I recently bought the MQ2, MQ3, MQ5 and MQ9 sensors to measure the air quality.
As it is written in the documentation of the sensors, you cannot read the exact gas concentration.
This would require calibration with the right equipment.
But just for the fun, I would like to derive the gas concentrations via linear interpolation from the graphs in the datasheets (R0/Rs and ppm).
To do that I need two the x and y coordinates of two points on the graphs. Is this data available? If yes, would it be possible to get that for the four sensors I’ve bought?
you can read approximations on the graph, and you can put them into an array to implement linear interpolation. As you know, you cannot read the exact gas concentration but you can still have an approximate readout with all your gas sensors through this method.