Minimalist Induction-Balance Metal Detector
A low-cost treasure hunter
Published in issue 325, October 2003
This design is arguably the simplest IB (induction balance) metal detector that could be built from off the shelf components. The IB method of metal detection has a good depth of penetration and discriminates well between ferrous and non-ferrous metals.Metal detectors are available commercially but their price tag is often prohibitive to youngsters and those just starting out with the treasure hunting hobby. This article proposes a metal detector that is fun to build at a very low investment. Carefully built and aligned, it will clearly pick up a tiny 15 mm dia. brass coin at 70 mm in air, or a 25 mm coin at 120 mm. It will not fail to pick these up vaguely at up to one quarter greater distance. The ability to locate coins buried in the soil are, of course, dependent on soil conditions, dry sand being the most favourable, and clay, the worst, ‘medium’ between the treasure and the search head.
Unfortunately a few mistakes have been made in the numbering of three ICs on PCB 020290-1. This affects the component overlay of the board (Figure 2).Position IC1 on the printed circuit board should be IC4 (LM317).Position IC2 on the printed circuit board should be IC1 (7555).Position IC4 on the printed circuit board should be IC2 (7555).
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Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.