RGB LED CUBE with teensy

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carp88

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Hello my name is andre and I'm from Germany. I want realize a 16 x 16 x16 (4096 leds) led cube with 8mm rgb leds which I want to drive by an ws2811 ic (No classic strip). At my investigation I find the article about the Octows2811 library on your site. On the basis of this article I want to controle all leds by four teensy 3.2. Every teensy should controle 1024 leds (8 stripes/ 8 pins a 128 leds). The big led array for this project should be generated by a central teensy 3.6 which transmit the array by spi to the four teensy 3.2. I want to have a central teensy for upload and want to generate 200 fps.

My questions:

1. It is possible to realize my project on this way ?
2. Can I use the video sync when the led array transmit by spi ?
3. Is there a cheaper way to realize it ?

Octows2811 site : https://www.pjrc.com/teensy/td_libs_OctoWS2811.html

Thank you in advance for your answer!
 
software side of this is not hugely complex, but involve some work taking the movietoserial code and converting it to SPI transfer which is after all still just a stream of bytes, probably using the existing sync pin and logic.

Where life gets complex is actually building the thing, and none of them are going to be cheap if you include your time. large RGB LEDs are available with the WS2811 driver built in, which may be a useful option. As might be classic flat modules as soldered to strips in possible hand crafted dead bug or tomb stone configurations.

What can be pretty certain is that you will need to build a lot of prototypes to explore options and actually see the light produced, and how the dark body area of various designs trade off. For that you need to think about:
How will power get around this
How long does it need to last
How will you get at the middle to service it
Will you need to ship it/otherwise subject it to loads
Will it be viewable from multiple directions
Will design make a feature of curling wires everywhere, or is the aim to be a true 'lights hover in the air' result that needs to hide everything
Does it need to reproduce photo's/flesh tones (consistent brightness/colour)

If the aim is a striking lighting effect that is viewable from multiple directions a 2D array of pixels topped by vertical light pipes in varying heights would be simple engineering if expensive and unable to place pixels in all potantial spaces
If aim is a true grid but signficant visual obstruction is OK hanging vertical strands of pixels will be relativly cheap and easy to work with

If I had the direction and an unlimited budget I'd personally go for vertical metal rods for power and ground and dead bug strip style pixels between them with a gem shaped diffusor on top, embracing the power supply as part of the design. Zig zag the signal wire up on the finest wire you can work with. Given how long it took to make a stack of six this way once, the sheer amount of very fiddly, high failure rate hand assembly soldering means I do not actually suggest you try it unless you can make a machine assembly system just for this task.
 
Thank you for your answer.

The building is prepared. RGB LEDs with integrated ws2811 driver looks not well in my opinion. The brightness and the tone of coulour looks not fine. Additianally they are not cheap. Flat modules have the disadvantage that they dont visibel from multiple directions and this is a deciding feature of a 3d Cube.

In my solution the 8mm leds, the drivers and the resistors ect will be placed on a special pcb (16 leds per pcb) . Total i will need 256 from this to place all 4096 leds. These pcbs should be paleced vertical on a base - pcb . The power and ground should be distributed by the base-pcb to the led pcbs. The teensys also will be placed on the base- pcb with traces to control the leds.

Like this:
https://www.youtube.com/watch?v=XESEVlQbWkE

To your questions:
Power distribution by the base-pcb wich is support by some power adaptors
I want to genrate 200 fps! If i use the Octows2811 Library and spi I should generate one frame in 0,005 s (theoretically)
Photos or videos are not the target but a nice additional feature .

The rest should be clear after the video ;).
 
One Teensy 3.6 with 1 Octo board is probably easiest. It can handle 4096 LEDs.

Consider most WS2812 chips use 420 Hz PWM internally. 200 fps is only 2 or 3 of the internal PWM cycles, so you will have much less color accuracy depending on the alignment of your update rate and the internal PWM of the LEDs. I recommend running no faster than 60 fps.
 
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