jim coughed up some electrons that declared:


inductive loops eh... could you describe how they work please? - are
they DIY-able?

ta
Jim

Have a hunt around on google for metal detector circuits and try Elektor
magazine.

Alas you'll have to buy a subscription to actually read these, but:

http://www.elektor.com/magazines/200...or.57240.lynkx
http://www.elektor.com/magazines/200...or.55389.lynkx

There's a free one he

http://www.easytreasure.co.uk/bfo.htm

If you can whack a few transistors and/or DIL chips together, you can make
one, for very little money.