Seems i need this to make it work =>
A direction that is measured in degrees relative to magnetic north.
readonly attribute double webkitCompassHeading
Direction values are measured in degrees starting at due north and continuing clockwise around the compass. Thus, north is 0 degrees, east is 90 degrees, south is 180 degrees, and so on. A negative value indicates an invalid direction.
Available in iOS 5.0 and later.
Unfortunatly i'm not (yet) on iOS 5 ... and i don't think this function will be integred in Construct 2.