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Thread: teensy octows8211 cat6 wiring how?

  1. #1
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    teensy octows8211 cat6 wiring how?

    Hey all - I've got most of the gear together for an 8 strip play with leds and the octo adapter, sweet!

    My first head scratcher question is ... each twisted pair is to be connected to an led strip (along with power of course) but ...

    if the strips are not close together, how to run the twisted pairs? Since cat6 is shielded, and I guess that's the point, if you just strip it back and run the pairs to where they go that would defeat most of the point.

    Does one pierce the jacket and pull a length of twisted pair back out of that hole then trim it back to appropriate length?

    Really only seems to be those two options, not overly confident it will be easy to pull a threaded pair out of the length of a 20 foot length of cat6?

    This is for a house christmas lights project (of course!) so, there will be opportunities to colocate strip ends near one another at say the corner of a window, but along the eaves, the data wires just have to run 16.5 feet *per* strip to get to the next strip.

    It has probably been asked in another thread "how long is too long" for the signal to stretch from the Octo to the strip, but I'll ask that again here too :-)

    Thanks!

  2. #2
    Senior Member crees's Avatar
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    What you have will get you started in playing with pixels and code. To make a Christmas light show will take some more engineering and parts. Distances will vary but I have gone up to 90ft inside testing but was unable to make it work outside due to the environment / noise. Pixels want a perfect signal and CAT5/6 does a really nice job. What you want to do is connect your pixel as close as possible to the octo board. As it sits, yes your setup will require you to strip back the cable pairs and connect them to your pixels with the power supply connections. (Octo Grounds with power supply ground & Pixel Ground, Positive power supply to positive pixel power and Octo Data to pixel data). Note power needs to be close to the first pixel with correct gauge and preferably fused. Also your setup is strictly for 5v pixels. Be careful if using 12v and that it is not powering the teensy without a proper regulator circuit etc. Your current setup will require some soldering and creativity to make it connect right. However if you want to try this breakout board then you can easily connect your pixels up to the board with minimal / no soldering.

    https://www.tindie.com/products/essenceeng/led-octopus/

    The other question is how are you going to get your light data to the teensy? Serial, Ethernet and or internal effects from fastLED? This will also dictate how you are going to place your teensy(s) and connect them up to your pixels.

  3. #3
    Senior Member crees's Avatar
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    My last Christmas light show I used 6 custom Teensy controllers with a custom breakout boards all ran from xlights/LOR. My farthest pixel was about 15 feet. most were within that range.

    crees

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    My key question is, when using the Octo adapter, how to get the various twisted pairs to where they need to be.

    A few presumptions, please correct me if I'm off base!

    1) I can Daisy chain strips if I want those strips to share an animation.
    2) To avoid excessive drop I will inject power where needed probably at least at each end of the strip if not the middle
    3) The Octo board uses cat6, so I have potentially 8 separate "pin pairs" to carry separate animations, 4 pairs per cable.
    4) Timing is important therefore the shielding on the cable is important.

    So, I'll need to send each cable along a path that touches the end of each separately animated chain of led strips.

    So one cable might start under the deck, run up to the first led strip chain, say on a picture frame window, then continue to the eaves where another led chain runs, then across to say the garage eaves to another led chain, and so on. Now to keep the max shield to the end of that run, the pair that goes to the first led chain will be far from the last chain. The only way I can think to do that is Pierce the shield at the first chain and pull a pair back all the way through the cable and then trim it to be as close to the shield as possible. Then continue this pattern. At the end of the cable, only a single pair will remain in the shield, connected to the 4th led chain.

    Sound right? Other less fiddly approaches for the wiring?

  5. #5
    Senior Member crees's Avatar
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    I tend to dance around peoples answers. I will break my response down directly

    Quote Originally Posted by braddo View Post
    1) I can Daisy chain strips if I want those strips to share an animation.
    Yes on daisy chain. Keep in mind there are limitations! The limitations are Frames perscond / how many pixels are in that string. The other limitation is teensy available memory etc.


    Quote Originally Posted by braddo View Post
    2) To avoid excessive drop I will inject power where needed probably at least at each end of the strip if not the middle
    Correct. you will need to calculate where that injection would need to happen. It will vary with the voltage your dealing with.

    Quote Originally Posted by braddo View Post
    3) The Octo board uses cat6, so I have potentially 8 separate "pin pairs" to carry separate animations, 4 pairs per cable.
    Partially Correct. The octo board has RJ45 Jacks which can commonly take cat5/6. Its board is optimized to use Cat5 or Cat6 cable. The resistors have been added to match the cables impedance. Thus the reason it works well with cat5/6. I have used both with much success.

    Quote Originally Posted by braddo View Post
    4) Timing is important therefore the shielding on the cable is important.
    Correct on Timing, Shielding..... depends

    The pixels NRZ signalling is super critical that any disturbance noise or signal degradation will cause issues. The biggest issue is pixels flickering eratically or not responding at all. Hence my response saying that the pixels NEED to be as close to the teensy as possible. Having a sheilded cable will NOT ensure that you will get your distance at all. Will it improve its chances... Yes Will it solve the distance issue problems... NO.

    Quote Originally Posted by braddo View Post
    So, I'll need to send each cable along a path that touches the end of each separately animated chain of led strips.
    Not sure exactly clear on that question. Each Octo Feed needs to connect to the FIRST pixel of each strip segment you plan to connect. Again AS CLOSE AS POSSIBLE!

    Quote Originally Posted by braddo View Post
    So one cable might start under the deck, run up to the first led strip chain, say on a picture frame window, then continue to the eaves where another led chain runs, then across to say the garage eaves to another led chain, and so on. Now to keep the max shield to the end of that run, the pair that goes to the first led chain will be far from the last chain. The only way I can think to do that is Pierce the shield at the first chain and pull a pair back all the way through the cable and then trim it to be as close to the shield as possible. Then continue this pattern. At the end of the cable, only a single pair will remain in the shield, connected to the 4th led chain.
    Your approach is to send a cable in long segments to your first pixel and hoping maintaining the shielding will allow the signal to carry further. Shielding interestingly can cause more issues than solve. In a perfect scenario it makes sense but realistically you most likely have challenges making it work. Its all because the pixels NRZ signal logic is NOT designed to go distances at ALL! its inherently vulnerable and will undoubtedly have issues the further you go. Improper terminated shielded cable will only add to the problems with this setup as well.

    Quote Originally Posted by braddo View Post
    Sound right? Other less fiddly approaches for the wiring?

    In my book of experience your approach will have challenges. If you can design your setup to accommodate multiple teensies and place them as close as possible to the first pixels of your segments will give you better results than a long shielded cable approach. The question I ask is what do you plan to use or get lighting data to your teensy? that answer will help define your limitations. For instance if you plan to use Ethernet and drive them with artnet or sACN than you can run data to your teensy units easily. If your using USB serial then you will wont be able to run very far from the PC control. If your using fastLED effects or your own LED lighting code directly from the teensy then placing them near your pixel strings shouldn't be a problem.
    Last edited by crees; 12-10-2019 at 05:14 PM.

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    Hey Crees, thanks again for your response. I'm not really sure what you mean by "my approach" since, really what I'm asking for here is what is the typical use for the Teensy and Octo boards for LED animations.

    I'm getting that you suggest that the teensy be as close to each LED strip as possible, and in this case that would mean multiple teensys - but honestly that seems to belie the whole point of the Octo board, which is to drive 8 strips at once from the teensy. It's a big assumption on my part that Paul's design and selection of cat6 was intended to allow the signals to travel longer distances than un-shielded, un-twisted pairs. Otherwise, I don't really understand why the board even exists - if I need to position a teensy (very) near each strip then why get an Octo board, expressly designed to drive 8 strips? I could just solder the wires directly to the strip from the board with a resistor and be done with it.

    I'm not arguing that what I'm suggesting will work, but rather was checking for understanding with the community that what I *think* is the common approach with this board is indeed the case. Maybe someone has tried it and can chime in?

    Meanwhile, you also asked about how I'm driving the animations. At the moment my intention was to just use fastled direclty from the teensy with some hard coded animations that repeat. But in the future it would be cool to attach an esp or raspi mini and use wifi to send over patterns for the board to drive. More code needed for that.

    You mentioned a couple of methods I had not heard of so I will check those out.

    Thanks again, Brad

  7. #7
    Senior Member crees's Avatar
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    All good Brad.

    The octo board is good to get your feet wet and quickly connect to pixels using common easily accessible materials like the cat5/6 cables etc. Its not really intended for long runs etc.

    I have tried it and got 90 feet indoors. Then I moved it out doors and had challenges getting it to run half that. Mostly due to noisy power supplies and the outdoor soldering to the pixels. The way I solved it? Placed my teensy close to the pixels and use the w5500 module to connect the teensy to my data network. I use software like xlights or jinx to drive my boards. check out some of my videos.

    https://www.youtube.com/user/chriswendi/videos

    Note I have been less busy posting my success due to moving my development with a company and designing for their new product (coming online in the next few months)


    You may find that you will have some success going your route. Its hard to say but only one way is to find out and give it a shot. If you run into issues then get more teensy to tackle the job. PM if you run into any issues or post here. I will help out. Just hoping to save you some time with my responses.

    crees.

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    Here's a guy (using the "Falcon Christmas" system - and he seems to be using ethernet for both signal and power (ganging several pairs for power) and gets 30 feet at 30-50% power white.

    I"m not sure if the errors he is seeing are due to voltage drop or signal dropout, but I don't think I need to go more than 20 feet total (not sure yet) in the manner I was describing, and using maybe 14 gauge power wire running along side of the cat6 carrying the signal.

    https://www.youtube.com/watch?v=ko5wu5S0J1o

  9. #9
    Senior Member crees's Avatar
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    Its going to be one of those your mileage will vary. One thing that happens in long runs is the signal logic not only can get noise in the line but also suffer from voltage drop. That voltage drop can can make it difficult for the pixels to discern the NRZ logic. The typical result is pixels not firing correctly with some response. I personally do not see any major issues running ~20ft from the Octo to your pixels using cat6. Shielding will help as long as its not inducing noise into the pairs.

    Off topic you will see some controllers that have long rage over cat5. Those methods use a chip to convert the signals to differential signaling. On the receive end is a receiver card that converts it back to Pixel logic. The differentiated methods can run very long distances (100's feet)

    crees

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    Right, that Falcon Christmas product seems to offer the differential signal lines. I've used that extensively in pro audio, never considered it might be useful for led light shows, but, of course it is... Like every interest, if you look a little deeper you can go off the deep end on the internet!

  11. #11
    Senior Member crees's Avatar
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    Quote Originally Posted by braddo View Post
    Right, that Falcon Christmas product seems to offer the differential signal lines. I've used that extensively in pro audio, never considered it might be useful for led light shows, but, of course it is... Like every interest, if you look a little deeper you can go off the deep end on the internet!
    Yes! I am afraid I ended up somewhere in the deep end.

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