So I am looking at building a methane and propane detector. I am planning to use the MQ-5 series detector. I read the date sheet and notice that methane and propane detection varies with humidity and temperature. The data sheet are not very well written and I was wondering if anyone know how methane and propane varies as humidity and temperature changes.
So if anyone has an equation that I can use to correct my reading as humidity and temperature changes that would be great or if you have a bunch of data points I can plot my own graph and get an equation from the graph.
Also please let me know if what I am doing is correct in terms of reading data values:
-Put a resistive load across Vout(A OR B depending on which one i choose)
-introduce the gas you want to measure at it’s hazardous level (methane or propane)
-read ADC and use that value as the base value for gas detection.
I also notice in the data sheet that the most of the data is given interms Rs/Ro (Resistance of sensor/Resistance @ 1000ppm H2). Do I have to actually calculate Ro at 1000ppm H2?
I figured out that from reading the MQ-4 data sheet that:
Rs= Resistance of sensor
Vrl=Voltage across my load (voltage across Vout pin i am using)
Rl= resistance of my load
Thus if I know Rs I can use the log graph to directly calculate the concentration of methane or propane please correct me i am wrong.