(Jesse's Amazing Metal Detector)
This verry simple circuit will detect gold or metal or coins at a distance of approx 20cm – depending on the size of the object.
The circuit oscillates at approx 140khz and a harmonic of this frequency is detected by an AM radio.
Simply tune the until a squeal is detected when the search coil is placed near a metal object, the frequency of the circuit will change and this will be heard from the speaker.
The layout of the circuit is shown and the placement of the radio.
Read your schematic and put it on a bread board
Next you transfer the design from the bread board to the pc board with all the exact same components.
After putting it on the pc board I made a prototype outer design for the JAMD