There is a number of so-called Metal Detectors out there in the market.
This is often irritating since the phone's magnetic sensor reacts on
magnetism rather than on metals. Some metals, however, carry a magnetic
field, such as a pair of scissors or a screw driver.
Gold and silver do not assume magnetism in that an application like this
is not capable of detecting treasures.
However, the Android magnetic sensor, if incorporated, is well capable of detecting
objects, such as loudspeakers, cell phones, refridgerators and anything that contains
magnetism.
Not all Android phones and tablets employ the same magnetic hardware sensor, in that
sensitivity and accuracy may vary by manufacturer. Some devices do not provide a
magnetic sensor at all.
The application computes the total magnetic field, TMF, magnitude from XYZ components by squaring:
TMF = Sqrt(X² + Y² + Z²) [µTesla]
You can find your local TMF and finer components with the help of
http://www.ngdc.noaa.gov/geomag-web/#igrfwmm
and compare it with the value provided by your phone's magnetic sensor.
My phone, a Sharp IS03, is in good agreement with ±5µTesla measured indoors.
After all, in any case, this application is considered a fun application and must not be used
in critical situations.
A few field tests resulted in positive detection of magnetized objects, such as pipes,
drum cans, scoops, fences, etc. However, what is the purpose of scanning objects that
can be seen and touched? A real-world test should involve detection of objects buried
underground or in a wall.
Anyway, please try it yourself. If it won't work for you it will at least guide you
to the location of the magnetic sensor in your phone -- if there is one.
Further enhancements could involve data logging, charts, GPS based caching... you name it.
Please appreciate that you may not use the images for your commercial or
ad-supported applications. The code is yours to play with at will.
Tap on the Menu button for Help.
Suggestions are always invited and welcome.
Download Link
This is often irritating since the phone's magnetic sensor reacts on
magnetism rather than on metals. Some metals, however, carry a magnetic
field, such as a pair of scissors or a screw driver.
Gold and silver do not assume magnetism in that an application like this
is not capable of detecting treasures.
However, the Android magnetic sensor, if incorporated, is well capable of detecting
objects, such as loudspeakers, cell phones, refridgerators and anything that contains
magnetism.
Not all Android phones and tablets employ the same magnetic hardware sensor, in that
sensitivity and accuracy may vary by manufacturer. Some devices do not provide a
magnetic sensor at all.
The application computes the total magnetic field, TMF, magnitude from XYZ components by squaring:
TMF = Sqrt(X² + Y² + Z²) [µTesla]
You can find your local TMF and finer components with the help of
http://www.ngdc.noaa.gov/geomag-web/#igrfwmm
and compare it with the value provided by your phone's magnetic sensor.
My phone, a Sharp IS03, is in good agreement with ±5µTesla measured indoors.
After all, in any case, this application is considered a fun application and must not be used
in critical situations.
A few field tests resulted in positive detection of magnetized objects, such as pipes,
drum cans, scoops, fences, etc. However, what is the purpose of scanning objects that
can be seen and touched? A real-world test should involve detection of objects buried
underground or in a wall.
Anyway, please try it yourself. If it won't work for you it will at least guide you
to the location of the magnetic sensor in your phone -- if there is one.
Further enhancements could involve data logging, charts, GPS based caching... you name it.
Please appreciate that you may not use the images for your commercial or
ad-supported applications. The code is yours to play with at will.
Tap on the Menu button for Help.
Suggestions are always invited and welcome.
Download Link
