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Gas & Smoke Sensors (MQ Series) | NexaLearn IoT Lab | NexaLearn

Safety Sensors25 دقيقة

Gas & Smoke Sensors (MQ Series)

Detecting toxic or flammable gases as part of an alarm system.

Lesson Content

The MQ series (e.g., MQ-2 for smoke and explosive gases, MQ-7 for carbon monoxide) contains an internal heater that warms a chemical material that reacts with the target gas, changing its resistance. The sensor draws relatively high current due to the heater.

Components Needed

Arduino Unoحساس غاز (MQ-2)

Wiring Notes

MQ sensors usually come with a module having both analog (A0) and digital (D0) outputs. Connect VCC to 5V (not 3.3V) because the heater requires power.

Code Example

void setup() {
  Serial.begin(9600);
}
void loop() {
  int gasLevel = analogRead(A0);
  Serial.print("Gas Level: ");
  Serial.println(gasLevel);
  if(gasLevel > 400) {
    Serial.println("ALARM: High Gas Concentration!");
  }
  delay(1000);
}

Common Mistakes

Not giving the sensor time to warm up (Burn-in Time). MQ sensors need several minutes of operation (and sometimes 24 hours for accurate first-time calibration) before their readings stabilize.

Next Lesson

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