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Wrong Magnetometer Data

ilius_faisalilius_faisal
in General

Hello,
We are using MetaMotionR+ for our research and taking accelerometer, gyroscope, and magnetometer data. However, We found that our magnetometer data is not proper from any sensor although we have 6. the sample data -
elapsed (s) x-axis (T) y-axis (T) z-axis (T)
0 -0.002048 -0.002048 0.000059438
0.039 -0.002048 -0.002048 0.000059438
0.08 -0.002048 -0.002048 0.000059062
0.122 -0.002048 -0.002048 0.000059062
0.161 -0.002048 -0.002048 0.000058687
0.202 -0.002048 -0.002048 0.000058687
0.242 -0.002048 -0.002048 0.000059813
0.283 -0.002048 -0.002048 0.000059062
0.322 -0.002048 -0.002048 0.000059875

We are getting some value from the z-axis but no change in x and y. We are using the Metabase app for taking the data and we did not modify anything. Could you please help me with this problem
Thanks

Comments

  • LauraLaura

    Hey Illius,

    Can you share mag data from three sensors (one from your defective unit) to see the difference between them.

    Now please note that MMR+ do come with a warning notice that the vibration motor has a magnet that may severely alter the magnetometer data. If you remove the vibrator motor, it will likely resolve your problem.

    This is documented and discussed in another thread in the forum as well.

  • ilius_faisalilius_faisal

    Hello Laura,
    Thanks for your reply. Actually all our six sensors are showing the same behavior. I am attaching simultaneous data from two different boards below.
    And if it is because of the vibration motor then why it is only affecting only x and y-axis data, not the z-axis.
    Lastly, could you please tell me how to remove the vibration motor from MMR+ board.
    Thanks

  • ramirami

    Hi,
    I'm experiencing exactly the same problem with two standard MMR sensors without vibration motor.
    https://mbientlab.com/community/discussion/3348/wrong-magnetometer-measurements#latest

  • liranshliransh

    Hi,

    I m experiencing the exact same problem:
    magnetometer Z has a vital value, but magnetometers X,Y are completely frozen!

    please help us to solve it. we can't use the MMR device without the 3 axis magnetometer.

    thanks,
    Liran

  • dwaterworthdwaterworth
    edited November 2020

    Hi,

    We're seeing the same thing with multiple sensors. The z-axis changes, the other two are stuck at -002048

    We replaced a sensor and it exhibited the exact same issue. We've ensured there are no sources of magnetism in the immediate location. In particular, the magnetometer in iPhones works fine when used in immediate proximity to the MMR. We're not using the motor - is this a permanent magnet motor? I.e. will it potentially impact the magnetomer even when not in use? If so, are there instructions on how to remove?

  • LauraLaura
    edited December 2020

    Again if you have a MMR+, the coin vibrator motor is a magnet and will give you erroneous magnetometer data. This is well documented on our product page and tutorials.

    For maximum performance, the battery should be as far away from the board and the vibration motor should be removed (if possible).

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