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    BME680 - unrealistic eCO2 Values

    BME680 - unrealistic eCO2 Values


    As described in

    we use an example application with a precompiled bsec library for data evaluation (BME680 sensor): 

    This time we test the BME680 sensor with a rasperry pi zero and the SEN-BME680 eval board (Joy-it) - so we can exclude hardware failures on our side (since the raspberry is used in many other I2C-Applications without any problems ....)

    Again, the measured eCO2 trendline contains unrealistic jumps and measurement results (eCO2):



    - Is it possible, that there is a bug in the bsec-library?
    - Is there a physical explanation for such unrealistic jumps in the trendline?
    - Maybe the firmware on the BME680 is buggy? Is an update available?

    Our customers expect somehow realistic eCO2 - values .... I know, it's just an estimation for CO2, and I may expect errors in the range of 100-200 ppm ....
    But jumps in the range of 600ppm for no reason? Or values in the range of 5000 ppm in a normal office room
    (I think I should be dead if the values are correct 😉 )?

    Any help would be great - Thanks in advance!

    Best regards,
    Bernhard Mathias

    7 REPLIES 7

    Thanks for the update. Based on raw data signals, this time I believe the output looks as expected. If we look at the raw resistance signal from the sensor, we can see an actual step response from the sensor to some event. I cannot from the data only determine the origin or amplitude of this event, but something has been detected by the BME680, and this event is thus translated in BSEC outputs as well 🤔



    Ok, let's assume there was an event - even though I'm not sure what happened because the sensor is located in our office room and the air ventilation in the room works well.... and the peak is really high ...
    I will try to do some further tests.....
    Best regards!

    It could be as simple as someone coming back from a cigarette break getting close to the sensor, strong perfume smell, or simply farting.

    The source of air pollution might not have been CO2, but the sensor definitely detected something in the air.