After wanting to go treasure hunting but not being able to find their own metal detector, Arduino enthusiast "Dzl" decided to make their own and based it around an Arduino. A metal detector is quite simple to make - you create a large coil which is connected to a simple oscillator circuit which generates the pulses that alter in frequency whenever metal is near the coil. In this case the Arduino measures the pulses and controls a speaker to alert the user of a possible find.
This would be a fun project to share with children or others, and ideal for something different to do at the beach or park. For complete instructions on how to make your own, visit the project page. And for more, we're on twitter and Google+, so follow us for news and product updates as well.