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8x8LED modular and grid-ready!

Yet another WS2812B 8x8 RGB array, but modular and designed to match the pitch of typical "troffer grids".

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There are MANY WS2812B (and related) matrix layouts out there, and of course LED-strips.
However, I've never found any LED arrays (yet) that are the right pitch - to match the typical chromed-plastic "troffer grid" you find at popular DIY-home stores. In the USA, typically that means Lowe's or Home Depot.

With a unique modular approach, not only does this PCB fit the grid openings perfectly, but you can also more easily couple the +24VDC/GND rails in a planar fashion. Not only providing an electrical connection, but a structural one as well.

REDESIGNED! The original 8x8 display board only hosted the WS2812B LEDs, now it's got a whole system on each board, which can easily run standalone or in large arrays.

I started this whole system design over a year ago, and recently had a epiphany which led to a complete redesign.

This is just the first of several boards of my "system", which will consist of:

* 8x8 LED matrix module, consisting of a simple 8x8 array of WS2812B (or SK6812-RGB or even -RGBW!).

* WiFi interface/control module. Probably ESP8266 based.

* Backup-battery subsystem (2x 12V SLA's = ~24VDC).

The new 8x8 display board now integrated its own PIC micro, plus serial-flash for the playback frame-buffer.

Each of these display modules can be easily daisy-chained using CATx (UTP) cable fitted with standard RJ45 connectors.

Almost no power wiring! The display boards are generally laid out next to each other, touching. Linking the +24V and GND rails is really easy - just use standard "barrier terminal block" jumper straps. They are readily available standard bits (Cinch P/N 141J-1).

Distributed +5V: Rather than one giant (+5V @ 100amps?), each display module has its own 5V SMPS block, capable of accepting the 24VDC external power rail.

The SMPS block is designed to work with 9-24VDC, but to minimize losses in the wiring, it's best to stick with 24VDC.

TopAssy_LED-Troffer_2x4_view3.PDF

Typical 2ftX4ft "troffer" application, front side view (plastic diffuser lens in place too).

Adobe Portable Document Format - 980.84 kB - 04/13/2017 at 03:22

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TopAssy_LED-Troffer_2x4_view2.PDF

Typical 2ftX4ft "troffer" application, close-up view.

Adobe Portable Document Format - 674.13 kB - 04/13/2017 at 03:22

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TopAssy_LED-Troffer_2x4_view1.PDF

Typical 2ftX4ft "troffer" application.

Adobe Portable Document Format - 657.58 kB - 04/13/2017 at 03:21

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LED-sign_16x16_rear_closeup.PDF

Close-up view of the typical stackup... 8x8 LED matrix board (up to 144 per system), then a power-supply module (N per system), and finally the matrix-controller board (1 per system).

Adobe Portable Document Format - 554.57 kB - 04/13/2017 at 03:07

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LED-sign_72x32_rear.PDF

Rear view of "troffer-grid" sized array. Also shows the +5/GND interconnect scheme, 5 power supply modules, and one matrix control board (mounted on top of rightmost power module)

Adobe Portable Document Format - 370.27 kB - 04/13/2017 at 03:05

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  • 64 × RGB pixel, WS2812B
  • 1 × PIC16F1789 Microprocessors, Microcontrollers, DSPs / ARM, RISC-Based Microcontrollers

  • Progress...

    kbdhog04/13/2017 at 03:31 0 comments

    31-AUG-2017: Rev-B boards have arrived from easyeda.com They look very good. Now to put some parts down and start testing!

    19-Aug-2017: REDESIGNED!!!

    I redesigned this board almost from scratch. I still have a bunch of blank Rev-1 boards, and there's nothing wrong with them at all. Maybe I'll use them in some other application.

    The reasons for the redesign:

    To really build a system with these 8x8 panels (like a typical suspended-ceiling troffer, 36 modules), the main problem is with 5V power... You really need quite a beefy 24V->5V regulator to drive all of them. "Beefy" = can be difficult to design & perfect. Therefore, I elected to combine the simple 8x8-RGB matrix of WS2812B's, with CPU/flash circuitry from my other project "RGB pixel player", and an appropriate (smaller) 24V->5V regulator.

    So, Rev-B of this 8x8 module will have an on-board CPU & flash (frame-buffer), plus an appropriate voltage regulator. Once set to "play" mode, it runs standalone with no external supervision. The main power bus (mechanically coupling neighboring boards together) is now 24V (not 5V). Overall, a compromise, but more manageable (for me).

    Boards just went out to fab at easyeda.com (my first try with them). Hopefully they will be good quality with no issues. Stay tuned!

    Of course, once this board is working, I have a ESP8266 interface board to drive this whole mess coming out next...

    ********************************************
    Previous design (Rev-A) notes:

    12-Apr-2017: Just got around to moving forward on this project/system. It's been sitting around almost a year. I have blank PCBs and components for the 8x8 module, just need to throw some together and test it out! After that... finish my LED controller board, the WiFi board, and of course the modular power board.

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