This application is useful for detecting metallic objects, it is also useful for detecting hidden electrical cables due to the magnetic field that they generate during use.
The magnitude of Earth's magnetic field at its surface ranges from 25 to 65 μT, if when opening the application the magnetic field is outside this range, the blink calibration symbol will be activated and it will require you to calibrate the sensor. To calibrate the sensor see the help.
How to measure the magnetic field of an object?
1.- Check that the calibration symbol is off,
2.- Approach the object to the smartphone sensor and
3.- press the start button to measure the magnetic field,
4.- press the stop button to finish the measurement.
If you want to make another measurement press the reset button to clear the previous data and repeat the above procedure.

How to calibrate the magnetic field sensor?
1.- Move the smartphone in a figure 8 path.
2.- Check that the calibration symbol has turned off, if not repeat step 1 until the calibration symbol turns off. See the figure below.

The measurements accuracy depends entirely on your magnetic field sensor. Note that it is affected by electronic equipment due to electromagnetic waves.
Main features:
1.- Sound alarm.
2.- Visual alarm.
3.- Three measurement ranges.
4.- Four sample rates.