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Thread: Decorative LED cube - GIF

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    16x16x16 LED cube? So 4096 lit elements, which are RGB, so 16384 LEDs. I'm not seeing a lot of wires. Are these digitally addressable in some way, or maybe some really complex charlieplexing going on? I'm sure it's digital because that would be easy, but really I hope it's charlieplexing.

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    Quote Originally Posted by nova_robotics View Post
    16x16x16 LED cube? So 4096 lit elements, which are RGB, so 16384 LEDs. I'm not seeing a lot of wires. Are these digitally addressable in some way, or maybe some really complex charlieplexing going on? I'm sure it's digital because that would be easy, but really I hope it's charlieplexing.
    They are regular RGB LEDs that are wired together into a matrix via their leads. If you look closely, there are 16 panels of LEDs that we see end on for much of the video. To address an individual LED they use the panel, row, and column numbers. I have wanted to build one of these for years, but it's terribly fussy building all the panels. Most folks use various forms and templates to get the LED leads bent just right and the LEDs all evenly spaced. Oh, and the silvery LED leads and solder help disguise all the connections that are there.

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    Quote Originally Posted by schuylergrace View Post
    They are regular RGB LEDs that are wired together into a matrix via their leads. If you look closely, there are 16 panels of LEDs that we see end on for much of the video. To address an individual LED they use the panel, row, and column numbers. I have wanted to build one of these for years, but it's terribly fussy building all the panels. Most folks use various forms and templates to get the LED leads bent just right and the LEDs all evenly spaced. Oh, and the silvery LED leads and solder help disguise all the connections that are there.
    I'm not sure about that. Pause the video between the 0 and 3 second mark. I don't see any horizontal wires at all. If you look close there are only vertical wires on the clear plastic. Also if you were scanning that many RGB LEDs it would be extremely difficult to PWM all the lights correctly to get different colors.

    I think it's something like a bunch of WS2812B or SK9822 strips adhered to acrylic or polycarbonate sheets. If I were building it that's what I'd do. You can just peel the adhesive backer off the LED strips and stick them to the plastic. Everything's done for you and you don't have to run wires. Then you only need common power and two data wires off the bottom of each strip (in the base). It's still a bunch of wiring, but it's not 4096 wires in a full blown matrix.

    Edit: For a matrix you'd need 12288 wires, not 4096. Whoopsie. For addressable strips you'd need 512 wires and each strip would be connected to a common power and ground.
    Last edited by nova_robotics; May 19, 2022 at 12:36 AM.

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    Quote Originally Posted by nova_robotics View Post
    I'm not sure about that. Pause the video between the 0 and 3 second mark. I don't see any horizontal wires at all. If you look close there are only vertical wires on the clear plastic. Also if you were scanning that many RGB LEDs it would be extremely difficult to PWM all the lights correctly to get different colors.

    I think it's something like a bunch of WS2812B or SK9822 strips adhered to acrylic or polycarbonate sheets. If I were building it that's what I'd do. You can just peel the adhesive backer off the LED strips and stick them to the plastic. Everything's done for you and you don't have to run wires. Then you only need common power and two data wires off the bottom of each strip (in the base). It's still a bunch of wiring, but it's not 4096 wires in a full blown matrix.

    Edit: For a matrix you'd need 12288 wires, not 4096. Whoopsie. For addressable strips you'd need 512 wires and each strip would be connected to a common power and ground.
    There aren't any horizontal wires from that angle. The panels are each standalone, so each panel is a flat matrix of LEDs with interconnections between the panels hidden in the base. Here's a video showing how that one was made. It may not be the simplest way, but it worked. And I've been thinking about using very small form factor addressable LEDs to make one of these with thin wires making the interconnects, instead of tape. It would still be a nightmare to build, but less work than what he went through.


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    Quote Originally Posted by schuylergrace View Post
    There aren't any horizontal wires from that angle. The panels are each standalone, so each panel is a flat matrix of LEDs with interconnections between the panels hidden in the base. Here's a video showing how that one was made. It may not be the simplest way, but it worked. And I've been thinking about using very small form factor addressable LEDs to make one of these with thin wires making the interconnects, instead of tape. It would still be a nightmare to build, but less work than what he went through.
    Quite the build. Very impressive. I thought it was adhered to plastic sheets but nope, the wires and LEDs are free standing. Amazing. The LEDs are addressable though. Check out 4:33 in the video. Did you catch a part number for the LEDs in that video? I didn't see anything. Each one gets power, ground, data in and data out. He's using a Teensy 4.0 and 3 data pins are used to drive 128 LEDs.

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    It has been a while since I last watched this video, so I forgot he was using addressable LEDs (WS2812s). There was another video like this one, where they guy was using common cathode (or anode--I forget which) RGB LEDs to do the same thing, but he had to address them by their matrix location, not their order in the chain. I hope he found a good source for bulk LEDs, though, because by my calculations, he has around $3,000 in LEDs, alone, in this project! Here's a link to LEDs like the ones he used:

    https://www.sparkfun.com/products/12986



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