[mircemk] is quite a wizard when it comes to using coils of wires in projects, especially when their application is within easy-to-build metal detectors. There are all kinds of ways to send signals ...

If you think of a metal detector, you’re probably thinking of a fairly simple device with a big coil and a piercing whine coming from a tinny speaker. [mircemk] has built a more modern adaptation.

THE TECHNOLOGY’S EFFICACY. YEAH. WHEN IT COMES TO KEEPING SCHOOLS SAFE, SECURITY EXPERTS TELL ME A METAL DETECTOR ALONE IS NOT ENOUGH TO PREVENT WEAPONS FROM GETTING INSIDE. ACCORDING TO OFFICIALS ...

The working principle of this cheap and easy to build metal detector circuit consists in mixing two equal frequencies which causes a low-frequency interference. When one of the oscillators become ...