Compass Calibration

for the complete list of supported compas , please read the magnetometer page

Instalation

explain how to position the mag

Calibration

press the mag calibrate in the gui.

for the next 30 sec or so when the led is flashing

rotating the copter around all axes is what you have to do.

1. rotate 360 degree around yaw axis for x, y calibration
2. rotate 360 degree around pitch axis for y z calibration
3. rotate 360 degree around roll for x z calibration

http://www.multiwii.com/forum/viewtopic.php?f=8&t=1387&p=10658