Has anyone else used the compass modules from Seeed?
We are seeing serious non-linearities in the output of the devices. Even in raw vector mode, the X and Y components don’t seem to make sense.
In order to reduce the effect of hard-iron offsets we’ve tried multiple, physical locations away from all ferrous materials. The only ferrous materials in our entire assembly are the crystal cover, the GPS module cover and the USB connector on the Cerb40. All of these are more than 25mm from the Honeywell sensor.
To deal with soft-iron factors we’ve settled on a look up table.
So the question! Has anyone else developed a calibration routine or strategy that we can use to linearise the output?
This is for a fixed installation and the calibration should ideally be of the table look-up variety (it can’t be done in service easily). I have no aversion to applying mathematical transformations either - plenty of CPU time available.
Thanks for the ideas!