(greenLed, LOW);
    tone(buzzer, 1000, 200);
  }
  else
  {
    digitalWrite(redLed, LOW);
    digitalWrite(greenLed, HIGH);
    noTone(buzzer);
  }
  delay(100);
}
  

With Lcd
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

int redLed = 10;
int greenLed = 12;
int buzzer = 8;
int smokeA0 = A0;
// Your threshold value
int sensorThres = 100;

void setup() {
  pinMode(redLed, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(smokeA0, INPUT);
  Serial.begin(9600);
  lcd.begin(16,2);
}

void loop() {
  int analogSensor = analogRead(smokeA0);

  Serial.print("Pin A0: ");
  Serial.println(analogSensor);
  lcd.print("Smoke Level:");
  lcd.print(analogSensor-50);
  // Checks if it has reached the threshold value
  if (analogSensor-50 > sensorThres)
  {
    digitalWrite(redLed, HIGH);
    lcd.setCursor(0, 2);
    lcd.print("Alert....!!!");
    digitalWrite(12, LOW);
    tone(buzzer, 1000, 200);
  }
  else
  {
    digitalWrite(redLed, LOW);
    digitalWrite(12, HIGH);
    lcd.setCursor(0, 2);
    lcd.print(".....Normal.....");
    noTone(buzzer);
  }
  delay(500);
  lcd.clear();
}

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