Music is a nominally audio experience, but whether you’re at a large rock concert, listening to live music at a restaurant, or even scrolling through Spotify on your phone, what you see can be an important part of the experience. VU (volume unit) meters are one way to add to your listening fun at home, and Koji Gardiner designed his own take on such a setup with the Audiobox XL system, featuring Spotify album art integration.
At its core, this device is a 16x16 pixel LED matrix controlled by an ESP32 board. Output frequencies and sound levels are measured with an I2S MEMS microphone breakout, and translated into graphics shown behind a black acrylic diffuser. An internal grid separates each pixel.
What makes this mechanical setup really interesting is that the grid is actually situated on a rack-and-pinion gear assembly, controlled by a servo motor. This allows it to move closer to sharpen the pixels, or further away to create a softer effect.
Audiobox XL pulls album art from Spotify, and scales it down for display on a 16x16 matrix. The results are pixelated, but largely recognizable if you know what you’re looking for. The system also uses the actual album art to generate a color palette for the VU meter visualizations, producing a nicely themed visual counterpart to enhance your listening experience.
Lots more information on this setup is found on Gardiner’s Audibox XL project GitHub page — definitely worth a look if you’re considering a similar project!