Mq136 and 137 coding problem


I trying to read values ammonia from mq137 and hydrogen sulphide mq136. I am not able to read ppm values . Can anyone help out with the code to get exact ppm values. Because now I am getting analog values. When reading from sensor.value(a0).

Because now I am getting analog values.

From what?

"Analog pin 0" is NOT a sufficient answer.

I suggest to read this page to understand how they work - then it depends what you have. just the component (then read the datasheet on how to build a correct circuit and influence of external factors on the value you will get) or if you have a breakout board with electronic on board. In that case you need to get the details from the vendor on how they tweak the output (is that digital, is that analog) and if the board has been already calibrated (and for which conditions).

alternately you need to calibrate it yourself. expose the sensor to known conditions of ppm concentration and see what the output is.