MQ-9 gas sensor

Working Principle:

MQ-9 gas sensor has high sensitity to Carbon Monoxide, Methane and LPG. The sensor could be used to detect different gases contains CO and combustible gases, it is with low cost and suitable for different application.



  • Good sensitivity to CO/Combustible Gas.
  • High sensitivity to Methane, Propane, and CO.
  • Long life and low cost.
  • Simple drive circuit



  • Model: MQ-9
  • Type: Analog
  • Detecting Type: Carbonic Oxide(Co), Flammable Gas
  • Rated Voltage: DC 3-5V
  • Detecting Range: 10-1000ppm
  • Pin Definition: AO-analog Output,DO-Digital Output,GND- Ground,VCC-Voltage To Current Converter
  • Total Size: 35 x 20 x 21mm/ 1.4″ x 0.79″ x 0.83″ (L*W*H)
  • Net Weight: 8g


Link to Datasheet:




  • Domestic gas leakage detector
  • Industrial gas detector
  • Portable gas detector



  • Good sensitivity to CO/Combustible gas
  • High sensitivity to Methane, Propane and CO
  • Long life and low cost
  • Simple drive circuit



Connection with arduino:

  • Vcc: 5V
  • A0: Analog pin(A0 to A5 any)
  • D0: digital pin (2 to 13 any)
  • GND: GND

Arduino Code:

///Arduino Sample Code

void setup()


  Serial.begin(9600); //Set serial baud rate to 9600 bps


void loop()


int val;

val=analogRead(0);//Read Gas value from analog 0

Serial.println(val,DEC);//Print the value to serial port