MQ-135 Calibration Question

Hi,

I used the library from this site SniffingTrinket sketch | Details | Hackaday.io. I followed the instructions on this page.

Do i need to calibrate the sensor again after I power it off for a time?
Or do I need to add the ZERO value on for the first time?

Best regards,

Christian

I have not tried to leave this kind of sensor rest for very long periods of times.
My experience is that it needs at least 10 minutes to stabilize after being off for some time. (a week)
It will then return same readings as previous week.

Hi!

Thank you for your answer.

Very strange, when I turn off my arduino/sensor and switch it on again (after 1 or 2 hours), I get different values from this sketch!

I did the burn-in for 24 hours, put it 1 hour outside and then added the resulting zero value to sketch and uploaded it.

Best regards,
Christian