[zaphod] had to research how a metal detector actually works. After reviewing the pros and cons of various approaches, the decision was made to go with a beat frequency oscillator (BFO) circuit.

A pulsed induction metal detector induces a current spike in its search coil, and times the decay of the resulting oscillation. The coil is part of a resonant circuit with a capacitor, and any ...

The present IP is a VCC Detector (VDT) circuit, which prevents the possibilities of causing Flash writing failure or internal operation failure by unstable supply voltage. It detects the voltage level ...