We are right now working on the device which is using Bosch BME 680 sensor.
And the task is to get the eCO2 ppm values. However during our testing the ppm value never reach the value less then 500ppm.
Even when the sensor is working all the night outside.
We did not find any information regarding the range of the measurements of the eCO2 ppm value.
Is it somewhere specified ?
And is it possible to get the value less then 500ppm ?
Not sure about the specifics of a BME680 but I am seeing the same with my BME680 but also with other sensors (CCS811) - the minimum value CO2 value is always at 500ppm. Maybe this is a baseline value?
The CO2-equivalent output is derived from the static-IAQ. Here it looks like ~500ppm of eCO2 corresponds to ~25IAQ of sIAQ, or typical good air as considered by BSEC. Slightly lower values could be observed from time to time, if BSEC finds new cleaner air to recalibrate itself from.