Why don't my null pixels light up?

Discussion in 'Lights - Store Bought and Home Made' started by Greg.Ca, May 9, 2015.

  1. Greg.Ca

    Greg.Ca Apprentice Elf

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    A few weeks ago I noticed that Ray was selling 'null pixels' for a dollar which included a input and output connector. These were 12V WS2811's. I had asked him to make me 100 of 5 Volt WS2811's which he did. My specifications were that each 'pixel' had a short input & output cable (3 core male-input and female-output 15mm cable). He did make these correctly and the actual pixel are all encapsulated with some plastic that does not allow me to actually see the pixel or the wiring. I do expect these to emit 'some' light when energized in my strings. These have normal quick disconnect connectors that quickly allow me to easily and quickly add them before any pixel string.

    Before I actually use any pixel strings or strips, I always test them with my home made 'pixel tester'. When given 5 volts and data, my pixel strings and/or strips always light up with some sort of a moving test pattern when connected to my pixel tester. Having lots of 5V pixels, this pixel tester is a blessing. It always works and lets me instantly know that my strips or strings are correctly working before I ever hook them up to any pixel controller. It's just a great tool.

    When I added this 'null pixel' either before or after any strings or strips of 2811's, it doesn't light up. It should be NO different that any other WS2811. Correct??

    It seems to pass data through it correctly, but why isn't it lighting up when hooked up to my pixel tester? Shouldn't this be a normal 2811 pixel? Am I missing something? --Greg--
     
  2. algerdes

    algerdes Al Gerdes

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    I'm not an expert, but I'll take a stab at it...

    A "null pixel" (NP) is used to regenerate the signal on the line. If it was built as I believe it was built, there isn't anything on it to light up. It would be the processing chip (WS2811?) without the LED (50/50?).
    When I put a NP inline, it is usually a burned out LED attached to a chip. The chip still functions.
    I know of others who cover the LED (tape, shrink tube, etc.) so that it does not shine.
    Sounds to me like you are ahead of the game here without the LED.
    If you can get a shot of the device and put it up here, we can tell you for sure.
     
  3. lizardking

    lizardking IT IS STILL ALL BENS FAULT

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    hey Greg a null pixel is not meant to light up what controller are you using as you need to set the null pixel in your set up as a null pixel if the null pixel lit up it would be counted in your pixel count need to
    1.check your settings for your controller
    2 does your other pixels in the string light up
    3. if your other pixels light up all should be good unless the last pixel in your string doesnt light up then the null pixel need needs to be calibrated
    hope this helps
     
  4. OP
    OP
    Greg.Ca

    Greg.Ca Apprentice Elf

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    Adam,

    I have 5 different controllers from J1Sys and now I have 3 Pixlite 16's from Advantek lighting. But as I said in my post, I'm NOT using a controller at all. I'm using a simple $20.00 pixel tester. See pic below. It has a built in pixel test feature that spits out data to test pixel strings and you see moving test patterns on the strings that are being tested.

    Everybody should have one of these in their toolbox. No computer is needed you just have to give it a 5V supply and it starts sending out data to pixel strings. Really cool. This pixel tester doesn't have a 'settings' page as do my actual controllers. I have hooked up to 240 5V 2811's in a row and it tests all of them perfectly.

    I'm just wondering why the first (null) pixel doesn't light up. I believe Algerdes may be correct. Because of the plastic encapsulation, I'm unable to see inside the plastic and there may be only the 2811 chip WITHOUT the LED. His answer makes perfect sense. Attached is also a link to what ray is making, the only difference is that my pixels are 5V instead of 12 V and my connectors ate 15 mm instead of 13.5 mm otherwise they look the same. --Greg--

    http://www.aliexpress.com/store/product/DC12V-WS2811-null-pixels-to-regenerate-the-data-signal-with-13-5mm-3-core-black-waterproof/701799_32279633328.html
     

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  5. dale82

    dale82 Senior Elf

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    a null Pixel is used to pass the DATA on down the line, After a certain distance the data tends to "fade out" (as I put it) and needs a null to re-generate the signal so that it can keep passing the data on. If you don't have a null pixel in place and your controllers are a fair distance away from your Props, you will get mixed colours and flashing etc. (Well that's what happened to me)
     

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