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RPi + OpenELEC WS2812B White Balance Calibration Problem

Discussion in 'Hardware Support' started by xriddle, 12 June 2017.

  1. xriddle

    xriddle New Member

    Messages:
    2
    Hardware:
    RPi2, +Arduino
    Hi All ,

    I'm new to the forum looking for some assistance if possible. What would cause my WS2812B strip to behave like this (see image) when displaying the White Balance PNG. As my strip progresses the LEDs become redder and redder. I've tried both through the internal grabber and the V42L grabber with similar results.

    Thanks
    x
     

    Attached Files:

  2. Akriss

    Akriss Active Member

    Messages:
    496
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    That's what I call an “Orange out”. It comes from voltage drops along the led strip. I had the exact same thing happen on my first attempt.

    The remedy was to feed each continuous strip of led with its own wire from the power supply. Keep in mind that each led consumes around 60 milliamps for each led, So if your led on the tv total say 250. Your power supply should be at a minimum 15 amps. 20 amps would be a better choice for wiggle room.

    Hope its of help.
     
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  3. xriddle

    xriddle New Member

    Messages:
    2
    Hardware:
    RPi2, +Arduino
    thanks for the reply. I'll give it a try and report back.
     
  4. IKnowCodeSoup

    IKnowCodeSoup New Member

    Messages:
    12
    Hardware:
    RPi1/Zero, RPi2, RPi3, +Arduino, +PhilipsHue, +nodeMCU/ESP8266
    Running wires works well but it's a fair bit messy. Not something you want to get snagged on something and start a fire by grounding out.

    My go-to solution these days is to cut the 5v line of the whole strip somewhere in the middle (don't solder a corner if running a full set, or cut the very middle of the top strip when running power from the gap at the bottom if you have one).

    Then, no wires to run. Just put a capacitor on each half. You can run rather small ones, but I enjoy overkill so I put a 1000uF on each.
     
    • Like Like x 1
  5. Akriss

    Akriss Active Member

    Messages:
    496
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    Hmmm, I think I'll rework my mess.
    [​IMG]


    Thanks for the tip.:thumbsup:
     
  6. Braulio

    Braulio Member

    Messages:
    31
    Hardware:
    RPi3
    Hey @Akriss, did you add the capacitor?
    I need to do in on my too.

    Not sure what @IKnowCodeSoup said, we have to place a capacitor in the middle of the LED strip?
     
  7. Akriss

    Akriss Active Member

    Messages:
    496
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    I added one (1) capacitor to one strip of 165 leds on a setup I did. It works fine.

    However I have another setup without a capacitor,it has run fine for 18+ months.

    I tend to forget about the cap.
     
  8. Braulio

    Braulio Member

    Messages:
    31
    Hardware:
    RPi3
    Nice to know!
    Did you add at the begining of the LED strip?
     
  9. Akriss

    Akriss Active Member

    Messages:
    496
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    I made a power distribution block (from a breadboard) that splits the power to each strip/side. The capacitor is fixed to the distribution block. The distribution block is centered on the back of the TV. One input and four outputs.
     
  10. Braulio

    Braulio Member

    Messages:
    31
    Hardware:
    RPi3
    Interesting!
    Thanks for sharing!
    Is the capacitor 1000uF and 5v?
     
  11. Akriss

    Akriss Active Member

    Messages:
    496
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    If I remember correctly it was a electrolytic capacitors - 1000uF/25V.
     
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