BME 680 low humidity values

[MassaRoddel]

I am getting very low humidity values from the sensor. I use the source code from github to control the sensor and do the calculations. Pressure and temperature values seem to be ok.

Here is an example:

pressure: 998,7mbar

temperature: 41.88C (the pcb is warm)

humidity: 14.88%

What could be the problem?

[FAE_CA1]

Hi,

Thanks for your inquiry.

Please get a humidity meter as a reference to check the humidity value that you got from BME680.

Thanks.

[MassaRoddel]

Humidity is about 51%.

I attached the self test results. Test was made about 30 minutes after system was running.

Also, I wonder why we get gas resistance up to 6MOhm. According to the documentation I would expect much less. We have two prototypes which show the same results. Communication is SPI @4MHz.

[Alain1]

Given the "high" temperature I wouldn't be suprised that the RH is really that low at 42°C.

The RH does change a lot depending on the temperature and the 42°C is used to calculate it.

If you need the RH, I expect that it's needed to lower the PCB temperature quite a lot and then do a recalculation to the room temperature.

[MassaRoddel · Accepted solution]

Thank you, that makes sense. If the gas resistance values are also ok then everything is fine. I was worried that we might have broken the sensors during soldering. Our application is not about air quality.