A free app for Android, by SimpleApps.

EMF (Electromagnetic Field) is the phenomenon caused by the presence of an electrical current and/or voltage in the environment. It is believed to be connected with the activity of living organisms. The level of the field is mostly near the surface of the earth and varies with time and location. It has been known to be stronger near metal objects and other electrical equipment. This app is used for detecting the presence of metals in the environment. With this app, you can easily detect just that with your mobile phone. 

[How to Use]

The app has an on/off button to enable the app to turn itself off when it is not in use. It also detects nearby metals and will let you know with the increase of the magnetic field. 

[Tips]

The field strength is in microtesla (µT). 1 µT = 10 mG.

*Phone must have a magnetic sensor for this to work