AirGradient Forum

Different PM readings with different firmware

#1

Hi, when I use the Arduino IDE to flash the 3.1.21 “snap” version of the firmware onto the unit, it gives higher PM readings than the over-the-air 3.1.21 firmware version. This is even if I make no adjustments to the version found in the Arduino library.

The PM 1, 2.5, and 10 readings surged when I used the Arduino “snap” version, with the 2.5 going from 0.0 indoors to 1-3 ug consistently. And the PM 0.3 count, while usually very low or none, consistently hover around 1,000 when using the “snap” version.

Are different firmware versions supposed to be able to change the PM readings like this? And are there differences in the version received over the air vs the one found in the Arduino library? Thank you.

#2

Hi @JMCair ,

Just wonder how’s your approach in comparing both version? do you have 2 monitor or test 1 at the time?

#3

Just 1 monitor, I switched it back and forth a couple times. The other readings seem unaffected, it’s just PM.

#4

Hi @JMCair ,

We’ll try to test this with 2 monitor running at the same time. Will give the update here.

#5

Thank you, also with the Arduino “snap” version, when it is starting up and says “press now for offline mode”, for a split second the text gets corrupted before it moves on and warms up, I don’t know if that’s an indication of something.

#6

In your case, is it consistent on every boot?

#7

Yes, every time. I also tested the 3.1.16 and the 3.1.10 versions in the Arduino library and they did the same thing. And it’s normal on the 3.1.21 OTA version. Perhaps Arduino is compiling or flashing it wrong?