If you’re of the “Goonies generation” like me, then hunting for buried treasure is definitely a desired pastime. And when hunting for precious metals, or even a few dropped coins, you need the assistance of science! The Treasure Finder, our latest installment of Weekend Projects, is a multi-day endeavor with potentially lucrative rewards. A true weekend project, this homemade metal detector will have you doing some light carpentry, etching your own PCB, and hooking up all the electronics necessary to detect nearby metals. Using the principle of heterodyning, two frequencies are mixed together (one from a reference coil, the other from the detector coil) to produce a new frequency, which has been calibrated to produce an audible beat (see video below). Changes in that beat produced by fluctuations in the detector coil’s magnetic field suggests a stash of buried loot. Whether you’re searching for currency (known as coin shooting) after a public event or simply combing the beach as a hobby, hunting for treasure can also become serious business. A recent success story is that of the Staffordshire Hoard in England which resulted in over 3,500 pieces from the Anglo-Saxon era being unearthed. Or you can put this project to the test by burying some loot in your yard and challenging your friends to find it!