I do believe, that before you start working on metal detector you should read more about metal detectors and how they work.
I am not hold responsible for any damage that occurred during reproduction.
Step 1: Parts and materials
- 47 kΩ resistor
- two 2μ2 F capacitor
- 9 V battery, switch, battery cable and some wires
- 100 m of copper wire, 0,2 mm in diameter
- gaffer tape and wood glue
Instead of buzzer you can use 10 μF capacitor and speaker (8 Ω impendence).
- breadboard and wires
- pliers, tweezers, pliers for making holes
- soldering iron and soldering wire
- sharp knife, ruler, pencil and pair of compasses
- hot glue
Step 2: Schematics
Step 3: Coil
I made coils core from cardboard. Coil is made from lacquered copper wire which is 0,2 mm in diameter. I did 260 turns. Before soldering, you must clean up both ends of coil. You can do that with help of sandpaper.