Build your own metal detector

Build your own metal detector article mentions a pretty interesting Diy Arduino based metal detector. The article starts with with an explanation of how most oscillator based metal detectors work. Most metal detectors uses a search coil that act as part of an oscillator circuit. When metal is put in proximity of the search coil the frequency of the oscillations change. This circuit design starts with an oscillator that produces a signal of about 160 kHz which is constantly measured by the Arduino.

When metal enters the coil it alters the frequency, which is immediately picked up by the Arduino. So in this design the traditional BFO approach is replaced with a microcontroller that can measure the frequency changes very accurately. When the ‘NULL SW.’ button is held the current frequency is stored and changes to it are are detected. This is an interesting idea to build a metal detector.

The source code is pretty compact. It promises that it works with search coil oscillator that has frequency in 20-200kHz range. This looks something that could be adapted to many different kind of search coils and maybe also for some other sensing applications.


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  2. Tomi Engdahl says:

    DIY Metal Detector

    Looking for a light project to teach young hackers some very basic electronics? Here’s a quick and easy weekend project, a simple metal detector!

    We all know 555 timers are very useful and pop up in a wide range of projects, but did you know a metal detector is one of them?

    If you don’t have a 555 on hand (tisk tisk) but still want to have some treasure hunting fun you can also build one based on an Arduino.

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  4. Tomi Engdahl says:

    EEVblog #714 – Metal Detector Reverse Engineering

    How does a metal detector work?
    Dave teardown and reverse engineers the circuit in a $17 Harbour Freight wand type metal detector, and also explains how to do basic reverse engineering of a PCB.

  5. Tomi Engdahl says:

    Simple but powerful metal detector

    It’s very simple to implement a valid metal detector with good performances. Very often people lose their metal objects at the beach or in the countryside. Coins, rings and necklaces disappear when they touch the ground. Starting from today this will no longer happen: thanks to this very useful device, it will be very easy to find buried items.


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