Hi,
I'm still seeing weird behavior from the AR.Drone when it comes to magnetometer readings, and I was hoping someone could help me understand what I'm looking at.
I logged some magnetometer readings while the drone was on the ground, pointing approximately to the north. Then, I plotted the raw and scaled magnetometer readings. I would expect the 3D vectors described by the readings to point roughly in the same direction, but instead, they look like this:
(The green vectors are the scaled values, red are raw. I scaled both datasets to be visible in the same chart, and flipped the scaled values' Y axis because I think I saw the Paparazzi code do that.)
The Z axis seems to have a much larger multiplier than the X and Y axes. I have to admit I don't understand how this is supposed to work. The calibration process seems pretty ad-hoc - it observes the measured values and then fits them to a range based on the min/max values it saw during the calibration... Right?
Anyway, from my reading of the AK8975C datasheet I don't get the impression that the Z axis should be scaled so differently from the other two axes. So I'm probably missing something, but I'm not sure what. Does this look normal to anyone?
Thanks,
Ori