How to Use MQ2 Gas Sensor - Arduino Tutorial

The MQ series of gas sensors use a small heater inside with an electro-chemical sensor. They are sensitive for a range of gasses and are used indoors at room temperature. The output is an analog signal and can be read with an analog input of the Arduino.

The MQ-2 Gas Sensor module is useful for gas leakage detecting in home and industry. It can detect LPG, i-butane, propane, methane ,alcohol, hydrogen and smoke.

Some modules have a built-in variable resistor to adjust the sensitivity of the sensor.

Note: The sensor becomes very hot after a while, don't touch it!

In this tutorial we will use the serial monitor of Codebender (or Arduino IDE) to see how the sensor acts in variable gasses.

So, let's get started!

Step 1: What You Will Need

For this tutorial you will need:

• Arduino uno
• Breadboard
• MQ-2 Gas sensor module

Step 2: The Circuit

The connections are pretty easy:

• Vcc to Arduino 5V pin
• GNG to Arduino GND pin
• Output to Arduino Analog A0 pin

Note: The sensor becomes very hot after a while, don't touch it!

Step 3: The Code

Here's the code, embedded using Codebender!

Try downloading the codebender plugin and clicking on the Run on Arduino button to program your Arduino with this sketch. And that's it, you've programmed your Arduino board! Press connect button to start serial communication with your Arduino board.

Now you can try this:

Take a lighter and press the button to release gas near the sensor. Observe values on serial monitor.

You can keep playing with that by clicking the "Edit" button and start making your own modifications to the code.

Step 4: Well Done!

You have successfully completed one more Arduino "How to" tutorial and you learned how to use the MQ-2 Gas sensor with Arduino.

Tip: You can use this tutorial to read values from all MQ gas sensors (MQ-2, MQ-3, MQ-4, MQ-5, MQ-6, MQ-7, etc)

I hope you liked this, let me know in the comments.
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Comments

[nivekkan]

Bro u saved my assignment. thanks

[SujanD1]

do we have to heat the sensor externally for some time before taking reading???

[technoelectronics44]

if it is normal temperature no problem, if you increase the temperature beyond the limits it is getting damage

[fizahsarkawi93]

can i have the schematic sketch pls ?

[technoelectronics44]

you can find in Technoelectronics44

[BallscrewBob]

What about the fourth pin ?

[technoelectronics44]

it has VCC,GND,D0,A0 pins.
in this article A0 pin is interface with analog pin of microconteroller , if you want to interface with digital pin of microcontroller then you can use D0 pin of sensor

[pfeerick]

The forth pin (the unused one in this project) will be the digital/TTL pin, that will either be high (1) or low (0), and the trigger point is set using the potentiometer on the other side. Useful when you want to simply trigger when a set amount of gas is present.

[TarekS30]

Can i supply this sensor with a 9V battery?

[Mickey The Maker]

You can supply the adrinio with a 9V battery.

[nishanthgadam]

Thanks for sharing this article nice info
gas transmitters

[HanNaKim02]

does we need to combine the lcd coding with this MQ-2 coding to get the value of smoke? or it just appear on lcd when we set it up on the breadboard?

[Ankitp1995]

i have MQ2 and MQ 4 sensor and arduino uno, i want to check methane composition in biogas. i want codes please help me

[AADITYA DEWANGAN]

How this programme is valid for aal aurdino board

[Rahul tripathi13]

Can we attiny 85 instead of arduino

[LukasS8]

Hey could one arduino power all MQ Sensors (MQ-2,3,4,5,6,7..) or would it need to much current?

[codebender_cc]

I don't know... maybe you will need an external power source.

[JAK101]

You can only use an external power source to power the digital IO pins. External power for analog is not recommended due to noise issues.

[ChoudharyA2]

Noise Issue?? Can you explain

[TheMake]

maybe you could us a voltage regulator or same what you said...... :)