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Wrong magnetometer measurements

ramirami
in Android

Hi,

I have two MMR Sensors and both are showing wrong magnetometer measurements with constant -0.002048 value in x and y and unreasonable values in z.
I'm using the MetaBase application in android.
I suspect there is a hardware problem but I'm not sure since it occurs in both sensors.
Tried to search for similar discussions but could not find.

I would appreciate your advice.

Comments

  • nekosnekos

    Maybe you need to calibrate your sensor

  • ramirami

    @nekos said:
    Maybe you need to calibrate your sensor

    Is it possible that the calibration is so out of tune that the sensors are saturated with a minus sign?
    And please consider that the sensors are new; meaning that they supposed to be calibrated..
    Thanks

  • LauraLaura

    Is it an MMR+?

  • ramirami

    @Laura said:
    Is it an MMR+?

    I'm not sure since I don't have access to the sensor right now.
    But it was surely not vibrating when I used it.
    Does this helps?

  • LauraLaura

    Basically, any magnet in the surroundings, the battery, the coin vibration motor, even just a nearby pieces of magnetized metal will affect the measurements of the magnetometer. Without additional information on your setup, I cannot comment on your magnetometer values.

  • ramirami

    @Laura said:
    Basically, any magnet in the surroundings, the battery, the coin vibration motor, even just a nearby pieces of magnetized metal will affect the measurements of the magnetometer. Without additional information on your setup, I cannot comment on your magnetometer values.

    Hi Laura,
    Its a standard MMR.

  • LauraLaura

    Thanks but there is still likely things affecting the magnet like your surroundings, the battery and so on. You can experiment in various ways and get back to us.

  • ramirami

    @Laura said:
    Thanks but there is still likely things affecting the magnet like your surroundings, the battery and so on. You can experiment in various ways and get back to us.

    We have conducted several experiments with **two **MMR sensors using the MetaBase application in android.
    The following setups were tested:

    • Several 100-150 meters walks with the MMR strapped to the leg in different routes.
    • Several "magnetometer calibration" tests where the sensor is rotated in all directions in a clean earth magnetic field surroundings (In open space, about two meters above the ground and far from metals sources)
    • Several tests indoors near computers and other sources of magnetic field disturbances.

    In all cases magnetometer measurements are providing constant -0.002048 value in x and y and unreasonable values in z as described in the first message.

    Thanks,
    Rami

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