I've searched to a massive amounts of blog posts, tuts, instructables. But all the project seem to be based of eachother.
I read that the MQ2 gas sensor is capable of detecting ppm of ethane/alcohol and hydrogen. (and more ofcourse)
But the only posts I see is being as a smoke detector that triggers something.
I just want to have data on how much ppm of alcohol and hydrogen.
Is there somebody with correct info on this and how to get this data out with a correct library.
I dont think these Gas sensors can tell you in isolation, how much Hydrogen and how much alcohol is in the air as seperate mesurements.
These sensors are sensitive to multiple gases at the same time, so I dont see how you could use it to measure only hydrogen for instance unless you were sure there were none of the other gases its sensitive to present.
In addition to sensing many different gases, the MQ sensors are not quantitative.
The sensitivity drifts and so it would have to be recalibrated using known gas standards frequently.
Start by determining your requirements, and how much you are willing to spend, then search for better sensors. They won't be cheap.
For a really interesting application using MQ sensors, check out the Electronic Nose project by Michael Madsen. http://www.maskau.dk/electronic-nose
It is off line, but archived versions of the web site are available on the Wayback Machine.