Almost every speaker in a normal setup makes sound with a moving cone and coil. This build takes a very different route: the modulated electric arc creates the audio directly through thermal air expansion. Matthew Dunn pairs an Arduino with a high-voltage flyback transformer to do it, and the result audibly plays the Super Mario Bros theme as a chiptune melody. Music coming out of raw electricity is a genuinely striking result.
The circuit is refreshingly small: an Arduino, a flyback transformer with custom primary wire windings, a mosfet driver and a mosfet. A 100uF capacitor must sit close to the mosfet driver, and the maker shared a schematic while describing the whole thing as fairly minimal. The bench around it has a solderless breadboard on a baseplate, an electronics enclosure with an illuminated green light, plus a laptop, a benchtop power supply and an oscilloscope.
To strike the arc, a power source at the rear is switched on; turning the supply off extinguishes it. A wire held near the high-voltage terminal draws a continuous purple-blue arc across the gap, and long-nose pliers hold the electrode wire. At one point the pliers were pulled back to stretch the arc before being moved closer again. After further fine-tuning, the setup performed far better.
One open thread: the bass still distorts. Raising the current appeared to be the main remedy. Hotter, thicker plasma seems to hold steadier on low frequencies, and the maker believes hotter flames wander less, with that wandering behind the distortion. Whether the low end can be cleaned up completely remains an open question.
Project by Matthew Dunn. Watch it on their YouTube channel: