Hello:

Dinsmore Instrument Company http://dinsmoregroup.com/dico/ has been
making digital compass products based on switching Hall  technology for
some time.  They now have a compass module (1655) based on linear Hall
technology.  It has two Hall devices at a 90 degree separation and by
reading the two voltages you should be able to determine the direction
of magnetic north.  Has anyone already used a PIC (16CE674?) to do this?

For a little more information see my web page:
http://www.pacific.net/~brooke/Sensors.html#Hall
and in patent 5,157,841 look at figure 3 which shows the drum holding
the permanent magnet supported by two bearings as well as a sensor
mounted close by.

Thanks,

Brooke Clarke