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Visitor II
May 26, 2021
Question

LIS2DW12 removing gravity

  • May 26, 2021
  • 2 replies
  • 1283 views

Hello, I have read in the "application notes" that :

The LIS2DW12 provides an embedded high-pass filtering capability to easily delete the DC component of the measured acceleration (pg 12) .

can you elaborate please? does that mean we can make so the readings will be without the 1g add-up, and (theoretically) in rest we will get x=0 y=0 z=0 ?

Thank you

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    2 replies

    ST Employee
    May 27, 2021

    Hi @Msaga.1​ ,

    yes, with the High Pass filter you can cut the continuous earth gravity and see only the vibrations you apply on the sensor.

    the readings in a rest state should be 0, but environmental noise will always keep that value different from 0.

    It is to be noted that stable accelerations are not detected when the HP filter is enabled.

    hope this clarifies the application note.

    Niccolò

    Msaga.1Author
    Visitor II
    May 31, 2021

    @niccolo.ruffini​  HI , thank you , can you reference me to how to disable the DC component?

    ST Employee
    May 31, 2021

    Hi @Msaga.1​ ,

    to disable the DC component, you need to enable the HP filter.

    this is done using the BW_FILT[1:0] bits and FDS bit in CTRL6 (25h) as stated in the datasheet on page 21.

    FDS = 1 for HP filter and you can choose the cut frequency through BW_FILT.

    hope this helps

    Niccolò

    Msaga.1Author
    Visitor II
    May 31, 2021

    Hi @niccolo.ruffini​  , thank you. But now I dont understand - any activation of the HP filter will disable the DC component? ie - if I activate the HP filter without choosing the cut frequency, is the DC component is disabled?

    and what do you mean by "choose the cut frequency".