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

商品說明

瓦斯氣體偵測感測器模組，在家庭和工業上可以針對特定瓦斯氣體洩漏進行檢測且十分有用。MQ-9氣體感測器對一氧化碳、甲烷、液化氣的靈敏度高，這種感測器可檢測多種含一氧化碳及可燃性的氣體，是一款適合多種應用的低成本氣體感測器。本模組偵測速度非常快，模組的靈敏度可以透過電位進行調整。

偵測濃度: 10-1000ppmCO;100-10000PPm Gas

Introduction

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.

Features

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

Application Ideas

• Gas leakage detecting
• Toys

Mechanic Dimensions

Electronic Characteristics

Usage

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.

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.

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() {
  Serial.begin(9600);
}
 
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(sensor_volt);
  Serial.println("V");
 
  Serial.print("R0 = ");
  Serial.println(R0);
  delay(1000);
 
}

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() {
  Serial.begin(9600);
}
 
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);
  sensor_volt=(float)sensorValue/1024*5.0;
  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.println(sensor_volt);
  Serial.print("RS_ratio = ");
  Serial.println(RS_gas);
  Serial.print("Rs/R0 = ");
  Serial.println(ratio);
 
  Serial.print("nn");
 
  delay(1000);
 
}

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

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.