The cheap module I received from China had no instruction manual or circuit diagram, so I had to do a lengthy ... Here is the basic schematic of the metal detector module. I borrowed it from the ...

The heart of this diy metal detector circuit is the CS209A IC. The metal detector is built with one 100µH coil that has 40 mm in diameter and is made of 50 turns/0.4 mm wire. CS209A has one oscillator ...