Go Down

Topic: MQ Gas sensors (Read 1 time) previous topic - next topic


I have purchased A Few MQ-Sensors: 135,2,4,5,6,7

Which you can view the datasheets http://playground.arduino.cc/Main/MQGasSensors#.UyC70PldXTo.

I do not understand how I am to set the sensitivity based on the readout of the devices.
Lets take MQ-2 (http://www.ebay.com/itm/400368453822) for example:

The problem I am having is I don't understand what the analog readout of the sensors is mean/representing.

Has any one worked with the MQ sensors and/or Any Ideas how I am suppose to use the readout data?


The MQ gas sensors are electro-chemical with a heater.
They are sensitive for a range of gasses, and if one of those gasses is in the detector, the conductivity between 'A' and 'B' gets better.
With a load resistor, the voltage over the load resistor changes, because of the better conductivity between 'A' and 'B'.
That's all.

You can try to calibrate them for a certain amount of gass, some do even calculations with the value to get a percentage. But that is just a wild guess, it is not accurate at all.


Connect sensor with a serial R (depending on sensor used: +/- 3k..30k,potmeter) - to get the analog readout near 500.
Leave sensor powed for 2 full days. (readout will drift, so R must  be changed)
Now (sensor powered for looooong time, in clean air) readout is near 500..
Study datasheet. to find how R_sensor changes for gas presence
Make your transfer function to convert change in readout to ppm.

Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131