Phyllotaxis: An audio-reactive LED display
An engineer built an audio-reactive LED matrix shaped like a phyllotaxis spiral, driven by custom PCBs, an STM32/ESP32, and Rust WebAssembly firmware.
read it It offers a satisfying build log detailing code, CAD modeling, and hardware challenges for a physical generative art project.
summary
The author designed an audio-reactive LED display using the golden ratio phyllotaxis pattern seen in nature. They used CadQuery and FreeCAD to create cellular structures, wrote custom shader-like code for microcontrollers, and later iterated to custom PCBs with an ESP32 running Rust and WebAssembly. The final installation allows users to upload custom lighting patterns via a local web interface.
key points
- The point cloud is generated by spacing linear points on a radial line and rotating each by an increasing multiple of the golden ratio.
- Transitioning from 3D printed frames to 5-fold symmetric PCBs introduced major hand-soldering hurdles for the Neopixel LEDs.
- The final iteration runs an ESP32 with Rust and WebAssembly, enabling visitors to upload custom LED sketches via a local web server.
who should read it
Hardware hobbyists, embedded engineers, and generative art enthusiasts interested in physical computing builds.
discussion warm
consensus
Commenters enthusiastically praise the aesthetic and engineering of the project, while sharing practical tips for PCB manufacturing and hand-soldering SMT components.
pushback
A minor debate arose over the strict semantic definition of phyllotaxis and whether it accurately describes an electronic LED matrix.
author here, good digging! I added the MIT license.
Getting 5-fold symmetry to work was tricky, but the repo you found has the processing sketch where I figured it out. I basically took the point generation process I described and rotated it upon itself 5 times. I tested this with different radial symmetry numbers actually, and 5 also happened to look the best and also was convenient for manufacturing the PCBs.
Then I had AI add the ability to rotate a bounding rectangle for one 'quintant' around the shape, and found the division of cells which minimized the area, since PCB cost scales with …
The author provides direct insight into how they engineered 5-fold symmetry and minimized PCB area to reduce manufacturing costs.
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