GAS DETECTION – VENTILATION AND ALARM

The “Gas Detection – Alarm and Ventilation” project uses an Arduino and an MQ2 gas sensor to detect harmful gases around us. When gas is detected, a servo motor opens a door automatically, and a fan turns on to push the air out of the room. This project is a great and enjoyable way to learn about electronics and how sensors can be used in different applications.

Components used in this project are:

1. Arduino UNO with cable
2. Servo Motor SG-90
3. MQ2 gas sensor
4. 12 V DC fan
5. Red LED
6. Male to Male Jumper Wires x 15
7. Male to Female Jumper Wires x 3
8. Resistors  (10k ohm and 220 ohm)
9. N-Channel MOSFET 60V 30A

Featured Image:

Connection Pins with Arduino:

• Servo (Red -> 5V, Black ->GND , Orange -> 2)
• MQ2 (VCC -> 5V, GND ->GND, A0 -> A3)
• DC fan (Red -> Vin, Black -> Mosfet pin2)
• Mosfet (1st pin -> 10k resistor, 2nd pin -> DC fan black wire, 3rd pin -> GND)
• LED ( Anode -> 6, Cathode -> GND)

Circuit Diagram:

Code:

#include <Servo.h>
Servo myservo;
int pos = 0;

#define ledR 6
#define fan 5
#define sensor A3
#define servoPin 2

void setup() {
  Serial.begin(9600);
  myservo.attach(servoPin);
  pinMode(fan, OUTPUT);
  pinMode(ledR, OUTPUT);
  digitalWrite(sensor, LOW);
  myservo.write(0); // initially setting the servo posstion to 0, you can set according to your requirement.
}

void loop() {
  int value = analogRead(sensor);

  if (value > 380) {    //380 is the threshold, change according to your sensor
    digitalWrite(ledR, HIGH);
    digitalWrite(fan, HIGH);
    myservo.write(90);
    Serial.println(value);
    delay(500);

  }
  else {
    digitalWrite(fan, LOW);
    digitalWrite(ledR, LOW);
    myservo.write(0);
    Serial.println(value);
    delay(500);
  }
}