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Electronics All-in-One For Dummies, UK Edition by Doug Lowe, Dickon Ross

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Chapter 2

Unearthing Hidden Treasure with a Handy Metal Detector

In This Chapter

arrow Exploring the detector circuit

arrow Assembling the project

arrow Finding metal!

Everyone likes discovering something for nothing, whether it’s free sample music tracks to download from the Internet or treasure in your own home or garden. With a metal detector, you can scout out coins under the rug, nail heads covered by paint, keys in somebody’s pocket or many other hidden bits of metal.

In this project, we show you how to build a small, handheld metal detector that can detect certain kinds of metal – especially ferrous (iron-containing) metals – even if that metal is hidden under a little paint, plaster, sand or soil (but never water!). So here’s your chance to become known as your town’s Iron Man or Woman.

Uncovering the Big Picture: Project Overview

In this project, you use an integrated circuit (IC; check out Book III, Chapter 1 for details) that generates an alternating current (AC) signal that goes through a coil (also called an inductor, which we discuss in Book II, Chapter 4). Because metal objects conduct electricity, you can induce a current in those objects. When the coil in the metal detector comes ...

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