Originally Posted by Jäger
If it works like a real compass, it is going to be more sensitive to masses of nearby metal (like a motorcycle - and why we swing the compasses on vessels), nearby electronic fields from electric motors, wiring, etc.
How sensitive I have no idea.
True, though since the display doesn't have to be in the same place as the sensor, you could hang the compass in a more plastic-y area.
Someone really needs to invent/discover shielding for magnetism.