mq2 sensor.

[cissy.christine]

hi there.

ca someone please suggest a project that uses MQ2 sensor and arduino. thanks

 

[Reloadron]

Flammable gas sensor, what sort of project did you have in mind? I couldn't find much well defined output data for the sensor. I guess you could sniff air to a point of explosive atmosphere concentration with a little calibration.

Ron

 

[cissy.christine]

thanks for the response
we are thinking of breathalyzer using mq2 instead of mq3. we follow one circuit hat we saw online but we didnt get the same result.

 

[Reloadron]

Can you post the circuit?

Ron

 

[cissy.christine]

here's the link of the project's site that we followed.
https://www.danielandrade.net/2010/03/07/building-an-breathalyzer-with-mq-3-and-arduino/

we used the same schematic.

 

[Reloadron]

When I get home from work this evening I'll take a look at it. From what I saw they are just running an analog signal from the sensor into the uC analog in. They look at the signal level from the sensor and light the LEDs on DO lines accordingly. It should work for you? What is not working? You can also simulate the sensor signal using a 10K pot with one end to ground and the other end to +5 volts. Connect the pot wiper to the analog input pin of the uC.

Ron

 

[Reloadron]

I dug up an Arduino Duemilanove that was given to me sometime back. I ran the Arduino software and loaded the code from the link. I ran the chip simulating the input using a pot to feed an analog input into the analog input (pin 0) and things worked. What exact problems are you having?

Ron

 

[cissy.christine]

our problem is, the sensor didnt respond on our tests. we used smoke and alcohol for it to detect but still no response. we are thinking that maybe its because we use mq2 instead of mq3. hmmm. in your opinion, is it because we used another sensor instead of the sensor used in there project?

 

[Reloadron]

The MQ-2 should detect alcohol gas per the data sheet. I would start by measuring the analog voltage from the sensor to the uC analog input pin. As alcohol laden gas is introduced to the sensor the analog voltage out should increase, you should see a change at that point.

Ron

 

[Mikebits]

It looks like the sensor resistance is different between the MQ2 and MQ3.
One is for gas, the other for alcohol.
https://www.pololu.com/file/download/MQ2.pdf?file_id=0J309
https://www.electro-tech-online.com/custompdfs/2011/08/MQ-3.pdf

 

[cissy.christine]

we tried using alcohol . the sensor's voltage had a very very small change . then when we try it again, the voltage remains the same.

 

[Reloadron]

we tried using alcohol . the sensor's voltage had a very very small change . then when we try it again, the voltage remains the same.

If the sensor is not showing you any change that would explain why the project isn't working. While the sensor you are using does mention alcohol it may not work for this application as was mentioned. I can tell you this much, if the sensor out voltage isn't changing then the project will not do anything.

If you have a 10 K pot you could place it across a 5 volt supply and connect the wiper of the pot to pin 0 (analog in of uC) vary the pot and watch the analog in voltage change. The LED string should follow the change.

Ron

Ron

 

[cissy.christine]

If you have a 10 K pot you could place it across a 5 volt supply and connect the wiper of the pot to pin 0 (analog in of uC) vary the pot and watch the analog in voltage change. The LED string should follow the change.

Ron

Ron

weeew~ too technical for me. but we will try that. thanks for the respond . we'll keep you update .