MQ7  Carbon monoxide sensor  can detect CO gas and export both digital (0/1) and analog signals to Arduino. The TTL pin will export low voltage when CO GAS is detected. The analog pin will export voltage that is correlated to CO Gas density.

This project will use MQ7 sensor to detect CO Gas and export the gas density value to Arduino’s serial window.

2) Parts used in the project:

1 x Arduino UNO R3
1 x LED light;
1 x MQ-7  Co gas sensor
Jumper wires

3) Circuit Graph


4) Down Load Sample Code and load it onto Arduino.

5) Result;

Open Serial Window at the upper-right hand corner of the Arduino IDE, when no gas is detected, the sensor will export 1(high voltage) to the serial monitor and the LED will be turned on.


When smoke generated by the lighter nears the sensor, it will export 0(low voltage) and the LED will turn off.