I have just bought a breakout board with the MQ-2 from herehttp://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280615774635&ssPageName=STRK:MEWNX:IT
. I was wondering if you have made any progress. The code included is for standard reading of an analog port. Googling around, I think this is the best I found http://arduino.cc/forum/index.php/topic,55780.0.html
. However it's not exacltly about MQ-2. The MQ-2 datasheet is here http://english.hwsensor.com/ewebeditor/uploadfile/en/MQ-2.pdf
. The datasheet is not the most clear one to me.
Basicaly what we are looking for is Rs/Ro. Ro is constant and is the referance R at 1000ppm of H2. At this point Rs=Ro, so as long as we can calculate Rs at this point we will know Ro, too. But how do we calculate Rs at 1000ppm of H2? And how do we calculate Rs anyway? The analog read gets voltage for us, right?