The heart of this diy metal detector circuit is the CS209A IC. The metal detector is built with one 100µH coil that has 40 mm in diameter and is made of 50 turns/0.4 mm wire. CS209A has one oscillator ...

Posted in handhelds hacks Tagged diy metal detector, instructables, Metal Detecting, metal detector ← Making QR Codes In Google Docs CD-ROM POV Clock → ...

By using tech made popular in the early 1900s, anyone with a 3V battery, metal shavings, and electrical wiring can easily build a coherer energy detector.

A metal detector used to be an entirely analogue instrument, an oscillator whose frequency changed with the inductance of its sense coil when a piece of metal approached.