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Controlling multiple WS2812B via UNO

bassslapme

So I have been asked to install a bunch of LED's into a friends fight stick as he knows nothing about them whilst I have a little experience with them. I have used WS2812B's as a backlight for my TV and used a HM-10 for it so i could make an app for it.

I wanted to reuse the app I made as it would mean cutting down the coding process, but I can't get my head around how I would control multiple sets of the strips. I would daisy chain each strip together via the DIN and DO, but when I put this in practice it just lights up the whole strip with whatever I set the first strip to. I believe maybe defining the individual strips would work ( # define LED_STRIP_A)

and then defining how many led are in that strips and applying the code for the different effects or just the RBG value for each pixel would work but I would like some pre-mental breakdown advice before I plunge into this and fail.

  • I believe maybe defining the individual strips would work ( # define LED_STRIP_A)

    and then defining how many led are in that strips and applying the code for the different effects or just the RBG value for each pixel would work but I would like some pre-mental breakdown advice before I plunge into this and fail.

    You have already answered... using different LED strip with different instantiation of class (means objects) on different pins of arduino will surely work as expected...

     

    , but I can't get my head around how I would control multiple sets of the strips. I would daisy chain each strip together via the DIN and DO, but when I put this in practice it just lights up the whole strip with whatever I set the first strip to.

    but If you connect similer type of neopixel strip with DIN-DOUT than you will get mentioned problem due to LEDs with same address on every strip..

  • I've not yet used WS2812 on the Arduino but have built quite a few circuits using the Microchip PIC range. So, although I'm not familiar with any of the WS2812 Arduino libraries this is wha I'd have done in the PIC C code.....

     

    When you daisychain the strips together, is your code not pushing out just enough data to light the first strip ? Perhaps then, when it wants to refresh that strip it pushes that data further on out through Dout and into Din - and so illuminates the second strip (as you are seeing) ?

     

    You could: Set up an array to hold the RGB data and ensure it is long enough to hold data for all the elements you require daisychained. To do something specific to the nth strip you would manipulate the array contents directly. Then at regular intervals (say 50ms)  - push the whole array out on a single Arduino pin to the daisychained WS2812.

  • Each LED in the strip is addressable.

    My understanding is that each WS2812 takes the data in, and subtracts one from the address and passes it out the Dout.

     

    For this example lets assume you have 4 lots of 10 LED's. You can address all 40 and use a loop to assign the RGB setting to 0-39

    OR you could have 4 seperate loops of 0-9, 10-19, 20-29, 30-39 and set the colour for each of the LED's and step through the 10 times to give the effect.

     

    You can send all the settings and then execute the strip.show which makes them display the revised setting.

    So in essence the LED's are doing the data array for you.

     

    If you are worried about persistance of vision, then the DotStar use a data and clock and can run much higher data rates.

    https://www.adafruit.com/product/2343

    https://www.adafruit.com/product/2237

     

    Hope this helps.

    Mark