While using a metal detector to find valuable jewelry, and less valuable aluminum cans, can be interesting, the more accurately you can pinpoint the “treasure,” the easier it is. For excellent accuracy while maintaining a wide sensing field, Maker “TechKiwiGadgets” built a detector with not one, but four sets of sensing coils, all controlled using an Arduino Mega.

The device generates and senses a magnetic pulse from each set of coils, which is modified if there is a metallic object present. In search mode, the four signals are combined into a single display, and once an object is located, the four sensors can be shown in a split-screen. You can then dig where, and only where, it’s needed, minimizing work and your environmental impact!

Want to create your own? Check out TechKiwiGadgets’ Instructables page for more details and see a demo of it below!

Evan Kale is back with another hack. This time, the YouTuber decided to convert a weed wacker-like toy into a metal detector with the help of an Arduino Uno.

As Kale explains, the project is based on a Colpitts Oscillator, which combines an LC circuit with a transistor amplifier for feedback. The frequency of oscillation is somewhere in the 100KHz range, which cannot be heard by humans. Enter the Arduino. When the trigger is pressed, an Arduino program translates the oscillation into an audible tone that is played out of the speaker. When the oscillation exceeds a certain threshold, it also emits a celebratory light show because… why not?

Kale walks through his entire build—along with the science of it all and how it works—in the video below. The schematics can be found on Imgur.