Grove Gas Sensor (MQ9) 瓦斯氣體偵測感測器瓦斯感測 一氧化碳感測器


Grove Gas Sensor (MQ9) 瓦斯氣體偵測感測器瓦斯感測 一氧化碳感測器

NT$300 NT$243 未稅


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偵測濃度: 10-1000ppmCO;100-10000PPm Gas

  • 高靈敏度可燃氣體偵測
  • 性能穩定,使用壽命長,成本低
  • 快速感測回應
  • 檢測範圍寬
  • 簡單的驅動電路



The Grove – Gas Sensor(MQ9) module is useful for gas leakage detecting(in home and industry). It can detect LPG, CO, CH4. Based on its fast response time. Measurements can be taken as soon as possible. Also the sensitivity can be adjusted by the potentiometer.

Twig-Gas Sensor.bmp



  • Wide detecting scope
  • Stable and long life
  • Fast response and High sensitivity

Application Ideas

  • Gas leakage detecting
  • Toys

Mechanic Dimensions

Electronic Characteristics

Items  Parameter name Min Type Max Unit
System Characteristics
VCC  Working Voltage  4.9 5  5.1 V
 PH  Heating consumption 0.5  340 mW
 RL  Load resistance  can adjust
 RH  Heater resistance  33Ω±5%  Ω
 Rs Sensing Resistance  2  20000   Ω
 CO/CH4/LPG Scope Detecting concentration  200  1000/10000/10000   ppm


Suggest Reading for Starter

Download Arduino and install Arduino driver
Getting Started with Seeeduino
How to choose a Gas Sensor
What’s LEL

Hardware Installation

Grove products have a eco system and all have a same connector which can plug onto the Base Shield. Connect this module to the A0 port of Base Shield, however, you can also connect Gas sensor to Arduino without Base Shield by jumper wires.

Arduino UNO Gas Sensor
Analog A0 SIG

You can gain the present voltage through the SIG pin of sensor. The higher the concentration of the gas, the bigger the output voltage of the SIG pin. Sensitivity can be regulated by rotating the potentiometer. Please note the best preheat time of the sensor is above 24 hours. For the detailed information about the MQ-9 sensor please refer to the datasheet.

Read Gas Sensor data.jpg

How to use

There’re two steps you need to do before getting the concentration of gas.

First, connect the module with Grove Shield using A0 like the picture above. And put the sensor in a clear air and use the program below.

void setup() {
void loop() {
  float sensor_volt; 
  float RS_air; //  Get the value of RS via in a clear air
  float R0;  // Get the value of R0 via in LPG
  float sensorValue;
/*--- Get a average data by testing 100 times ---*/   
    for(int x = 0 ; x < 100 ; x++)
    sensorValue = sensorValue + analogRead(A0);
  sensorValue = sensorValue/100.0;
  sensor_volt = sensorValue/1024*5.0;
  RS_air = (5.0-sensor_volt)/sensor_volt; // omit *RL
  R0 = RS_air/9.9; // The ratio of RS/R0 is 9.9 in LPG gas
  Serial.print("sensor_volt = ");
  Serial.print("R0 = ");

Then, open the monitor of Arduino IDE, you can see some data are printed, write down the value of R0 and you need to use it in the following program. During this step, you may pay a while time to test the value of R0.

Second, put the sensor in one gas where the environment you want to test in. However, don’t forget to replace the R0 below with value of R0 tested above

void setup() {
void loop() {
  float sensor_volt;
  float RS_gas; // Get value of RS in a GAS
  float ratio; // Get ratio RS_GAS/RS_air
  int sensorValue = analogRead(A0);
  RS_gas = (5.0-sensor_volt)/sensor_volt; // omit *RL
  /*-Replace the name "R0" with the value of R0 in the demo of First Test -*/
  ratio = RS_gas/R0;  // ratio = RS/R0 
  Serial.print("sensor_volt = ");
  Serial.print("RS_ratio = ");
  Serial.print("Rs/R0 = ");

Now, we can get the concentration of gas from the below figure

GAS Sensor 7.png

According to the figure, we can see that the minimum concentration we can test is 200ppm and the maximum is 10000ppm, in a other word, we can get a concentration of gas between 0.02% and 1%. However, we can’t provide a formula because the relation between ratio and concentration is nonlinear.


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