How to make a metal detector?

Question

from these a solar powered calculator and a fm am radio

Answer 1

Do I have to use BOTH? If not, then simply use the AM/FM radio, remove one of the inductors in the tank circuit of the audio section and replace it with a big, air wound "search" coil on a stick - the change in inductance as the coil is swept over metal should change the pitch in the audio circuit.

If you have to use both, then power the batteries on the radio with the solar panel from the calculator... ;-)

Answer 2

and then you can make a computer out of old coke cans.

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