Project 2: Interfacing a MQ-4 sensor with Arduino Uno

In this article, we will talk about the MQ-4 sensor specifications and how to interface MQ-4 with Arduino Uno board.

The image shows a Methane Gas sensor board with MQ-4 sensor on-board. MQ-4 helps to sense the Methane gas concentration in the air. The MQ-4 can detect natural gas concentrations anywhere from 200 to 10000 ppm.

Electrical Specifications of the sensor:

Voltage: 5V

Signal Level: TTL

Output Type: Analog

The circuit diagram of the MQ-4 sensor is as follows:

If we see the above diagram of the MQ-4 sensor, we have Circuit voltage and Heating Voltage. Both of them can be 5V AC or DC as below specification shows from MQ-4 sensor datasheet.

When we use the carrier board, we need not bother about the Circuit and Heating voltage to be provided individually. We provide 5V as input to the carrier board and carrier board distributes to the sensor. The pin out of the carrier card is as follows.

The Analog output is to be connected to Analog pin of the Arduino board and VCC of 5V can be supplied from Arduino board as well.

ADC on Arduino Uno:

Arduino Uno board has 6 ADC channels with the 10-bit resolution ADC. The ATMega328P used on Arduino Uno has 8 ADC channels but the Arduino Uno board supports only 6 channels. The location of 6 Analog pins A0-A5 are highlighted in the below image of Arduino Uno.

Below image shows the Arduino Uno interfacing connectivity with the MQ-4 Sensor board.

Here is a video in our channel which explains the code and the set up:

https://youtu.be/-Uhmr4mA04s