"New Single Coil, Pulse Induction Metal Detector"

Created: August 16, 2017
Latest Update: March 31, 2018.

Warning: I Do Not Recommend this project for the "Beginner",
It definately Requires Good Soldering Skills and at least a basic working
knowledge of electronics is Needed.

However, Occassionally I have some Pre-Assembled, Calibrated and Tested PCB's.
Usually there is Little or no additional charge for these Pre-Assembled Boards,
But they still require you to connect up the Controls, Meter, Piezo, etc and
put it into a suitable case.
But this might help some Less Experienced Persons.

I do not supply Schematics or other info, Unless you buy the parts from me.

**A Kit of parts Is Available from me.
Except for the PCB and coils, these parts are supplied at my Landed Cost.

When Purchasing this detector Kit from me,
I will also send you a 8.5" X 14" Printed Schematic,
as well as a 4" x 6" color Overlay Picture.

Email Me for the Current Prices.
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This unit is Quite Stable.

NOTE: Before Testing the Completed Unit
Wash the board to Remove All Flux Residue, AS IT WILL NOT WORK CORRECTLY IF YOU DON'T!

I Recommend using a Current Regulated Power Supply Just for "INITIAL TESTING" testing of this PCB.
So NOW I supply this Simple Circuit to limit this Current for Initial Testing,
thus preventing any damage to the parts.
When Voltage tests are Complete and OK, Remove this Current limit Circuit.

Good Soldering is a Must!
NOTE: It is Important to use a Good Soldering Iron, Rated at about 25 to 35 Watts
and having a Small Clean Tip.

NOTE: However, If you build this PI project and have problems,
I will offer you as much assistance as possible in e-mails,
Even to the extent of Free Repairs, Not Including Postage Charges,
and Assuming the actual Circuit board has Not been Damaged beyond Repair.

A Note about the Battery:
I Do Not recommend using a Lithium Ion Battery on this detector,
because most are rated at 10.8 to 12.6 Volts.
When the battery goes below 11.5 Volts the detector will Lose Proper Voltage Regulation
And become Unstable.

I do Recommend using 10 NiMh Batteries will provide Better Power, because they Maintain
a Constant 12 Volt supply or use a 12 Volt Sealed Lead Acid Battery. (Gell Cell)

Note: This Detector was Not designed as a Gold Detector.
However It Will detect larger Gold Nuggets with a suitable coil.
But if your expecting to detect Tiny Nuggets or Flakes of Gold, FORGET IT!

I can supply this "Piezo Transducer" that works Excellent on this unit.

I can now supply these "Female RCA Jacks" that work good if you use a 3 ft
Audio cable with the RCA Plugs on each end for connecting the Coil to the PCB.
Sorry, I do not supply these cables, but they are commonly available.

I can also Supply this 3.5mm, Stereo Headphone Jack.

It has a Built in Switch to turn off the Piezo, When the headset is plugged in.

I can Now Supply this "GOOD" Vu Meter

The Pots I supply have Aluminum Shafts.
So if wanted they can be easily cut to a more suitable length with a Hack Saw
to fit these "New Knobs" I have acquired at a GOOD PRICE."

Mounting Position for Soldering the Surface Mount REG1117A Regulator.

"Click on the Titles below to open them"
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Radial Coils I Make for sale!

Here is A Very Simple Coil that Will Work,
At least for testing purposes.

Here is a Pretty Good Coil that is reasonably easy to make.
Decades ago this style of coil was used for AM Antennas in some Old Tube Type Radios.

How to Accurately Pinpoint objects with large PI coils.
This can be especially useful when digging up an object.
And Always keep checking both the hole and the earth you dug out to make sure you can find the object.

REVISED Feb 24, 2015....More Coil Winding Info

Article on "How PI Detectors work".

IMPORTANT NOTE
The only claims I will make as to the sensitivity of this Detector is:
The one I made for myself does detect a Canadian Quarter (made of
Nickel) at 10 Inches in Air and at 10 inches in the soil in my yard.
Also an American Quarter (Zinc I Believe) at a distance of 8 inches in Air

Additionally, If built correctly: With an 8" Coil, This Metal detector should detect a
"Pop Can" at an "Minimum Distance" of 15 Inches.
AND it could get to 25 Inches or More, depending on the Coil & Meter you use.

However there are too many Variables in Coil Construction, as well as
materials, shapes, sizes and soil conditions to try to predict exactially
what your detector will do under various conditions.

ADDITIONALLY, Remember This:
THE MOST IMPORTANT THING WITH ANY METAL DETECTOR, IS THE OPERATORS
"ABILITIES", "SKILLS" AND "PATIENTS" in using it PROPERLY!

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Chemelec