Calibrating Digital Compasses
I'm a fan of solid state flight instruments so I could not resist purchasing a digital compass that I saw in Halfords the other day. Ordinary ones don't work in my cars due to the interference of so many magnetic sources. How would this perform?
Out of the box it was completely useless - spinning wildy in all directions. But calibrated, it suddenly acquired an ability to track direction.
The funny thing is how you calibrate it. You press a button then turn through 360 degrees. Somehow it sorts itself out during this procedure. Question is - How does it do it?