8A8 MQ-7 CO Carbon Monoxide Coal Gas Sensor Module

Description

MQ7 sensor is a sensor having high sensitivity to carbon monoxide (CO).

The SnO2 semiconductor material is used in the MQ7 sensor for detecting gases. It has lower conductivity in clean air. It makes detection by method of cycle high and low temperature and detects CO when low temperature (heated by 1.5V). It helps in detecting the rising levels of gases through a rise in their conductivity. When the high temperature (is heated by 5.0V), it cleans the other gases adsorbed under low temperature. Users can convert the change of conductivity to gas concentration through a simple electronic circuit.

Datasheet

An MQ7 sensor has a wide array of applications such as:

• Domestic and industrial gas leakage detectors
• Industrial CO detector
• Portable gas detector

The applicability of an MQ7 sensor is enhanced by the following features:

• High-sensitivity CO and natural gas
• Good sensitivity to combustible gases in a wide range
• Long life
• Economy of cost
• Simple drive circuit

MQ7 carbon mono-oxide(CO) Gas Sensor specifications

• Operating Voltage: 5V 
• Operating Current: 150mA
• Operating Temperature: -20 to 50 degrees Celsius
• Concentration: 10-10000ppm

MQ7 carbon mono-oxide(CO) Gas Sensor pin diagram

Pin1: It is VCC Pin. It is used to connect 5V to the sensor.
Pin2: It is GND Pin. It is used to connect GND to the sensor.
Pin3: It is a digital output Pin. From this pin, you will get digital data HIGH/LOW.
Pin4: It is an analog output Pin. From this pin, you will get analog data.

Circuit diagram of MQ7 carbon mono-oxide(CO) Gas Sensor with Arduino

Pin connection of MQ7 carbon mono-oxide(CO) Gas Sensor with Arduino

• Connect the VCC pin of the sensor to the 5V pin of the Arduino UNO board
• Connect the GND pin of the sensor to the GND pin of the Arduino UNO board
• Connect the AO pin of the sensor to the A0 pin of the Arduino UNO board

Arduino code for interfacing MQ7 carbon mono-oxide(CO) Gas Sensor with Arduino

int sensorPin=A0;
int sensorData;
void setup()
{  
  Serial.begin(9600);   
  pinMode(sensorPin,INPUT);                         
 }
void loop()
{
  sensorData = analogRead(sensorPin);       
  Serial.print("Sensor Data:");

  delay(100);                                   
}

Arduino code working

Create a variable named sensorPin to the pin number of the Arduino UNO board where you have connected the AO pin of the sensor. In our case, it is A0 pin of the Arduino UNO board.

Create another variable named sensorData. We will use this variable to store the data that will be received by the Arduino from the sensor.

Inside the void setup block, set the baud rate for the serial communication and initiate the serial communication using Serial.begin() command.

Then use the pinMode() function to set the sensorPin as INPUT. The Arduino will use this pin to get the analog data from the sensor.

Inside the void loop() function, use sensorData variable to store the data that is received by the Arduino from the sensor. 

Then, print the data on the serial monitor using the print and println command.