Your smartphone or tablet is real metal detector with this application semi professional.
This tool allows the detection of metal using the magnetic sensor built into the phone.
Try, you'll be convinced!
In addition to the digital display of the detected magnetic fields, you can add a sound or vibration, depending on the signal strength
Usage is simple: Open the application on your device, and move, values of the magnetic field are constantly fluctuate.
/!\ Your device must have magnetic sensor /!\