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Gas Leak Detector

Monitor air quality with an MQ-2 sensor.

intermediate35 min

Components Needed

Arduino UNO

MQ-2 gas sensor

Buzzer

Red LED + 220Ω

Circuit Diagram & Wiring

Add your circuit diagram image here.

MQ-2 AO → A0, VCC → 5V, GND → GND.
Buzzer → pin 8.
LED → pin 9.

Arduino Sketch (.ino)

gas-detector.ino

const int THRESHOLD = <span style="color:#79b8ff">400span>;

void setup() {
  pinMode(<span style="color:#79b8ff">8span>, OUTPUT);
  pinMode(<span style="color:#79b8ff">9span>, OUTPUT);
  Serial.begin(<span style="color:#79b8ff">9600span>);
}

void loop() {
  int gas = analogRead(A0);
  Serial.println(gas);
  if (gas &gt; THRESHOLD) {
    tone(<span style="color:#79b8ff">8span>, <span style="color:#79b8ff">1500span>, <span style="color:#79b8ff">200span>);
    digitalWrite(<span style="color:#79b8ff">9span>, HIGH);
  } else {
    noTone(<span style="color:#79b8ff">8span>);
    digitalWrite(<span style="color:#79b8ff">9span>, LOW);
  }
  delay(<span style="color:#79b8ff">300span>);
}