Pixelblaze Volumetric Cube

Pixelblaze Volumetric Cube

Firework nova (now on the pattern site!)

Thread on the build

To music:

This is a volumetric LED cube made up of 64 x 8 pixel strings, run from a Pixelblaze V3 with 8 x 8 channel output expanders (for 64 outputs total), 512 LEDs in all, measuring about 2ft per side.

3D printed clips hold the LEDs in position with the wire, and provide some diffusion. The LED strings hang from a panel which also houses the electronics.

A Sensor Expansion board provides the sound and music reactivity with 32 band spectrum analysis. The pattern shown is spectromatrix playing with Sacramental by Joseph Hencke.
http://josephhencke.com/

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Such amazing visual impact!

Was the most laborious part the printing, crimping 64 servo-connectors, something else?

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@jeff,
Thanks!

Yep, cutting the strings of 50 LEDs into 8 pixel segments, soldering to the servo type wire leads (sometimes with extensions) all with heat shrink.

The other part was 3D printing and installing 512 clips/diffusers, but it looked pretty good, if a bit chaotic, without them and was good inspiration :slight_smile:

The rest was a snap for a build that would otherwise be this complex. The output expanders each got their own power, with one shared data line down the middle, and distribute power via the leads which at that point just plug in. So power and data routing was really painless.

Another advantage of this build is that its way less fragile than other volumetric cube builds I’ve seen, and more portable for its size since the strings aren’t rigid and can collapse.

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This just looks really, really fun. Makes me want to go build something large too!

Nice project. I am having problems with the pattern trying to download to the pixelblaze. The pb kind crash and wont show the pattern.

That’s a nifty clip. Tiny but effective. I like the way the wire clips in.

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What kind of connectors are those blue ones for the 3 pins?

@LostPanduh,
Are you asking about the top side of the wood panel, where the wiring is shown?

That blue is the glow of the LED coming back up through the transparent LED module housing (the “bullet”) and glowing through the hot glue that’s holding them in place where holes were drilled in the wood. The holes had to be big enough for the bullet + wire, and were snug enough to kind of hold them in place temporarily, but they would wiggle and fall out without the glue. Using hot glue meant I could replace them if necessary.

For connectors, I used servo style wire leads (similar to the “dupont” wires) and soldered them to the wires of the LED modules. That can then easily plug in to the Output Expanders.

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Yes that’s what im talking about. Amazing! this project can work with v2 too? is possible to make it simple with pcb rows i plan to order from a pcb company ? they can make any pcb you like etc. if its possible then i need the scheme for the bottom pcb all rows will connected on to send to them for print the pcb for me. Also 8 channels expander ? More patterns for cube in future?

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Yes, V2 does all the same stuff, though V3 is 2.6X more FPS on average which helps with this many LEDs and 3D patterns.

It is possible to make rigid LED strips or grids and assemble them into a cube, the main issue is that those LEDs tend to have a narrow viewing angle and the PCB blocks 180 degrees.

The 8 channel expanders come in handy when you don’t have a return data path!

Transparent aluminum… Ok ok, it’s just a transparent PCB and it’s plastic.

But you could order a complete PCB, LEDs and all, and bingo insta-cube.

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If someone does design a clear planar PCB with LEDs in a matrix, and gets pricing, let us know.

If you wanted a cube, you’d need to have X PCBs where X is whatever size of matrix you built, so 8x8 LEDs (64 ws2812s) would need 8 clear PCBs as well. But then ideally you’ll just solder data in, data out, daisy chained, starting at your Pixelblaze, and connect power to each PCB. (Ideally, no soldering at all, if the PCB has good connector for all of that)

So a clear cube of 8x8x8 (512 pixels) could be an order of 8 boards away. But what would the cost be? And the size? Big enough to make all pixels visible?

I just stumbled across this WS2816 LED curtain on Alibaba:

The sheets aren’t large enough for an architectural application like Wizard’s cube, but it could be a cheap-ish (about $0.07 per LED) way to do a larger rectangular matrix (I counted 64 across one row, and I think you can get as many rows as you’d like).

You might even be able to separate the strands if the transparency is what you’re after; the edge connectors at one end and the loopback at the other make me think that each pair of columns is an independent strand.

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Thanks for posting this, and your info via email. I’m going to try replicating myself. (Hope that’s ok)

I’ve ordered 550 of the bullet style LEDs, just grabbed some wood from home depot today, got the PB + expander mounted on some breadboard…. Now the waiting game from AliExpress on the LEDs…

In the meantime I guess I can get the pixel map, expander settings and pattern dialed for my intended wiring? Thinking I’ll run a return data line up each string to allow wiring each 8x8 plane to a channel (so just one expander board instead of 8 to run the cube).

Couple follow up questions on your build details… hope you don’t mind.

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  1. The video showing the pixel map and pattern code on the Twitter thread is a bit blurry so can’t read it. any chance you can post here as a starting point?

  2. Also for the patterns, is there a good way to search for it? On the electromage site it seemed only possible to look at “recent uploads” or “popular”, but I’m likely missing something obvious.

Thinking I’ll try this cube out to cut my teeth on PB, then move on to writing a driver for those pesky dmx412 LEDs on the other project I have going….

It was more or less the built in example volumetric cube with a few coordinates swapped around so z went down.

For patterns, the site could use improvement, especially with how active the community has been contributing to the list!

For now it’s just paging, firework nova is the one featured in the video mostly. Many of the others are preinstalled. Fast pulse, cube fire, spextromatrix, are some others.

The coordinate transformation api was added after that post, and would improve many of the patterns!