Metal Detector

[locko]

Hi G-R-C

I had the same idea, so started with a non-pic project to learn how it works.
The net has several example circuits for BFO and pulse metal detectors.

http://www.rpi.edu/~bradfe/MD/MD.html
http://oldradiobuilder.com/MDET.html
http://www.talkingelectronics.com/pr...ectorMkII.html

I built the circuit from http://www.easytreasure.co.uk/bfo.htm - had good description.
It works but the feedback control is a pain and the depth detection sucks, best I could get was about 2" with a 5" coil in air. Note:You WILL need an Oscope for setting the coil frequency etc.

Due to the terrible depth detection, I have not persued this project any further with using a Pic, but with someone else having the same interest, I may have to start it back up again.

If you have access to PCB Wizard, attached is the circuit I made for the BFO.

Regards,

Paul

Edit: There is a Pic based metal detector called Gold Pic (search the net). You have to pay for the pre-programmed pic chip but I think you can find the circuit for free. I will see if I have anything saved for this and post it if I do.

Edit2: Here is the link http://home.global.co.za/~trh/gp301n.gif