Beginners problem with mag sensor


I have a problem with mag sensor of the Drofly flight control. I tried several times to calibrate, but after calibration, the configuration menu still drifts to west and remains there.


and withtout calibration you have the same problem?

During the weekend I found the cause. I added a small piezo buzzer to indicate low battery, but it seems that it was to close to the center and disturbed the mag sensor, I removed the buzzer and the mag worked properly. Is anyone using a buzzer and the mag sensor without problems?

I have buzzer on my multirotor but it’s placed below with a wire.