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Poor Man's Metal Locator

It uses just five circuit components, is easy to build and works on the "beat balance" priciple for good sensitivity.

By Thomas Scarborough

This circuit represents a brand new genre of metal locator. Although it borrows from other kinds of locators/detectors, its basic principle of operation is new.

Click for larger image
No, it's not part of the circuit. This view inside the box shows the WHOLE circuit (with the exception of the coils, of course, and the tuning capacitor hidden under the PC board.)

And while this may seem to stretch one’s credulity, the performance matches that of a budget Induction Balance (IB) detector.

Build it – and you will see!

During testing, it detected an old English penny at 150mm (6") in air. However, I would only put my neck on the block for 125mm (5"), since a number of factors influence sensitivity. It roughly matches the performance of the now sadly misnamed Matchless Metal Locator (SILICON CHIP, June 2002), while using just one-fifth of the components.

This locator may therefore represent the writing on the wall for budget IB types and even puts paid to most of the advantages (the few remaining ones) of Beat Frequency Operation (BFO) detectors.

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