metal detector / металлоискатель

Homemade metal detector of induction type with Arduino. A metal detector emits electromagnetic waves that reflect metal. As an electromagnetic field sensor, we use the electromagnetic radiation tester 3120-En-00. The copper plate shields electromagnetic radiation from the metal detector. When metal gets into each field of the metal detector, the latter induced eddy currents that change the resonant frequency of the oscillating circuit. The frequency may increase or decrease depending on the magnetic propert