Additional Info on My Metal Detector

Latest Revisions: July 30/2008



Here is some info and pictures of my
Completed unit.
Also Some info on Other Metal Detectors







Some Notes about My Detector:


1) I am only using a Single Coil on this one as It works best for my purpose!


2) Therefore, I have omitted Q2, as it isn't necessary in my unit.


3) I also omitted C23 and C24 as in my unit as it worked a little better
without them. These Capacitors create a frequency compensation which is
sometimes necessary.


4) In my "FIRST Prototype", I used a Pizo Element in place of the speaker,
mainly to reduce the overall size. In order to make this to work
effectively I had to incorporate a small transformer to step up the output
drive voltage.
You will see this small transformer in one or more of the pictures below.
** That transformer is No Longer Needed.
I have changed the circuit to work really good with the Pizo I supply now,
and without the transformer.


5) My Coils are all fitted with standard RCA type phono Plugs. They are
small and make it easy to change from one coil to the other. In my unit I
have found very little or no re-adjustment is necessary when coils are
changed and this can be done without turning the unit off.








Closeups of my unit



My units front panal
 


A close up of my assembled/mounted PCB



Another closeups of my PCB



Closeups of the PCB, copper side



Extreme Closeups of mounting of the "REG1117A"




Below are pictures of my completed coils.



1) "Close up of 8 inch coil".



2) "Close up of 8 inch coil".



3) "Close up of 8 inch coil".





1) "Close up of 3.5 inch coil".



2) "Close up of 3 1/2 inch coil".



3) "Close up of 3 1/2 inch coil".



4) "Close up of 3 1/2 inch coil".



One of many new coils, I'm considering using



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I have been able to Borrow a "Radio Shack"
"Discovery 2000 Metal Detector" For testing purposes.
Both the Detection in "All Metal Mode" and "Auto Notch Mode", gave very
simular results. I believe this is a Inductive Balance type and the Tested
Operating Frequency was 6,565 Hz.

My Test Results on this unit:

  •  A 1/2 Gram Gold Nugget. NOT DETECTABLE

  •  It detects a Canadian Quarter at 4 Inches.

  •  My one ounce Pure Gold bar at 6 Inches.

  •  Large Mans Gold Ring at 5 1/2 Inches.

  •  Side of a Car (Steel Body) at 23 Inches.

  •  Side of a Truck (Aluminum Body) at 12 Inches.

  •  Canadian Copper Penny at 3 1/2 Inches.

  •  12 Inch Square Copper Plate at 14 Inches

    


    ENJOY
    

    

    
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