Not much as it clearly isn't a metal detector. You'll need a search coil to start with, not an off the shelf inductor.What do you think about this circiut
The simplest is nothing more than an oscillator used in conjunction with a pocket transistor radio - I forget what you tune the oscillator to beat with, but the oscillator tank coil is also the search coil - conductive objects interfere with its inductance and shift the oscillator. Heterodyne whistles indicate a winner.Not much as it clearly isn't a metal detector. You'll need a search coil to start with, not an off the shelf inductor.
Google-fu will yield you hundreds of circuits. I'd start with a very simple design.
This page is a good starting point. I'd build a frequency shift detector to start with. If you want to go farther, a pulse induction detector is considerably more capable.
There are two main designs, The Bfo type,
Radio projects hardly ever get offered to beginners these days - metal detector projects probably moved up a place.But to me this is another one of those things that an off the shelf professional model will in the end be cheaper. Especially when the OP says, "What do you think about this circiut and i can't quite understand."
Actually, there is a third kind, pulse induction ,shown in the link I posted way back towards the top this post.. It's more complex when built with logic but is more sensitive. It works similar to sonar in that it pulses the search loop and then "listens" for the induced field decay. Slower decay means something's there. I've been looking at adapting one of the designs to use a microcontroller to replace all the logic and timing generation. Could wind up being relatively simple. Gotta fix my scope first, though.There are two main designs, The Bfo type,
or the Induction Balanced...the easiest one is Induction balanced as it uses one detect coil.
Plenty of circuits here,
ATTiny's too.Some people code PICs to emulate the 555 timer.......................
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