[SOLVED] Output from mq-2 gas sensor and how to read concentration from mq-2 sensor

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alphonsjp

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Hi all..
I'm new to this group. As part of my project, I would like to know whether MQ-2 sensor can give mV output for lpg?
And I would also like to know how to read the ppm directly from sensor. I mean whether it is having any linear relationship between sensor output and concentration level.
Please help me.. Its really urgent..
 

The datasheet shows a sensor resistance versus concentration curve. This is relative resistance, the referred Rs can vary by a factor of 10 between sensor exemplars, and the relation is nonlinear, but following a Y = X^c characteristic, the points are on a straight line in log-log scale.

You can calculate output voltage versus concentration from this curve and check, if you need linearization for your application. In any case, a calibration óf individual sensors is required.
 
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    S.P.S

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Thank you so much sir. This is really helpful for me..
 

Dear Sir
Could you please explain why we need calibration of individual sensors? And I read in one of the papers like if a sensor is calibrated for 100% LEL of methane, then we need to calibrate sensor before it is used for lpg gas detection? I'm not getting the real meaning of this calibration.
 

Did you read the MQ-2 datsheet, particularly the Rs range specification?

Personally, I won't account MQ-2 or a similar SnO2 sensor as reliable LEL detector. Maybe a catalytic sensor (pellistor).

But any sensor needs invidual calibration and periodical recalibration for reliable operation.
 

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