Truncated Icosahedron (soccer ball)

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Made a truncated icosahedron (soccer ball) out of 32 PCBs (12 pentagons, 20 hexagons) joined by 3D printed corner connectors and covered with 3D printed diffusers. Each PCB contains 32 side-emitting LEDs per edge. My goal was to create a hollow shape that would let you see the patterns covering the whole structure. As a bonus, the near-spherical shape makes the assembly pretty sturdy.

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This looks super cool !

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The patterns work great on it too! Did you spend a long time writing and tuning them?

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Wow, you always amaze. Great job.

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Almost none at all. Most of the playlist is 3D patterns which look great unaltered. I’ve also had success mapping 2D patterns to work on the surface of a sphere by calculating the normalized azimuth and polar angle for each point and mapping those to the values of X and Y for some 2D patterns.

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Do you have a guide/write up on how you did the polar to Cartesian mapping you’ve described? Sounds very useful

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This looks amazing, I can imagine several of these as chandeliers for a stage.

Did you 3d print the PCBs or did you source them from somewhere?

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Sure. For every pattern that has a render2D, but not a render3D, I add this render3D function:

// This function computes spherical values with each call
export function render3D(index, x, y, z) {
  x -= 0.5
  y -= 0.5
  z -= 0.5
  render2D(index, 0.5 + atan2(y,x)/PI2, acos(z/hypot3(x,y,z))/PI)
}

It maps with distortions, but generally looks pretty good when mapping 2D functions to the surface of a sphere. Not sure how good/bad it would look with other 3D distributions of pixels.

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I ordered the PCBs and had PCBA done by JLC. It’s not too costly as these things go, since each PCB contains only LEDs and capacitors. I also 3D printed corner connectors with heat set inserts that hold the PCBs together and diffusing covers that sit on the outside of each PCB to diffuse the light.

I will eventually get around to publishing the details of this project, though probably not for a few weeks yet. I think it’s reasonably buildable by most makers with good soldering and 3D printing skills.

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I look forward to your full write up!

I have the soldering skills but have yet to dive into the world of 3d printing. I am going to get a 3d printer pretty soon and will eventually start brushing up on Blender.

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