Build your own effective metal detector easily! This quick project uses two powerful Integrated Circuits: the NE555 Timer and the TL072 JFET Op-Amp. Our circuit utilizes the Beat Frequency Oscillator (BFO) principle. The NE555 provides a stable Reference Frequency. The Search Coil creates a second frequency that shifts when metal is nearby (due to inductance change). The TL072 then mixes and amplifies the difference between these two frequencies, generating the distinct detection tone. Key Compo