HCHO always zero

[bartolsthoorn]

Hi, I just received the SFA30 evaluation kit and I ran the code with a raspberry pi for about 8 hours.

Temperature and humidity is correct but HCHO only gives zero:

This is measured in a relatively new office building. At the same time, I also have the SGP30 sensor that shows readings above 100 ppb (the broad peaks are during night when I suspect ventilation is off).

I also have a BME680 sensor and it reports very high bVOCe, in the range of 5000 ppb.

Do you have any thoughts on which of the three scenarios could be happening?

1. The air is completely devoid of formaldehyde?
2. The software in this repo contains a bug?
3. Hardware failure (keeping in mind that the software does not report any error codes..)?

[bartolsthoorn]

Exactly the same happens with the Python software: https://github.com/Sensirion/python-shdlc-sfa3x