MQ8 - Hydrogen Gas Sensor Module

The Hydrogen Gas Sensor Module most used with Arduino is the MQ8 sensor. It is designed to detect hydrogen (H₂) gas in the air and is often used in gas leak detection, hydrogen-powered systems, and safety monitoring setups. The MQ-8 gas sensor is highly sensitive to hydrogen and less sensitive to alcohol and cooking fumes. It could be used in gas leakage detection appliance in domestic and industry. 

Technical Specifications:

• Operating Voltage: 5V DC
  
• Detection Range: 100 – 10,000 ppm H₂
  
• Gas Detected: Hydrogen (H₂)
  
• Analog Output (A0): Varies with gas concentration
  
• Digital Output (D0): HIGH/LOW based on threshold (set via potentiometer)
  
• Heater Power: ~800–900 mW
  
• Warm-up Time: ~1–5 minutes for accurate readings

Pinouts:

Connection with Arduino:

Module	Arduino UNO
VCC	5V
GND	GND
A0	A0
D0	D2(Optional)

 

Sample code:

Analog reading:

int mq8Pin = A0;  // MQ8 A0 pin connected to Arduino A0

void setup() {
  Serial.begin(9600);  // Initialize Serial Monitor
}

void loop() {
  int gasValue = analogRead(mq8Pin);  // Read analog value
  Serial.print("Hydrogen Gas Level: ");
  Serial.println(gasValue);           // Print value to Serial Monitor
  delay(1000);  // 1 second delay
}

Add Buzzer for Gas Leak Alert

int mq8Pin = A0;
int buzzerPin = 8;
int threshold = 400;  // Adjust this value after testing

void setup() {
  Serial.begin(9600);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  int h2Level = analogRead(mq8Pin);
  Serial.print("H₂ Level: ");
  Serial.println(h2Level);

  if (h2Level > threshold) {
    digitalWrite(buzzerPin, HIGH);  // Turn buzzer ON
  } else {
    digitalWrite(buzzerPin, LOW);   // Turn buzzer OFF
  }
  delay(500);
}