MQ-4 Natural Gas Sensor Experiment Based on Arduino

Thisproject uses sensors to monitor indoor natural gas on the basis of Arduino, andwill make alarm if the natural gas leak exceeds the limit.

Material:

• MQ-4Natural Gas Sensor

• ArduinoUno with Network Screening

• Breadboard

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As a natural gas sensor, the MQ-4 Natural Gas Sensor is a fast and reliable sensor with a high sensitivity to natural gas and methane, also good sensitivity to propane and butane. This natural gas sensor has a long life and low cost and is widely used for gas leak detection. At the same time, two LED lights are used in the project to display the gas concentration:

• Green light: it means the natural gas concentration is belowthe critical value.

• Red light: alert! The natural gas concentration has exceeded the critical value.

The MQ-4Arduino sensor has four pins:

• Positive Vcc (+5V)

• Ground GND

• Digital output

• Analog output

Here is the wiring diagram:

In the schematic, there are two resistors connected to the Arduino digital pins and LEDs. The resistance is 220 Ohm

Here isthe code:

intpinRedLed = 11;
intpinGreenLed = 8;
intpinSensor = A5;
intTHRESHOLD = 250;
voidsetup() {
pinMode(pinRedLed, OUTPUT);
pinMode(pinGreenLed, OUTPUT);
pinMode(pinSensor, INPUT);
Serial.begin(9600);
}
voidloop() {
int analogValue = analogRead(pinSensor);
Serial.println("Val: " +analogValue);
digitalWrite(pinGreenLed, HIGH);
if (analogValue >= THRESHOLD) {
digitalWrite(pinGreenLed, LOW);
digitalWrite(pinRedLed, HIGH);
}
else {
digitalWrite(pinRedLed, LOW);
}
delay(5000);
}

The green LED remains light up unless the natural gas concentration exceeds the threshold, the red LED will lights up.