Helsinki has a strong underground heavy metal scene, so what better way to show it off than to have listeners literally unearth the local sounds themselves with converted metal detectors that play, naturally, Metal? [Steve Maher] built these modified detectors and handed them to a bunch of participants who went on exploratory walks around the city. The tracks from local bands changed as the user moved from one concealed metallic object to the other to create the experience of discovering the hidden soundscape of the land. 

Because there was no writeup on the hardware, we contacted [Steve] ourselves, and here is what we learned.  [Luis Alejandro Olarte] helped out on the build that uses a Teensy 3.2 with an audio shield to play tracks from an SD card. The beeps that would typically help you find metallic objects are fed to the Teensy and control the volume of the output audio. The Teensy then loops through a 45 minute track that is only audible when metal is detected. This allows the audience to establish a connection between the metal as well as the music.

The video has [Steve Maher] talking about the concept and some of the walks organised under the project as part of live Herring.

We think this is a great idea and can think of other variations on the theme. using color sensors to play tracks and sounds that allow individuals with colour blindness or complete ocular impairment to experience the shades in an auditory way? Red with loud music and sky-blue with the calm sound of a cool breeze. adding a bit of haptic feedback could take this idea in so numerous directions.

If you’d rather diy your own than modify one off the shelf, here’s an short article on building your own metal detector.