Pin Pointer-3, Metal Detector.

Created: "July 3, 2014"
Updated: "Mar 31, 2015"

Presently I am NOT Supplying any PCB's or kits for this Project.
I want to Get it working More to my Satisfaction.

This is a Very Sensitive Pin-Pointing Metal Detector and Quite Stable. I Have Never seen another pin-Pointer as Sensitive as this one.

I Found a Problem.
This Detector is Too Sensitive. It Does Not detect Dry "Black Sand" or "Dry Wood". Due to the High Frequency it Detects Moisture. It does Not detect a Dry Blade of Grass. But it EASILY Detects the Water in a Green Blade of Grass or Soil or anything that is not Perfectly DRY.

It is considerably Different from others designs I have seen before.

Depending on the Closeness to the metal, The LED Blinks from a Slow Flashing Rate to a Full On. And the Audio Sound goes from a Beep, Beep, Beep, to a Continuous squealing sound.

I show a few Possible Coils in a picture below.

NOTE:Larger Diameter Ferrites (8 to 12 mm or Larger) detect at a Greater Distance,
But do Not Pinpoint the location as Accurately. And Large Ferrites will Not Detect Smaller items as good. Smaller Diameter Ferrites (3 to 5 mm) detect at a Shorter Distance, But can Pinpoint the location Very Accurately. So the Choice is yours.

On My Assembled Prototype, Instead of a Conventional Pot for Fine Tuning, I used a 10 Turn, 5K Wire Wound Pot. These 10 turn pots are Not Cheap, But it is essential if you want GOOD SENSITIVITY. A 1K, 10 Turn pot would be even BETTER.

There are Pictures of Tiny Pieces of Gold Below and Distance of Detection for each. After Initial Panning, It can EASIlY detect Flakes of Gold in the remaining Black Sand. I can detect a Fine Chain Link at over 1 Cm with a 3mm Ferrite and the coils wound on it.

I can supply the PCB and/or the Parts on the PCB. I can Probably also supply a 0.25" x 1.5" Ferrite Rod..

Go Back to My "Projects Page"

The Schematic.

The Revised PCB.

Some Ferrite Coils I Made.

Picture of the Origional,Assembled PCB.

Picture of the Origional Prototype on Workbench.

Picture of my Assembled Working Pin Pointer.

Inside My Assemble Pinpointer-3.
        Note: I used a 10 Turn, 5K Wirewound Pot.
        This Gives a Very Accurate Calibration.

The Coil on This Pinpointer.

My Distance of Detection on many Small Pieces of Gold.

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