Bosch Sensortec Community

    cancel
    Showing results for 
    Search instead for 
    Did you mean: 

    BME680: IAQ accuracy going from 3 o 1

    BME680: IAQ accuracy going from 3 o 1

    micha_pr
    Established Member

    Hello,

    using the BME680 as indoor sensor in office room I can see red marked IAQ accuracy

    18:57:52.693 -> 164814095, 24.24, 101317.00, 54.56, 731373.00, 38.85, 3, 24.18, 54.75, 32.37, 529.50, 0.56
    18:57:55.732 -> 164817096, 24.24, 101321.00, 54.58, 721204.00, 39.58, 3, 24.18, 54.77, 32.77, 531.06, 0.56
    18:57:58.729 -> 164820096, 24.25, 101319.00, 54.62, 729001.00, 36.84, 1, 24.19, 54.79, 31.31, 525.23, 0.55
    18:58:01.735 -> 164823096, 24.24, 101319.00, 54.63, 721976.00, 37.78, 1, 24.18, 54.84, 31.81, 527.22, 0.55
    18:58:04.726 -> 164826095, 24.25, 101317.00, 54.64, 712818.00, 42.12, 1, 24.19, 54.82, 34.12, 536.47, 0.57

    There was no reason for changing the accuracy to 1, I think...
    I understand that after a while in little changing environmental conditions the accuracy may fall down to value 2 until it can come back to value 3, but why to value 1?

    Value 1 will be there for at least 14 hours, as I can see.

    (BTW: it was taking 3 days until the IAQ accuracy was set to 3 - in office room. I know... stable environment ...)

    And - does it make sense to (auto-)save this config state (with value 1) and overwrite the existing state 3?
    Or can it help to save the old config state and reload it if there are no changes in environmental conditions?

    Thanks!

    Michael

    20 REPLIES 20

    BSTRobin
    Community Moderator
    Community Moderator

    Hello micha_pr,

    Default BSEC output values every 3 second. You should check your timestamp and ensure get_timestamp_us() function is correct. And try your test again.

    micha_pr
    Established Member

    Hi,

    do not understand.... every sensor is reporting values every 3 seconds as you can see in log, right?
    (there are two sensors in log)

    And every sensor have the same issue - that is going to accuracy "1" after some time and is not going back a long time again.

    This was the question... 😉

    Thanks!

    BSTRobin
    Community Moderator
    Community Moderator

    Hello micha_pr,

    If you use default BSEC config in you program, BSEC output data about every 3S.

    Yes, BSEC output data every 3 second in my following log, time stamp unit is nanoseconds.

    BME680 BSEC output.png

    If time stamp has wrong value, IAQ accuracy has posibillity to drop down.

    micha_pr
    Established Member

    Hi,

     

    ok, but do not understand what problem may be..

    I use "if (iaqSensor1.run()) ... "  and "if (iaqSensor2.run()).." and read the values.
    same code as in sample (basic_config_state_multi)

    You think it maybe better to use an own delay of 4 seconds as sample to read values?

    BSTRobin
    Community Moderator
    Community Moderator

    Hello micha_pr,

    IAQ accuracy indicator will notify the user when she/he should initiate a calibration process. Calibration is performed automatically in the background if the sensor is exposed to clean and polluted air for approximately 30 minutes each.

    BSEC IAQ accuracy.png

    From you log data, There was no big difference for IAQ value output. Do you have log data for more time?

    Icon--AD-black-48x48Icon--address-consumer-data-black-48x48Icon--appointment-black-48x48Icon--back-left-black-48x48Icon--calendar-black-48x48Icon--center-alignedIcon--Checkbox-checkIcon--clock-black-48x48Icon--close-black-48x48Icon--compare-black-48x48Icon--confirmation-black-48x48Icon--dealer-details-black-48x48Icon--delete-black-48x48Icon--delivery-black-48x48Icon--down-black-48x48Icon--download-black-48x48Ic-OverlayAlertIcon--externallink-black-48x48Icon-Filledforward-right_adjustedIcon--grid-view-black-48x48IC_gd_Check-Circle170821_Icons_Community170823_Bosch_Icons170823_Bosch_Icons170821_Icons_CommunityIC-logout170821_Icons_Community170825_Bosch_Icons170821_Icons_CommunityIC-shopping-cart2170821_Icons_CommunityIC-upIC_UserIcon--imageIcon--info-i-black-48x48Icon--left-alignedIcon--Less-minimize-black-48x48Icon-FilledIcon--List-Check-grennIcon--List-Check-blackIcon--List-Cross-blackIcon--list-view-mobile-black-48x48Icon--list-view-black-48x48Icon--More-Maximize-black-48x48Icon--my-product-black-48x48Icon--newsletter-black-48x48Icon--payment-black-48x48Icon--print-black-48x48Icon--promotion-black-48x48Icon--registration-black-48x48Icon--Reset-black-48x48Icon--right-alignedshare-circle1Icon--share-black-48x48Icon--shopping-bag-black-48x48Icon-shopping-cartIcon--start-play-black-48x48Icon--store-locator-black-48x48Ic-OverlayAlertIcon--summary-black-48x48tumblrIcon-FilledvineIc-OverlayAlertwhishlist