[vonPongrac] stumbled upon this handy guide, a free eBook on 50 555 Circuits, which contains many cool project ideas, including a simple metal detector ... one based on an Arduino.

A new Instructables page has been created to make an eco-friendly DIY metal detector using an Arduino Mega just been combined with a 3.2 inch TFT LCD touchscreen to provide a fantastic readout ...

Here's how to throw together a DIY polygraph machine with nothing but an Arduino, some wire, and some tin foil.