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Topic: CONVERTING ANALOG OUT OF MQ-7 TO PPM (Read 2 times) previous topic - next topic

RIDDICK

hm
i never did it myself...

maybe this works fine:
hardware:
+5V(from arduino) -- pin A
GND(from arduino) -- ~10kOhm resistor -- pin B
it seems like the heating voltage affects the resistance between pin A and pin B...

software:
measure the voltages at pin B with an analog pin... http://arduino.cc/en/Reference/AnalogRead
regarding the LCD: http://arduino.cc/en/Reference/LiquidCrystal?from=Tutorial.LCDLibrary

interpretation of the readings:
u will need reference concentrations...
but be careful: CO is dangerous to humans and animals...
so u should possibly do it together with a teacher who smokes (cigarette smoke contains CO)... but: smoking is not necessarily healthy... :)
then u should c a change of voltage...
but then u wouldnt know how much CO it was... :-)
maybe u know a firefighter? they might have calibrated CO meters...
-Arne

vhenamae

thanks again.. i already have the conversion code and i was able to display it in lcd.but the main problem there is that i dont know if the reading is accurate. :) so same with your suggestion i used a cigarette. :) i will try another method

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