Build Your Own Metal Detector Projects & Circuits

Electronic hobbyists usually get around to building their own metal detector. Metal detector circuits and the corresponding schematics can be very simple to quite complex. Of course, the more complex circuits will perform better, but a simple one can be quite effective. Listed are links to web sites to help the electronic hobbyist decide which project is right for them depending on skill level and need.

Types of Metal Detector Circuits

There are three major types of metal detector circuits. BFO, or Beat Frequency Oscillator circuits are the simplest to build. BFO metal detectors use tuned coils where one of them acts a search coil. When metal comes close to the search coil eddy currents are produced and changes the current flow. The circuit detects this change and is reproduced as a change in the output, either a meter or speaker.

Induction Balance metal detectors, or discriminators, uses two balanced coils within the search head. Phase response can be detected in such an arrangement and different metals discriminated.

Pulse induction metal detectors are lower frequency devices. An electronic pulse is created and sent through the coil and the decay of the pulse detected.

Electro Schematics

The Eletroschematics website has plans for a really nice BFO metal detector. It requires few parts and is easy to build and get working. The circuit is very stable and should provide many hours of metal detecting pleasure for such a low price.

Easy Treasure

Easytreasure site is another BFO project that works quite well. This metal detector is of a more traditional design and very simple to build. The parts are quite common and easily found in most electronics hobbyist's parts bin.

Gary's Pulse Induction Metal Detector

This pulse induction detector is more complex to build. The project takes a little longer to assemble but the results can be very rewarding. This is not a project for the beginner.

Electronic Projects

The Electronic Projects website offers a nice metal detector schematic that uses a super heterodyne design and two oscillators. The oscillators consist of a transistor and ceramic filter tuned against a Colpitt's oscillator. This is a metal detector project for the more advanced electronic hobbyist.

Geotech

The Geotech site provides links to an array of metal detector projects and schematics. There is even a project for building a coil winder.

Conclusion

One of the main components of a metal detector is the search coil. The coil must be of the correct inductance so that it is matched properly to the circuit. Stability is a huge factor. The coil should be built solid yet remain light weight.

It is very useful to have the right electronic test equipment to tune the detector circuit, but with a little ingenuity it is possible to build a quality detector with a few common electronic tools. Please follow all safety advice and be careful of hot soldering irons.

Sources: Personal Experience