I want to use the BME688 sensor in a sauna to monitor the air quality and CO2 concentration.
The main aim is to know when the CO2 concentration gets too high and when I should bring fresh air into the room.
The BME688 is rated to work up to 85degC so I placed the sensor inside the sauna itself.
Outside the sauna I have another CO2 sensor, rated 60degC only, with a small airpump that bring air from the sauna and acts as a reference.
To simulate people in the sauna, I use a CO2 cannister from which I release some gas from time to time.
Right now the CO2 equivalent I am measuring with the BME688 seems totally off and very much influenced by the temperature and humidity. I do not see any correlation with the actual CO2 level that I am measuring with my other sensor.
I add some graphs of some measurements I have been doing.
I also have a BME688 evaluation kit and I tried to use the BME AI software to train an algorithm to detect CO2 from different sample set I recorded.
Unfortunately the gas estimate I was measuring was stuck at 33% and barely not changing, no matter what is going on in the sauna.
My questions are:
- How sensitive to temperature and humidity is the BME688 sensor?
- Can we measure pure CO2 with this sensor? Or does the CO2 equivalent is calculated from human breath only?
- Is this sensor useable at all for my use case?
I am using the BSEC library version 22.214.171.124 and use lower power mode (LP) for the sample rate.
Solved! Go to Solution.
Sorry for the delay reply.
1.The full range of the temperature sensor is 0~65 °. Can you test within this range?
2.BME688 sensor is some sensitive to temperature and humidity;
3.The sensor can test CO2 content in the air, not limited to human breath.
4. We cann't understand that the reference CO2 value has been maintained at 500 for a long time. Can you explain it? In the figure, are the reference CO2 and the CO2 output from BME688 measured at the same time?