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Topic: MQ135 Air Quality Sensor issues (Read 1 time) previous topic - next topic


Hello there

I've bought this sensor, I've just used it, I've read online, it says 48 of preheat. I have just used it

and what I read is a negative voltage that fluctuates to postive voltage in mV. I noticed that this voltage increases

as smoke increases but it is not stable, it goes to negative and back to postive.

Anyone here used it ? what's wrong? I think the wiring is correct.



I just figured out that it was not connected to the 5V.. When I connected it, the output gave about 3.5V and then started to decrease. it is decreasing and it reached 2.93V now.

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