Raspberry Pi, is luftdaten.py accurate?

Hi, finally got my Raspberry Pi environ+ running outside today and uploading data, but what I found strange is that when I see the console, the temperature reported is much lower, then actual temperature. When I look at the luftdaten.py file → enviroplus-python/luftdaten.py at master · pimoroni/enviroplus-python · GitHub

The temperature that’s being reported is comp_temp and comp_temp = raw_temp - ((cpu_temp - raw_temp) / comp_factor)

comp_temp ends up showing up as around -7

but when I look at the direct temperature from BMP, it’s closer to 3C, while my WeatherFlow Tempest (about 30 feet above), is saying it’s closer to 0C.

Should I continue to use the luftdaten.py from the enviroplus github, or is there a different version of it I should be using?

The luftdaten.py code was developed by Pimoroni and not by Sensor.Community. We can’t really provide any information about it (or send me an enviro+ for me to test it :-).

Have you checked among the issues ? Issues · pimoroni/enviroplus-python · GitHub

Don’t forget that the BMP probably measures the temperature in the case and not outside.

Yes, now that I did more research, this problem seems to be more common then I realized, basically a lot of it has to do with what case you use to host your Raspberry Pi and Enviro+ sensor and how “physically” close your sensor is to the Raspberry Pi as the heat generated from just running the Raspberry Pi can have a significant effect on the readings, I’m going to have to play around before in modding the python code that uploads the data. Thanks for your response and more tinkering to do on my end.

HI Richard,
I’ve just Hacked the Pimoroni Enviro+ code to get it to work on an outdoor sensor. I didn’t use the Pimoroni board, I just mounted my sensors on wires away from the Pi, so removed the CPU Temperature compensation part, I did something like this:

Line 64 existing: comp_temp = raw_temp - ((cpu_temp - raw_temp) / comp_factor)
Replace with -
Line 64 new: comp_temp = raw_temp

Happy to share my code if you think it would be useful.
I’m now trying to figure out how to get better calibration on a PMS7003.
Drew

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