SparkFun Micro Magnetometer - MMC5983MA (Qwiic)

Sensors IMU & Motion
1

I’m using the SparkFun Micro Magnetometer - MMC5983MA to know the heading of a flying object. The reverse side of the MMC5983MA has the Y-axis along the longer side of the magnetometer and the X-axis along the shorter side of the magnetometer (Z-axis is normal to both). I have a couple of questions:

  1. Do these X and Y axes need to be precisely positioned along the X and Y axes of the frame of reference of the flying object respectivelly?? Or it’s irrelevant as long as software takes care of the difference in axis alignment??
  2. Do I still need a gyro+accelerometer or the magnetometer is enough??
    Thanks for any feedback.
    AA
2

  1. No, but the axis correction must be known and applied.

  2. A magnetometer is not enough to determine heading, if the magnetometer Z-axis is not always perpendicular to the Earth’s surface. Use 3D tilt compensation instead. The accelerometer determines “down”.

1 Like
3

Don’t know if I understand you, do you mean that both magnetometer and gyro+accelerometer are necessary??

4

To rephrase:

A magnetometer is enough to determine heading ONLY if the Z axis is always perpendicular to the Earth’s surface.

If the Z axis is not perpendicular to the Earth’s surface, tilt correction is required to determine heading.

Added: all magnetometers must be calibrated in their final mounting place, before they can be used as compasses.