https://github.com/jagnat/fib_quintant_minimizer
It would be really neat if the author could put the relevant licensing stuff on there.
(but mainly, I want to hear about how they accomplished 5-fold symmetry!)
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 that.
Perhaps an example of convergent evolution? :)
With respect to the assembly: do yourself a massive favor and let the PCB fab also assemble the LEDs. With a simple bill of materials like this it will add very little cost, it saves you a _lot_ of time, and it might also reduce the chance of component damage from adding too much heat or from accidental ESD strikes. (I don’t know how much these Neopixels can handle, though.)
Of course, having a 5x PCB fab, but 4x+1 assembly would probably double the cost for a single turn of the device.
I would love to hear more about the process of making 5-fold symmetry work for board layout. That sounds maddening to get right.
I think your idea is pretty sound if you connect all but one of the boards in a ring and use a jumper for the control section.
I can only go so many days carefully monitoring diet and minimizing stimulant intake to minimize associated tremors. And I don't have rework microscope, so my eyes would definitely suffer.
Too bad. Software audio visualization's no longer common. But hey your hardware visualization's better than software! :D
This is by far one of the biggest areas where I could improve the design. I'm not happy with how fragile it is. The good thing about using just paper screwed from the top is it's thin enough to prevent light bleeding between cells.
https://music.apple.com/us/album/neon-pattern-drum/134973653...
Thank you for sharing the build process.
The trickiest part in these builds is usually balancing transient response with temporal smoothing so the LEDs don't devolve into jittery noise during busy frequency passages. Curious if you're doing per-bin decay filters on the FFT or handling dynamic gain normalization upstream?
I experimented with both approaches, and landed on mixing the band energy normalized by global energy vs. per-bin max energy, with a very arbitrary coefficient that seems to work. I also keep a few copies of the levels per band with different rates of decay, so I can add features in the sketches which should be sensitive to transients, vs. features which can rely on slower rates of change.
Not at all an expert in any of this and it was a lot of trial and error, still lots of room for improvement.
I understand it was inspired by https://en.wikipedia.org/wiki/Phyllotaxis, but arrangement on leaves serves the purpose of growth in a specific niche. The pattern arises because naturally leaves serve to capture light - see the images on wikipedia there. Phyllo means green. The LEDs used here do not really tap into any of that, and the name is also a misnomer. That's not good.
A trick that poor hobbyists learn early on is to make pads a little larger than necessary for SMT parts so you've got somewhere to wick solder onto. Neopixels (5050 LEDs) are reasonable to hand-solder since the pads extend up the sides of the package, but you can also do QFNs with a bit of practice by placing a big via to get to the central pad from underneath.