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Phyllotaxis: An audio-reactive LED displayjagi.studio

One of nature's beautiful patterns captured in dancing lights

331 points•evakhoury•2 days ago•48 comments•
#reactive#audio#led#display#phyllotaxis#audio reactive#reactive led#led display

48 comments

throwaway2194502 days ago
Very cool. 5-fold symmetry on the PCB to use up the board allowance is particularly neat.

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.

XRG2 days ago
Love how the 5 PCBs slot into each other to form the final shape.

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.)

petsfed1 day ago
I'll bet there's some creative board layout so that the relevant controller IC and supporting passives can be soldered onto the back of one of the 5, then have solder jumpers or some such to actually connect it into the circuit. That way, you're not adding miles of unused trace to an active bus.

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.

throwaway2194501 day ago
As long as you can design the outline as a vector file somewhere else, it's easy enough to import as a board outline and then lay out on top of it. I also get the lure of assembly these days, but I would hand-solder a board like this for a one-off art project. Call me old fashioned, but I'm confident enough with soldering that I'd estimate a couple of hours to assemble and I like buying domestic which is less economical than the JLPCB special. If people started to ask for kits though...

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.

scoot1 day ago
> do yourself a massive favor and let the PCB fab also assemble the LEDs

From the article:

What's next? ...using PCB assembly...

asdfasdfe1 day ago
I don't agree with this. The board and components are trivial to hand solder.
lukeify2 days ago
Cool! Remarkably similar to Voria Labs who produce a product called Lumanoi https://voria.com/

Perhaps an example of convergent evolution? :)

pbronez1 day ago
The common element appears to be the use of a Voronoi tessellation to map a field of scattered points (LED locations) to cells.

https://en.wikipedia.org/wiki/Voronoi_diagram

asdfasdfe1 day ago
I see only a very slight superficial resemblence and non of the inner works are related at all.

Where do you see similarities?

busssard1 day ago
its an organic looking cellular light sculpture for walls
realo1 day ago
Well...

I bought one of those some time ago.

Might interest the HN crowd...

https://www.evilgeniuslabs.org/one-inch-fibonacci128

petsfed1 day ago
Because I desperately want to make my own (and maybe modify it a bit to fit my own hardware biases), I found the repo for the hardware:

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!)

jagiii1 day ago
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 that.

h-c-c1 day ago
Friend, if you can find one, get yourself a Fadecandy board. Maybe not that easy since it's technically discontinued. The dithering gives the smoothest / sexiest fading possible.
Already__Takenabout 22 hours ago
if you can manufacture the board on both sides you can probably alternate top/bottom and panel rows with no waste in a straight line.

Read the full thread on Hacker News →

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