### Project 16: Is there gas leakage

**1.Introduction**

This lesson is very much the same as the above one. The only difference is that we use a different gas sensor. The experiment principle can also be directly applied to factories in detecting harmful gases.

**2.Hardware required**

- EASY plug controller Board x1
- USB cable x1
- EASY plug cable x2
- Lighter x1 (not included)
- EASY plug Piranha LED Module x1
- EASY plug Analog Gas Sensor x1

Below is a brief introduction of this analog gas sensor.

![](media/image-20251126153411249.png)

This analog gas sensor - MQ2 is used in gas leakage detecting equipment in consumer electronics and industrial markets. This sensor is suitable for detecting LPG, I-butane, propane, methane, alcohol, Hydrogen and smoke. It has high sensitivity and quick response. In addition, the sensitivity can be adjusted by the potentiometer. Below are its specifications:

- Power supply: 5V
- Interface type: Analog
- Wide detecting scope
- Quick response and High sensitivity
- Simple drive circuit
- Stable and long lifespan
- Size: 56*20mm
- Weight: 8g

**3.Connection Diagram**

Now, connect the LED module to the D10 port of the controller board, and gas sensor to IIC port using the EASY plug cables.

![](media/image-20251126153522758.png)

**4.Sample Code**

Connect the board to your PC using the USB cable; copy below code into Arduino IDE, and click upload to upload it to your board.

```c
int gas_din=18;
int gas_ain=A5;
int led=10;
int ad_value;

void setup()
{
  pinMode(led,OUTPUT);
  pinMode(gas_din,INPUT);
  pinMode(gas_ain,INPUT);
  Serial.begin(9600);
}

void loop()
{ 
  ad_value=analogRead(gas_ain);
  if(digitalRead(gas_din)==LOW)
  { 
    digitalWrite(led,HIGH);
    Serial.println("Gas leakage");
    Serial.println(ad_value);
  }
  else
  {
    digitalWrite(led,LOW);
    Serial.println("Gas not leak");
  }
  delay(500);
}
```

**5.Result**

After all the above are done, you can see the power LED1 on the module is on, for LED2 on the module, you need to use a screw driver to adjust the knob for LED2 to be in a “off” state when it’s about to be turned on. Now, the piranha LED is off and open serial monitor, you can see it displays “Gas not leak”; then, turn on the lighter and turn off after a little while, place the lighter mouth into the sensor sensing area, you can see LED2 on the module and piranha LED are both on, and serial monitor displays “Gas leakage”.