digital compass modules

[joerg]

Am Mi  23. Januar 2008 schrieb Sébastien Lorquet:
> I'm not sure a magnetic sensor is useful when you have a GPS, because a GPS
> can give you a heading as soon as the measured velocity is not zero!
You get heading of *velocity vector*, NOT heading of *device*! So for Andras' 
intended use, this is worth nothing. It works only for objects like a car 
that supposedly are not able to move in a direction different to "straight 
forward". I even guess if you drive backwards with your car, the map on those 
navi-units will rotate top down.

j