One common tool used for detecting magnetic fields is a handheld compass. Should the compass needle/card deflect as it is moved into the proximity an object, then the object may be considered to produce a magnetic field.
Similarly, a magnet may be used to test for or ferrous metal. Should a magnet be attracted to or be deflected from an object, then the object may be considered to produce a magnetic field.
One of the latest additions to tools for detecting magnetic fields is the Magnetometer function Gemeco's free iNstall app for smartphones. It is recommended that such testing be performed prior to permanently mounting the fluxgate. When seeking an installation
location for a magnetic north seeking device such as a fluxgate compass, etc., it would be considered a best installation
practice to test the magnetic field strength in the intended location while all onboard electrical
devices are on (and cycling or switching if applicable).
, for instance, has not specified a maximum sensed magnetic field strength value, verifying the iNstall's app's magnetometer needle is in the green band (+/- 10 µT) would be a good starting point.
Note that there is no form of screening (Lead box, wire mesh etc . .) that can be installed around a compass sensor
to eliminate the effects of external deviating fields, in such cases where excessive deviation is encountered, relocation of the sensor
is the only option.