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    BHI160 and BMM150 accuracy definition for SW API what does this mean

    Member

    BHI160 and BMM150 accuracy definition for SW API what does this mean

    Can someone please explain the meaning of the "accuracy" value given back in the SW API's for most sensor measurements for BHI160 and BMM150. I undertstand the algorithms train themselves to try and minimise errors and maximise accuracy.

    We are currently reseting the whole chip complex and re'initialising between taking measurements. I think this is probably wrong; meaning we would always start  sampling from a low accuracy point. How long does sensor complex have to be running to reach a state of best accuracy?

     

    I have seen a definition was posted here for one of the other sensors.

    https://community.bosch-sensortec.com/t5/Question-and-answers/What-does-the-IAQ-accuracy-mean-in-BSE...

    Is this defined anywhere for the BHI160 & BMM150?

    3 REPLIES 3
    Member

    Re: BHI160 and BMM150 accuracy definition for SW API what does this mean

    Just been dumping the accuracy value for the  VS_ID_ACCELEROMETER_WAKEUP, VS_ID_GYROSCOPE_WAKEUP, VS_ID_MAGNETOMETER_WAKEUP.

    When I start sampling I see them all start off 0 - unreliable; after a short period maybe a (second/minutes) I see the magnetometer has progressed to accuracy 3; yet the accelerometer and gyros still say 0. Can I expect these also to at some point start reporting high accuracy and not just unreliable?

     

    Community Moderator
    Community Moderator

    Re: BHI160 and BMM150 accuracy definition for SW API what does this mean

    Hi owain-incus,

    BHI160 follows the Android sensor type and naming conventions. This question is already answered here:
    https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/BHI160-plus-BMM150-calibration-procedure...
    Highlighted
    Member

    Re: BHI160 and BMM150 accuracy definition for SW API what does this mean

    Hi,

    Thanks for links; trying to digest these at the moment.

    So some background. We are working on a tracking/movement analysis product. We analyse how people move.

    Typical use case being someone goes for a 30 minute+ run. We log at 100Hz and use virtual sensors for accelerometer, Gyroscope, magnetometer, linear acceleration and orientation. We power-up the sensors at the start of the run and down at the end. We need high accuracy data for our further analysis.

    So are you saying this is the wrong way to use the device?
    Are BHI160 calibrators running all the time the device is on; irrespectful if we have enabled or disabled the virtual sensor?
    Is the fact we are power cycling the sensor complex screwing us?

    If we are powering the device up and down (Actually removing power and reloading FW each cycle); do we need to somehow save/initialisise the configuration?

    As said I can see magnetometer starting off un-reliable; but progresses to reliable; but I have not yet seen Gyro or Accel reporting anything but unreliable?

    Regards,

    Owain

     

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