How to use gas sensors with Arduino || Arduino tutorial

In this tutorial I'm demonstrating how to use MQ-2/MQ-5 gas sensors with Arduino. These little devices may be used in gas leakage detectors.
The MQ-2 is suitable for detecting LPG, i-butane, propane, methane, hydrogen and even smoke.
The MQ-5 detects LPG, natural gas and town gas.
Many other gas sensors can be used in exactly the same way, e.g. MQ-3, MQ-6 or MQ-135. Just read the datasheet, use the appropriate load resistor and experiment with the "sensorValue" in my Arduino code.
Project page - you can download Arduino code and see schematic used in this video here:
ElectronFun.com/project_2.php
Datasheets:
MQ-2: www.pololu.com/file/0J309/MQ2...
MQ-5: www.parallax.com/sites/defaul...
See how to calibrate an MQ-2 gas sensor:
• How to calibrate an MQ...
See all my Arduino tutorials here:
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Video, edit, voice by Chris Lorkowski
Music composed and performed by Bensound - Happiness
www.bensound.com
Sound effects recorded by Mark DiAngelo - Blop
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[@zorrog.2947]

Hi there, I'd like to build a CO2 gas sensor using an MQ-135 gas sensor, for my environmental science class. How can I adapt this project to an MQ-135 sensor? Also, the links to your datasheets don't seem to work. Can I get access to your datasheets? How can I create a similar datasheet for an MQ-135 sensor? Any assistance is most appreciated. Cheers!

[@ElectronFunCom]

You don't have to change anything in this project, if you want to get a value between 0 and 1023. I fixed the datasheet links, thanks for letting me know they were broken.

[@naveenmittal]

hi, i want to measure air quality at home and thinking of getting MQ-135 but i am not sure if sensitivity is highly enough to detect low gas level. i know that CO should be under 6 ppm in healthy air quality, will this sensor measure that? thanks in advance

[@ElectronFunCom]

+naveen mittal Hi, I don't know the exact answer to your question. To measure gas concentration in ppm you would need a calibrated sensor. I know that these MQ type sensors are not very accurate, I wouldn't trust them so much.

[@rich1051414]

If you want to use this properly, you need to calibrate every startup, after warming up for 3 minutes, expose to open air, and then in your code, zero out the value. Then only measure based on the offset. This makes the readings more sane and accurate. Otherwise you will notice drift on every startup depending on the material composition of the heater and materials near it, as they will off-gas differently as they age, and should be discounted from the readings.

[@saularias5308]

Very good video. Simple and clear explanations. My son and I bought an MQ-4 yesterday and now I understand how to connect it to the Arduino. Thank you very much!

[@ElectronFunCom]

+Saul Arias Thanks a lot! Have fun with your project :)

[@y4khalil]

Hello, thanks for this wonderful video. Can I use any of the MQ- series to measure the quantity of gas inside the storage tank?

[@gopikrishnanr8379]

Thanks for posting this video.. I found it very useful. Have you though not connecting the Audrino directly to sensor and use wifi to exchange messages?

[@ralfsdw]

You need something to read the analog values from the sensor before transmitting them over wifi anyway

[@gopikabg5403]

The values in serial monitor are voltage values.Am i correct?I want resistance values too.Is it possible?

[@ElectronFunCom]

Yes, these are voltage values between 0-5V - there are 1024 steps. Watch my vide entitled: How to make a simple Arduino ohmmeter - you will learn how to get resistance values.

[@guha2487]

Thanks for your simple and clear explanation

[@AliehsPJ]

Great idea! Thanks for this helpful tutorial.

[@syedayman9322]

I did not yet get my answer? in order to preheat the sensor, do I need to use the resistor or only use straight 5v power. My datasheet said it needs to preheat for 24 hours, but it does not mention if I need to use the resistor or not, my values with out preheat are coming in like: 0 344 200 523 123 882 1023 0 50 122 The values are very unstable, but do you think it will be fixed after the pre heat?? I am a very frequent viewer of yours, I like all of your projects,A quick answer will be apreciated, thanks in advance

[@syedayman9322]

Syed Ayman Waiting for your reply

[@xosphere_1562]

three years no reply 😔😔

[@mashamustakim631]

Its amazing and helpful for the novice guys.

[@ElectronFunCom]

Masha Mustakim I'm glad you find my video helpful :) Thank you!

[@crimsontechyt]

Thanks so much, I couldn't find any other info on this :)

[@dinil21]

hey nice work man. keep it up and thanks for the lesson.

[@ElectronFunCom]

Dinil Divakaran I'm glad you like the video, thanks a lot!

[@MichaelWohlwend]

very instructive tutorial, thanks

[@Mudbloodprincess98]

Thanks for the great video! The resistor leads are a little hard to see, does it go from the ground rail to the same row as the B pins?

[@TurboDirectSA]

Nice Vid - great help thank alot!!

[@ElectronFunCom]

Chris Kambouris Thanks a lot for watching :)

[@McGavel1]

Excellent - thank you very much for sharing info! I'm trying to make this for my indoor garden because it's so much cheaper to make and I've just gotten into Arduino. Good luck - have fun.

[@ElectronFunCom]

I'm glad you like the video. Thank you for watching and commenting! Good luck with your project :)

[@McGavel1]

ElectronFun.com Ty - keep up the good work - peace.

[@syedayman9322]

It is a very good project

[@shantanu10496]

superb tutorial. very easy to understand. thank u so much !

[@ElectronFunCom]

+Shantanu Baji Thanks a lot for your kind words :)

[@abdallahegypt]

Hi, that's a great video, could you please tell me how you can make another one for detecting multi gases in the same time or if it's possible can you make another video , thanks in advance for you reply.

[@urvirelekar7189]

Thank you for the video. Sir, How do we calibrate the gas sensor to sense a specific compound? I read the datasheet it said we have to connect a resistor or potentiometer to measure a specific compound. How do I do that, sir?

[@ankeetmitra1122]

This was an amazing tutorial. Just wanted to know what is the alternative to heat shrink tube as I can't find any

[@NavJordaan]

i'm a little late so i dont think its helpful, but you can just wrap some tape around your exposed wires and it'll be fine

[@TahaCodes]

Thanks, the tutorial was great!

[@ElectronFunCom]

Thank you very much :)

[@RichardRauscher]

Good video. Thank you for making it.

[@ElectronFunCom]

Thank you :)

[@ronyjoseph7868]

hi, can it possible to print the data to lcd with this gas sensor arrangement instead of gas sensor module

[@maxlim15]

hi.. may I know which sensor can be use to detect n2. nitrogen.. I mean building a N2 supply inside a isolate small compartment. , would like to add in a sensor to detect leakage. Thank you

[@ElectronFunCom]

I'm not aware of a sensor from the MQ series, which could be used to detect nitrogen, sorry.

[@Socceregy]

Very cool. Thanks for sharing!

[@ElectronFunCom]

Thanks for watching and your nice comment.

[@scamper_van8470]

My thumbs up for the video quiet useful since i am missing only arduino and the sensor for my detector for hydrogen.

[@mattclark7941]

Hi love your videos, I'm in the middle of a project building a gasification unit to run a generator on woodgas, would you be able to do a video on how to use an Arduino with a car 02 sensor to control a rc servo adjusting the gas to air ratio?

[@sarfarznawaz]

thumbs up for u r demonstrations thanks.

[@ElectronFunCom]

+Sarfaraz Nawaz Thanks :)

[@francescomotterle8038]

Hi, nice video! I'm trying to do the same as you, but with the MQ-131, ozone gas sensor. I'm trying to understand: how have you found the value of the resistance to put on your board? For the MQ-131 sensor i need to preheat the sensor for almost a day, Someone says you have to change the resistance after the preheat to have a good measure. But I have seen you can change the value of sensitivity in the sketch, so How do I have to do? In any case thank you :)

[@ElectronFunCom]

+Francesco Motterle Thanks a lot! I took my resistor's value from the datasheet. However I checked your MQ-131 datasheet and it says "load resistance: variable" - it's pretty confusing, but you can use a potentiometer and adjust sensitivity. Preheating the sensor is advised by the datasheet - yours says: "over 24 hours", so it's a good idea to do that.

[@halakhaldoun]

When you choose serial monitor to view data in a new windor, are you be able to copy this data or not? Or a data logger shield should be used to export data needed?

[@ElectronFunCom]

Yes, you can select, copy and paste the text from the Serial Monitor window.

[@abdel-kerimmoctar9350]

Hello would the kl27z card work the same as your arduino card?

[@faizanthapur9845]

What do I do once I click the MQ-5 datasheet download link? When I clicked the link it just took me to a page with download links but I don't know which one is the datasheet for MQ-5

[@vishnuvardhan4093]

Thank you for ur awesome video. But i searched a lot for this video, it could be easy and reachable if you've used the title as 'Gas leakage detection'.❤️

[@zelra891]

this is an interesting video. I would recommend you to explain more like how the sensor works or why to connect wires like this. I mean, now I know how the sensor works with arduino, but I can't do it if I want to add a sensor to my project. take an example, we can get some analog outputs with this diagram, but what's the meaning of this value? how to convert the number to some standard numbers? This will be really helpful because if I want to do an air monitor project with this, I don't know how to define the number. LED lights up when it's 500, but what's the real number that matters in our life? In datasheet I see a relation between sensor resistance with ppm, but maybe a starter will never figure out. anyway, this is a great video. I have subscribed and wish you have more excellent videos :)

[@ElectronFunCom]

Zelra 仙賢戀軒 Hi, thanks for your comment, subscription and advice. I'm trying to make my videos not too long. Maybe I should have explained more details about the sensor.The values are something between 0 and 1023 and they come from Arduino analog to digital converter. If you want your readings in ppm units, you would need to calibrate your sensor against a known gas concentration (maybe this part of explanation should be included in the video).

[@edits_zyx]

Hello, I really liked the video and i want to ask you few things on this, can we have sensor, alarm speaker and simple power supply which makes compatible and sense the gas. can you pls describe.

[@ElectronFunCom]

Thank you! Yes, it is possible to have a gas sensor with a power supply or some kind of battery and a speaker, which would alarm you, if it sensed certain gas concentration. The easiest way to make something like this would be to replace the LED with a small speaker. I want to build a simple gas leakage detector in one of my next videos and use a speaker, or an LED bar graph or an LCD to show the results. I'm not able to tell you exactly when, because I have a "regular" job, which prevents me from making videos quicker and more frequently. I can see many people are interested in gas sensors, so this video will get higher priority.

[@mehrielyes6184]

Bravo, good work, i like your channel

[@ElectronFunCom]

Mehri Elyes Thanks a lot Mehri :)

[@Nasim_Mishuk]

awesome sir

[@Nada-lv6xv]

Hello, Thank you for the video. It's helpful !! I would like to know if the use of the resistors is necessary or not ? and what are the effects if i don't use them? thanks.

[@ElectronFunCom]

Nada Hi, thanks for your comment! The resistor is necessary according to the datasheet. I guess the readings would be completely inaccurate without the resistor.

[@rabiulislamabid750]

Excellent! This is so helpful. Would you please help me more measuring the value in ppm unit rather than 0 to 1023?

[@FoXaSsaSsin97]

sir i use mq2 sensor module that has 4 pins . how do i connect them to the arduino ? do i need to modify the sensor like taking out some resistors and capacitor on the module ?

[@FoXaSsaSsin97]

can you use the mq-7 sensor ? that have an accuray close to 100 % ?

[@ElectronFunCom]

I would not expect 100% accuracy when it comes to any of the MQ sensors.

[@SinhueENES]

Hi. We read the datasheet of Mq-135 sensor, which sense for multiple gases in arduino. However we have a problem because our laptop only read one column, as you shown in this video. We do not know what kind of gas we are reading (how we do that?), and furthermore, we want read all gases in several columns. is possible to do this? thank so much in advance.

[@ElectronFunCom]

+Sinhué Haro Corzo You might want to use Sandbox Electronics piece of code to "calibrate" the sensor and get a separate reading for each gas: forum.arduino.cc/index.php?topic=181780.0. I haven't put too much time into it yet, but I know some people get pretty decent results.

[@kanpeng1133]

man its really useful thx

[@ElectronFunCom]

Thanks a lot for watching and your comment :)

[@nishanklakkakula9699]

do we need to preheat the coil for getting perfect reading?..

[@ElectronFunCom]

nishank lakkakula The datasheet says you need to do it, it makes the readings more accurate.

[@nathannguyen6905]

What size heat shrink tubing did you use? Thanks

[@syamilfuad5098]

may i know for testing purpose, how do i produce/get the other gases? which can be detected using MQ2 sensor

[@laithmohamed2236]

Thank you for answering ,,

[@ElectronFunCom]

laith mohamed No problem :)

[@jonathanquinn9512]

Hi, great video, I want to add in a 6v buzzer, what the best way to do so? I have never used this code before, thanks!

[@ElectronFunCom]

Hi, thanks! Arduino Uno is rated for 5V, so it would be better to use a 5V buzzer. If you deliver voltage to the buzzer it will turn on. If you want to change the tone, you could use Arduino "tone()" (arduino.cc/en/reference/tone).

[@josephdistefano1955]

Thank you so much, this works great.

[@ElectronFunCom]

+Tractor Guy1232 Cool, thanks for your comment :)

[@ikhsanrahman9703]

Hello, I wanna ask, how to make stable value that displayed in serial monitor? I always get much fluctuations

[@henriqueliska3448]

Hi, can i use this with the MQ131? it works in the same way?

[@richardcain452]

Nice video. Very clear. Thank you!

[@ElectronFunCom]

***** Thanks a lot for your kind words :)

[@bonetogol]

Hello man... I need put the sensor in a tube to detect the the H2S Through the tube area... Do You know if it's possible? I can measure the gas volume pass by the tube?

[@abingeorge7750]

its really awesome project...

[@ElectronFunCom]

Thank you very much :)

[@christopherschadt9895]

Wow! There are a ton of questions/answers for this video. I tried to search throught them with some keywords, however I could not find answers I was looking for about cost and about lower detection limit and accuracy in the low range of measurements. Looking to build something similar but it would have to detect and readout values for CH4 way below the LEL at around the 10ppm range in order to be useful for my project. Sorry if this question is repetitive from those asked/answered before.

[@nnejimichael9701]

Can I use it to detect content of methane in biogas

[@saravanans937]

Hi sir, This is awesome. Will you please upload a video about blood glucose monitoring using acetone sensor (mq 138)?

[@zouaouisaifeddine5250]

hello , can i use this code to connect this sensor to TTGO WATCH MODULE GPS GSM ?

[@johnjoseph2064]

thanks for the video man

[@ElectronFunCom]

Thanks for the comment :D

[@DhirubhaisNayak]

How did u connect those 6 wires to mq2 please tell me

[@mohibullahbukhari7461]

Great video,can i have just readings without led?

[@alfiez3783]

hello...can we use the gas sensor to determine tea aroma?

[@ElectronFunCom]

It might be possible, but to tell you the truth I haven't heard about it before. I googled something like zinc oxide nanorod sensing element, but have no idea how it works and if it's possible to use it with Arduino.

[@MrYeshwanthln]

Nice video ! Thanks much .

[@ElectronFunCom]

Thanks a lot for your comment :)

[@clip8327]

When hook up MQ-2 with 5V onboard pin, the voltage drop to 4.86V Is it better to use the external very smooth 5V regulator ?

[@ElectronFunCom]

It's better to use an external power supply, because the MQ-2 consumes up to 160mA, while Arduino Uno can deliver 200mA maximum. If you connect something more than just the sensor, you can burn out your Arduino.

[@azmaljamal]

may i ask. what type of power source do you use in making this project?.

[@ElectronFunCom]

+Azmal Jamal Sure, I used a cheap adjustable bench power supply, nothing fancy.

[@skydronecordoba2023]

Can this sensor be mounted on a drone to sense CH4 gas? Is the indication reliable?

[@12bjab]

what sensor can be used to detect gases like acetone ,isoprene etc?

[@alexpiaro9449]

that a really good work,its nice and please can i get a manual or instruction on how i can calibrate both MQ7 and MQ8 on Arduino uno board for detecting CO and H2

[@ElectronFunCom]

Thanks a lot :) Unfortunately the software calibration I showed in the video entitled "How to use gas sensors with Arduino" works only with the MQ-2.

[@mohamadnuh2188]

May I know what imperial unit that u use for sensor detect?

[@abrehamwolde787]

does this program display numerical values on LCD???

[@user-ri6uu9zj4d]

Do you have a video MQ 9 it? It will work as long as the voltage of 5V?

[@ElectronFunCom]

I don't have a video about an MQ-9, sorry. Yes it will work with 5V.

[@carmenflorea4294]

Hello ! Your video is very helpful. I want to try this project by myself and i want to make it portable. I am new in this field and i need some suggestions. Can i use a battery instead of the source? I also have to upload the code on Arduino, how can i do that? Thank you !

[@jpikspiks2067]

I am using an mq4 methane sensor. Does it have the same drive circuit to power up the sensor?

[@ElectronFunCom]

+Jpiks piks Yes, you can use it in exactly the same way.

[@dinosongoku]

keep doing bro

[@zbert12]

Hi! Can I just supply the sensor with the 5V pin from the arduino?

[@ElectronFunCom]

Yes, you could do that, but you would get quite close to the Arduino's current limit. Be careful not to fry the pin or the whole Arduino.

[@blubblub9836]

Can it detect ethylene gases? And able it to detect even in 2meters far

[@bouyoucefamine8303]

Hi, thank you very much for this very well explained video. What do you think about using the MQ2 for a consumer product ? Do you think it is sturdy and reliable enough for commercial use ? Thank you

[@ElectronFunCom]

+Amine Ben Hi, after playing with these sensors for a while I wouldn't recommend them for commercial purposes. They are good for learning and experimenting, but that's it. In my opinion they are not reliable enough for a commercial project.

[@bouyoucefamine8303]

Thank you for your answer. Would you recommend any gas/smoke sensor for commercial purposes ?

[@ElectronFunCom]

+Amine Ben Sorry, I don't have any commercial experience.

[@aizamariesambo4481]

Sir may i ask, for instance i am going to use 3 MQ-2 gas sensor. What will be the connections? and how about the power source?

[@ElectronFunCom]

+Aiza Marie Sambo You would need to connect each sensor to a separate Arduino's analog input. Each sensor should have it's own resistor connected to ground. The rest of the connections would remain untouched. The code should be updated to read from 3 different analog inputs. When it comes to the power supply - for 3 sensors you would need at least 500mA at 5V.

[@SwissAmbush]

Hey man. Awesome project! If I am trying to make a reliable diy smoke alarm which sensors will I need? The MQ-7 for CO and MQ-2 for everything else? Thanks!

[@ElectronFunCom]

Thanks a lot Jim! You could use the MQ-2 alone as a smoke detector. However, I wouldn't use these sensors in my home smoke detectors. They are nice when you want to learn how to use Arduino with them, but their reliability isn't very good.

[@malikmalik33959]

I like your project but how much or value does the gas sensor"s limit

[@ajaykumar-xm6tv]

Brother Where can I get the code for Mq135 gas sensor, so as to use it for measuring CO2 level

[@samsonmasebinu5734]

Can I convert the readings to percentage and regulate the logging time interval. Also added like three more sensor and find their percentage composition in the biogas.I want to use it to log biogas composition from my digester.

[@ElectronFunCom]

You can easily adjust the logging time interval and add more sensors - each one should use a separate Arduino analog pin. The most difficult part would be the conversion of the readings into percentage.

[@ramilebful]

hello in my country i found mq-7 can i use it as this example ?

[@ElectronFunCom]

Yes, it should work with this circuit, but MQ-7 is sensitive to carbon monoxide.

[@diegogalafassi3694]

Hi, do you know if there are CO2 detectors available that would be able to capture a signal of human exhale?

[@vatsalgupta8033]

how to find what threshold to keep, like u kept 500?

[@nayakakshay5735]

Can we use any supply or is it necessary to have just 5 volt

[@dk_noobmaster46]

do you know the sensor to measure the Oxygen (O2) gas?? btw this video really helpful for my experiment project. thank you

[@ElectronFunCom]

Sorry for replying so late. Unfortunately I couldn't find an O2 sensor. At least from the MQ series.

[@govindsah5317]

If I will add buzzer then what are the changes I have to do in your code sir...

[@rayleneabella5752]

Does this work on mq4 methane gas sensor?

[@akhileshsharma5702]

Superb video ...I am a new comer to innovation and gonna start my first experiment with this. Thanks for so detail and simple explaination :)

[@ElectronFunCom]

I'm glad you like the video, thanks for the comment and good luck with your experiments. If you have any questions while experimenting, feel free to ask :)

[@akhileshsharma5702]

ElectronFun.com Thnks! Pal... Will do the same definitely :)

[@akhileshsharma5702]

Dear pal , CAn we also assemble it into a single device? How to do so? Regards

[@ElectronFunCom]

Akhilesh Sharma What do you mean by single device? Do you want to build a simple Arduino using only necessary parts and use it with the sensor?

[@akhileshsharma5702]

ElectronFun.com yes kind off.... I was trying to use it at my home after making it... is computer connection necessary each time?? and can bread board be replaced by something? Regards

[@shuvashisbanerjeeshuvo4545]

Thank you very very much .

[@ElectronFunCom]

No problem, thanks for watching :)

[@roly630]

Is it possible to use the HS 134 in the same way ?

[@ElectronFunCom]

+Ro Ly Not really - as far as I can see it uses 4V for heating the sensor, while the MQ-2 and MQ-5 use 5V.

[@shalmanurhida413]

should we have to calibrate this sensor before using that?? thx

[@vasudevang04]

which sensor can be used to detect ethylene gas

[@rizwankamleen1691]

Can i use it in flame detector circuit? Until which temperature it can easily work? If i use it near to fire will it works?

[@ElectronFunCom]

Rizwan Kamleen Unfortunately you can't use it in a flame detector circuit. The MQ-2 can operate only up to 50 degrees C, see here: sandboxelectronics.com/?product=mq-2-smokelpgco-gas-sensor-module.

[@edwinchukwudi2939]

can i really use MQ-5 LPG Gas Sensor to measure Gas pressure

[@seafoodmu6001]

can i use the telaire t6613 sensor with a USB cable to get the readings?

[@ElectronFunCom]

I haven't used anything similar, no idea.

[@Guyc00l]

why not connect it to arduino 5v power supply and why after 2 - 3 minutes the readings go low? is the sensor only supposed to work for 2-3 min and then shutdown or the other way around to heat up?

[@realblackfox]

Hello. Do you need a fan to direct the ambient gas if this sensor sits inside an enclosure box?

[@ElectronFunCom]

***** Why do you want to install the sensor in a box?

[@realblackfox]

ElectronFun.com For aesthetic purpose. I want to design a box that can detects gas leakage and smoke. Do I just leave a small hole opening for the sensor to detect the gas? Does the airflow is adequate enough for the sensors to detect the gas? Or do I put a mini fan to circulate the air into the box chamber?

[@ElectronFunCom]

***** I haven't tested anything like that, but I guess a hole in the box might be not enough and a fan might affect your readings, but it's only my theory. It's always a good idea to try out new ideas.