MFM3 pinpointer is a metal detector app with metal discrimination. When we put a metal object near to the coil the frequency changes and in this way the app detects the changes of the frequency and when there are changes it detects that there is a metal object nearby. This pinpointer is capable of distinguishing ferrous metals from non-ferrous metals.This app works with the help of a small circuit (you can find it below).  The circuit is fed from 3.5v to 5v.  The circuit is very small and is m