Checking wiring connections for lights

Discussion in 'RGB Lights - Intelligent Pixels and 3-Channel RGB' started by BundyRoy, Apr 19, 2016.

  1. BundyRoy

    BundyRoy Senior Elf

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    I was putting some lights together tonight and when I was putting the heatshrink on I was think about ways of checking which pigtail pin was hooked up to +ve/-ve/data (ws2811 pixels) in the future as I wouldn't be able to see the soldered connections. So I thought I would check the wire resistance between pins at each end of the string to see what it told me. This is what I got.

    +ve in to +ve out - very little resistance (ie direct connection)
    +ve in to -ve out - higher resistance
    +ve in to data out - no connection

    -ve in to -ve out - low resistance
    -ve in to +ve out - higher resistance
    -ve in to data out - no connection

    data in to -ve out - higher resistance
    data in to +ve out - higher resistance
    data in to data out - no connection

    I've tested the lights and they work. I have not tested if a string connected downstream works yet as I haven't got another string with connectors on it yet.

    What this tells me is I can isolate the data pin from the +ve/-ve pins but I can't tell which one of the other two is +ve and -ve by using resistance measurements.

    If you forget the pin location is there a way of determining the +ve and -ve pigtail pins without cutting the heatshrink off and looking.

    I hope this makes sense and I hope the measurements I've taken are right. I've double checked but I could be going number blind.
     
  2. David_AVD

    David_AVD Good news, everyone!

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    It's not really possible to tell V+ from V- in a situation like that. Your best bet is to choose a pinout, document it and stick to it.
     
  3. OP
    OP
    BundyRoy

    BundyRoy Senior Elf

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    Thanks David. I figured that might be the case.
     
  4. OP
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    BundyRoy

    BundyRoy Senior Elf

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    Not that it really matters but I just noticed that there is a dodgy connection in the second last node of the string I was testing last night. Sometimes the last two pixels work sometimes they don't, depends on how you hold the wires. So the resistance measurements below may be influenced by that as well. I think it explains why I thought I was going crazy last night. I could of swore I measured the same two wires multiple times for different results. Looks like I probably did due to the faulty connection.
     
  5. scamper

    scamper Senior Elf

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    I agree, come up with a wiring standard for your lights.
    I chose what I thought to be logical, wired one up, took a photo and printed it out and then stuck it on my wall where I do all my wiring.
    After about the 100th time, you tend to start remembering :)
     
  6. OP
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    BundyRoy

    BundyRoy Senior Elf

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    Thanks Scamper/David. I do have a wiring pin out that I use and as you say it is easy to remember after a bit of repetition. My hassle is I have bought some second hand lights and the pin out is different to mine. Don't really want to change the lot but I can see having two systems will cause problems somewhere down the track. Was wondering if there was an easy way to check which pin was what.


    My other issue is some of the lights I bought are in plastic balls (opaque) so I can't actually see the pixel to determine which wire is which (all wires are black on string). Haven't had a hard look at the lights yet so am hoping the balls can be opened up without being destroyed.
     
  7. David_AVD

    David_AVD Good news, everyone!

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    Changing the other connector pinouts may be a pain, but hooking them up to the wrong system and blowing them is worse.
     
  8. OP
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    BundyRoy

    BundyRoy Senior Elf

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    Thanks David, you're confirming the thoughts I already had. Was just living in denial for as long as I could. The good news is it's a while to go before Christmas so there is time.
     
  9. the grinch

    the grinch I guess I could use a little social interaction

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    Not sure if I can help here or make sense but yes I try to keep it simple and yes absolutely do all work the same and do not cover up my work in a fashion that cant see what ive done heatshrink each wire individual then clear shrink on top so can see whats been done if needed .for dumb rgb pigtail connection
    Red to red some tails have brown wich to me is red
    Blue to blue
    Green to green
    Then black or white to black or white silly but is positive connection but works for me
    Must always check the rgb order as is different for different brands of lighting and batches .have found even as light or strip clearly marked + r g b wrong dont trust test first .
    Smart pixels
    Red to red or brown. positive power +
    Black or white to black or white . For negative power -
    Blue to blue
    Green to green
    Depending on types of pixels 3 or 4 wires
    Clock and data wires found mixed up frequently also worth checking
    I try to keep things as simple as possible and also if please no! But if trouble easier to fault find
    Goodluck hope can help
     

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