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    BME680 BSEC Samping Rate

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    New Poster

    BME680 BSEC Samping Rate

    Hi,

    I am planning to use a BME680 for a desk based "info terminal" which should also show some air quality information. Currently, I am using the BSEC library and everything is fine.However, I've noticed that there are only two sampling rates BSEC_SAMPLE_RATE_LP and BSEC_SAMPLE_RATE_ULP with 3s and 300s sampling time, respectively. Is it possible to use other sampling rates, like 30s or 60s?

    My device will run only when I am at work, so at max 8 to 9 hours each day. During my tests I also noticed that the IAQ accuracy only goes up to 1 after ~200s (for LP mode; 20mins for ULP mode - this is mentioned in the data sheet). WIll the BME680 remember historical low and highs, so it will achieve higher IAQ accuracy values? Otherwise,  my plan to use it on my work desk as an air quality monitor will be useless, I guess.

    Thanks alot,

    Matt

    4 REPLIES 4
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    Community Moderator

    Re: BME680 BSEC Samping Rate


    @Mosquitsch wrote:

    However, I've noticed that there are only two sampling rates BSEC_SAMPLE_RATE_LP and BSEC_SAMPLE_RATE_ULP with 3s and 300s sampling time, respectively. Is it possible to use other sampling rates, like 30s or 60s


    I believe it is technically possible to reach ~60s sampling rate by using the ULP+ feature of BSEC, but it is strongly recommended to use one of the official LP or ULP modes, as BSEC was characterized and will perform optimally in these specific modes.


    @Mosquitsch wrote:

    My device will run only when I am at work, so at max 8 to 9 hours each day. During my tests I also noticed that the IAQ accuracy only goes up to 1 after ~200s (for LP mode; 20mins for ULP mode - this is mentioned in the data sheet). WIll the BME680 remember historical low and highs, so it will achieve higher IAQ accuracy values?


    BSEC will run a calibration process in background, therefore it would be recommend to run it continuously (even overnight) for ideally peformance. Alternatively, it is possible to backup and restore what is called a 'state' string from BSEC that will (among others) also include calibration information. Therefore if some non-volatile memory is available in your design, you could potentially back-up this state at the end of the day, then restore it back before the beginning of the next day.

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    New Poster

    Re: BME680 BSEC Samping Rate

    Thank you!

    My device is an ESP32. So, if I am not mistaken, the "esp32DeepSleep" example in the github repository can be used, to see how to dump, load and set states from/to the BME680, correct?

    Community Moderator

    Re: BME680 BSEC Samping Rate

    The 'esp32DeepSleep' example seems to highlight the deep sleep feature, but I believe that in this example the state is only stored in RAM and will be lost if the board is power-cycled. Maybe the 'basic_config_state' could help, but that example uses the EEPROM library for the ESP8266, therefore may need to be customized too.

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    New Poster

    Re: BME680 BSEC Samping Rate

    Thanks alot, that helps! 👍

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