CCO metal detector high sensivity

[metaldetector107]

hi all please any has the
CCO Metal Detector (high sensitivity) form
http://www.lulu.com/content/786843

thanks alot

[Fred]

Here:
https://www.geotech1.com/thuntings/s...ad.php?t=14433
This is the one.

[Qiaozhi]

Here:
https://www.geotech1.com/thuntings/s...ad.php?t=14433
This is the one.

He doesn't think that's the correct one, but it's bound to be based on the same idea. Here's another slightly different version:

[Fred]

Ok Qiaozhi,

I have to try this some day.Those detectors are so simples no "engineer" will ever build them, but i wonder how they really work.
Then with some special coil (PCB or the like) it could make a "letter shaped" detector, that would fit in a big envelope or look likle a plywood board
regards,
Fred.