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    BME680 CO2 and bVOC always zeros

    BME680 CO2 and bVOC always zeros

    New Poster


    I am unable to reproduce CO2 and bVOC values different from zero for BME680. I am using the BSEC and even when have high values for IAQ (500) at output_ready() always get 0.0 for both CO2 and bVOC. Can you help me to reproduce some meaningful values?

    7 REPLIES 7

    Occasional Contributor

    Hi Sir:

        You mean you want to get CO2 and bVOC value? You haven't still got CO2 and bVOC value although you could get IAQ value.

       If what I said was correct, maybe you should check function bme680_bsec_update_subscription(), check whether you opened the related virtual sensors.

      Hopefully, it helps you.


       Hi Sir,

    No you aren't correct - I read CO2 and bVOC but these values are always 0.0 (float). Do you know what shall I do to get some meaningful values?

    Occasional Contributor

    Hi Sir:

      Did you get IAQ value? I want to know whether not to open the related virtual sensors if you can get IAQ value.

      Do you share your source code? and let us know what plafrom you use? If needed, I would like to share my example code based on STM32 platform to you.

     Thank you.

       Hi Sir,

       Thank you, the virtual sensors for bVOC and CO2 were not enabled. I used the default settings from the BSEC basic IOT example. Now I get 500ppm for CO2 and 0.4 for bVOC.

       1. Can you tell me what аrе the boundary values for bVOC and CO2?

       2. Can you tell me at function bme680_bsec_process_data(), about static_iaq_accuracy, co2_accuracy and breath_voc_accuracy: shall I use corresponding value only when corresponding accuracy is 2 or 3. Are these accuracy values related to AQI accuracy?

       Thank you very much and wish you good weekend!