ws28xx-7-segment

[Work in progress!]

Large format time code display from WS2812 LED tape

(Slow Animated Gif - Click to View)

Using WS28xx/APA102/UCSx903/TLC59711compatible LED tape, it's possible to build a large format Seven-Segment display of variable size from 3D printed housing components. This clock will display the time code from the selected source.

There are many, many examples of these builds on Thingiverse, YouTube, etc.  This described build is based on the 3D printed frames from https://www.ivanmiranda.com/diy-big-digital-clock, but is adaptable to other arrangements.  Note: if building your own, there are some differences between Ivan Miranda's wiring and type of led tape used from this described build.

Individual digits are wired as follows:

   OrangePi Zero ---->  Hh Mm Ss Ff : : :

 
Digits 7 & 8 being the frame number, 1 & 2 being the hours. 
The colons are connected after the last digit,  for hours[]:minutes[:]seconds[:]frames.

(View from the back when flipped vertically - click to enlarge)


(Back view of one digit)

 LED Data Input --> A->B->C->E->D->F->G --> LED Data Output)

Note: We follow the standard wiring/manufacture of a Seven-Segment display (but we do not include DP).  This is different to the wiring described Ivan's video.

(Front View of Digit, Ignore DP. Source Wikipedia)


Instead of the Decimal Point (DP), we use a Colon, though the colons are the last things to be connected, making them optional.

(Colon Wiring)


Note: I used 12V  3 x LED per WS2812 Chip type tape (LEDS_PER_SEGMENT = 1), as shown below cut at blue mark, but you can quite easily modify the source code to use 1 LED per WS2812 Chip (LEDS_PER_SEGMENT = 3).   It is probably easier to use 5V LED strip directly, as 12V strip requires a level shifter to translate 3.3V oPi signal to 12V.


Totally Optional....

I built the controller into a small pelican case.   I used 12V LED tape, which required a level shifter, and  RS485 modules to extend the cable length between the OrangePi and the WS2812 display, by sending the LED Data OUT signal from the oPI to an RS485 module as shown below.   This is totally optional,  if you build the oPI into the first digit connect LED Data out straight to your first LED and not the RS485 module.



I chose to add a RS485 interface to my display, allowing the display to be further away from the the OrangePi.   You don't need to do this, you can go straight from the OrangePi to the 1st Digit, RS485 is entirely optional.







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