This app measures the magnetic field strength using the magnetic sensor that is built into your device.
The natural magnetic field strength in nature is about 50μT (or 500mG, 1μT = 10mG), if there is any metal in the area, the strength of the magnetic field should increase.
Usage is simple: open this app on your device, and move it around some metallic objects.
The accuracy depends entirely on the sensor in your device.
Note that the magnetic sensor is affected by electronic equipment (TV, PC, etc.) due to electromagnetic waves.
A leather case with a magnetic snap can cause unwanted results.
Also, this app cannot detect gold, silver and coins made by copper (or any other non ferromagnetic metal).

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