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RPi + OpenELEC WS2801 needs strong color adjustments

Discussion in 'Hardware Support' started by Blu3ye, 16 June 2016.

  1. Dirk

    Dirk Member

    Messages:
    54
    Hardware:
    RPi2, RPi3, +PhilipsHue
    If your TV has at least 8 Zoll distance to the Wall 36 is enough.
    Under 8 Zoll 60 looks better.
     
  2. Pieface

    Pieface New Member

    Messages:
    19
    Hardware:
    RPi3
    Does anyone have their TV mounted against a wall? If so - does it work okay?
     
  3. Dirk

    Dirk Member

    Messages:
    54
    Hardware:
    RPi2, RPi3, +PhilipsHue
    I have a swiveling tv wall mount and this works great.
     
    • Agree Agree x 1
  4. Blu3ye

    Blu3ye New Member

    Messages:
    10
    Hardware:
    RPi1/Zero
    What does that mean? Can I figure it out by myself?

    I´m wondering why there are so many tutorial with WS2801 if it is "known" there are more problems like this? Can´t imagine that Aki(?) from powerpi.de would choose this without thinking over it. He also uses WS2801 in his tutorials and has a good white default with just a little need of adjustment.

    These stripe I got from Hello Fish do look like good quality. No welding issues or similar. Also the feedbacks on Aliexpress look good and for what I have found with a quick research APA102 are not that much more expensive?!

    After calibrating I´m having an even more bad ambilight experience. It´s like normal colors are way to bright/less saturated and dark scenes are much too strong and often "dark red/orange" or "purple" when it should be nearly black! Not making fun right now... =(
    Spent much time with the calibration and with the calibration pictures everything looked great but with live program it´s not... any hints for me?

    Will take some pics when the sun goes down to show it - or should I make a new thread for this?
     
  5. Dirk

    Dirk Member

    Messages:
    54
    Hardware:
    RPi2, RPi3, +PhilipsHue
    • Like Like x 1
  6. TPmodding

    TPmodding Administrator Staff Member Administrator

    Messages:
    1,840
    Hardware:
    RPi1/Zero, RPi2, RPi3, +Arduino, +nodeMCU/ESP8266
    • Like Like x 1
  7. penfold42

    penfold42 Active Member

    Messages:
    746
    Hardware:
    RPi1/Zero, RPi2, RPi3, 32/64bit, +Arduino, +nodeMCU/ESP8266
    The ws2801 is just a chip - it's up to the strip manufacturer how they implement it and their level of quality.

    The datasheet has some worked examples on what the resistor values should be.

    Green and blue LEDs have a similar forward voltage drop so their resistors are often the same value - typicaly 100 ohm
    Red LEDs have a lower voltage drop so need a higher resistor - 130 or 150 ohm

    Those resistor values are just from randomly looking at photos on eBay and j can already see some variation before we look at manufacturing errors.

    You'll need a multimeter to truly test how it's wired and the resistor values
     
    Last edited: 18 June 2016
    • Like Like x 1
  8. Blu3ye

    Blu3ye New Member

    Messages:
    10
    Hardware:
    RPi1/Zero
    Finally... finding some time again to carry on this problem.
    I tried to take pictures that show how the LEDs look like before and after adjusting the settings. Yes, it does look a little stronger in darkness with a camera than it is, but thats far from what should be I guess.
     

    Attached Files:

    • Like Like x 1
  9. Dirk

    Dirk Member

    Messages:
    54
    Hardware:
    RPi2, RPi3, +PhilipsHue
    With my ws2801 i had almost the same Values to get a good White. After i changed to the Apa102 my Values are 255 255 255.
     
  10. LooseChange

    LooseChange New Member

    Messages:
    24
    Hardware:
    RPi2
    I have the same issue with ws2801 but I hot glued them to the tv. Yellow never looks right does it? The Apa102 are pretty expensive right now, I am going to stick with the ws2801 for a while.
     
  11. mikeB2210

    mikeB2210 New Member

    Messages:
    22
    Hardware:
    RPi3
    I have a question about the powersupply: I'm using a 5V/20A supply.
    Is it possible to use this with the APA102/60. The length is 4,50 meters
     
  12. cocrea

    cocrea New Member

    Messages:
    7
    Hardware:
    RPi2
    yes they do need strong color adjustments, i get really good results with :
    white at R:255 G:74 B:46
    gamma: R:3,04 G:2,5 B: 2,5

    I am having problems with overall brightness though since updating to new version of hyperion... I dont think its a chip problem though


    -> if somebody has left some apa102 over and wants to sell them please contact me via PN. if i can get enough leds for my 49" TV i would like to give these leds a try.
     
    Last edited: 18 August 2016
  13. cocrea

    cocrea New Member

    Messages:
    7
    Hardware:
    RPi2

    APA102/60 uses max 18W/m
    18W/m x 4,5m = 81W

    Your supply offers 5V x 20A = 100W

    So yes, this should work you even have some reserve.
     
  14. Blu3ye

    Blu3ye New Member

    Messages:
    10
    Hardware:
    RPi1/Zero
    Hi guys!
    It´s been a loooong time now... but really I didn´t manage it to carry on this problem until now.
    I´ve switched to a RasPi 3 with OSMC in the meanwhile, but still with this issue.

    BUT after playing a few minutes again with the testpics and color calibration values I noticed something:

    I am getting wrong colours when switching from black to e.g. f3f3f3 grey image (leds are low light red).
    But when switching from white image to f3f3f3 grey image led colour is good!

    So I guess that is the source of my problem why calibration with images is ok but when watching live media colours are often way to strong or wrong.

    Did ever someone notice that on his leds, too or has an idea from where this strange behaviour could come?

    I got an second led stripe from the manufacturer that time for free because of my issues but I don´t think that will solve it?!