Placement of magnetometer in relation to speakers

asked 2016-07-26 10:41:30 -0500

Cerin gravatar image

How much does the presence of a speaker's magnet effect a magnetometer?

I'm trying to place a 9DOF IMU on a robot that has a pan/tilt head. The head contains a small speaker. I've read that the magnetometer needs to be calibrated to factor out static magnetic fields from surrounding electronics and magnets so it can accurately measure Earth's magnetic field.

How much will this small speaker's magnet effect it?

I want to place the IMU in the robot's base, since that would make wiring easier, but then it's relation to the speaker will be dynamic, so I won't be able to fully factor out the speaker's field through calibration. At some points, the IMU and speaker will be about 1" apart. Should I place the IMU on the head, so its relation to the speaker will be static, and therefore easier to factor out, even if that complicates wiring and interpretation of the IMU readings? Or am I overestimating the problem?

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I too would be interested in a response to this question. I am concerned about the magnetometer on the IMU picking up on the speakers magnetic field.

shoemakerlevy9 gravatar image shoemakerlevy9  ( 2017-11-28 15:54:32 -0500 )edit

In my experience, it would be a good idea to place the IMU as far as possible from the magnetic effects of the speaker. I have tried similar projects and the dynamic magnetic fields created have affected the true heading dynamically (could be 2-6 degrees off the true north), affecting localization methods significantly with heading drifts. Given that 4 years have passed, would you care to update on your findings/results? I am quite curious.

hashirzahir gravatar image hashirzahir  ( 2020-04-17 06:10:11 -0500 )edit