We are developing a product and wanted to test multiple air quality sensors, this included the BME280. Overall there were 10 devices in various locations logging the sensor values every 6 seconds.
When looking at the data the BME680 eCO2 reading does not follow a similar trend to any of the other devices tested.
The BME680 was sampled using the BSEC library on Arduino with the sample rate set to BSEC_SAMPLE_RATE_LP with the code otherwise following the Arduino provided examples.
Are there any other steps to get accurate eCO2 or can anyone comment as to why we seem to see an inverse trend on the BME680's eCO2 compared to the other 3 sensors?
We started logging data shortly after initialisation however the tests were done over a two week period during which the iaqAccuracy changed between 1 and 3. The graphs are from the final day of the test which I would have expected as plenty of time to calibrate.
Even with an iaqAccuracy of 3 the BME680 seemed to report an increase in eCO2 readings when it was infact going down.