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Thread: cat 5 for data -

  1. #1
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    cat 5 for data -

    An interesting discussion a few years old (https://diychristmas.org/vb1/showthr...conductor-wire) made me wonder about the proper way to use cat 5 for data. I asked for clarifications there. MrGrumpy responded and asked details about my setup, so rather than hijacking that thread, I decided to repost here with this new thread.

    Quote Originally Posted by Jchuchla View Post
    with regard to the bigger wire, remember, bigger wire = bigger room = more echo. Ideally the wire will be as small as possible while still delivering the required data voltages at the far end.
    Never double the data line. Double the power and ground, but use a single wire for data. Doubling the data line is just like making one long tee cable. It makes for really nasty reflections.
    A null pixel is a regular pixel like any other. the controller will always send an extra pixel's worth of data all set to zero for each null pixel it's configured to have. The null pixel still consumes the first 3 channels and passes the rest on to the next pixel. This works because it keeps the data line of each segment short and therefore gives each hop less wire to get messed up on.
    there's also the buffer boards out there such as robG's design. These give the benefits of a null pixel without consuming any data or requiring any setup on the controller. Basically this board takes in the whole data stream, and then outputs a fresh clean version of that same whole data stream.
    I was thinking or running ground and data (no power) using cat5 cable. I was going to combine solid colors together and color striped wires together, run ground through 1 set of 4 combined wires together (let's say solid colors), and data through the other sets of 4 wires together (let's say striped colors). I thought this is what people were doing until I ran into this thread. Is it to be understood that only 1 wire out of the 8 available in cat5 should be used for data, and the 7 other ones then used for ground?

    On a side note, I am planning on using power using landscape wire (16 ga). I initially was also going to use landscape wire to run data and ground when I found some cat5 I got a few years ago but never used... would landscape cable be a bad idea for data?

    Thanks in advance for your recommendations.

    Quote Originally Posted by mrGrumpy View Post
    I would like to know the load and distance to help to answer best for the application.

    Side note: Data likes to be twisted around a ground (v-) wire, therefore cat5 is a better choice, but your current loading may require 2 (or more) runs of cat 5 in Parallel.

    Edit: yes, only 1 data lead, even if you run more than one cat5.

    I am daisy chaining 6 candy canes with 50 pixels (48 actually) 2811 each at 5V:

    current draw each: 0.02A X 3 X 50 = 3A
    current draw total: 6 strings X 3 = 18A
    Power total: 5V x 18 = 90W

    Using a 24V main power supply and a power buck at each of the candy canes (total 6 power bucks)

    Distance: Wire length between each candy cane: 6 ft
    Total distance between 1 and last candy cane: 30 ft

    I did make the first connection for data between candy cane 1 and candy cane 2 using landscape cable and it works fine. But if cat 5 is recommended, I will do the remaining connections for data using cat 5 and keep my landscape cable for power injection only.

    Again, thank you for the suggestions you may have.

  2. #2
    Old Man Winter member
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    You have it correct. Only one wire of the eight is needed for the data + feed. In fact, using more than one wire causes some things that may or may not happen in your situation, and I don't have my notes here to put down what some of those problems could be. A single wire for data + is sufficient.

    Using the bonded (combined) ground is not a problem, but if you are not going to push power down the other three, there is no need for that either.

    In essence, for data you only need one pair.

  3. #3
    Frosty member mrGrumpy's Avatar
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    90W @ 24V is 4A.....each cat5, 24 gauge is 2A, so maybe look at cat5 1-data 4-Grd and 3-24V. (pair data with a ground)
    The buck units will draw some load so I would run reduced brightness (you’ll not notice the reduction.) Shelby’s latest beta release has brightness control for ESPixelSticks - I tested beta over 4th. Worked without issues for my needs.
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    Quote Originally Posted by algerdes View Post
    You have it correct. Only one wire of the eight is needed for the data + feed. In fact, using more than one wire causes some things that may or may not happen in your situation, and I don't have my notes here to put down what some of those problems could be. A single wire for data + is sufficient.

    Using the bonded (combined) ground is not a problem, but if you are not going to push power down the other three, there is no need for that either.

    In essence, for data you only need one pair.
    Thanks for the reply. Would the following be correct then, or am I misinterpreting your comment? data only needs 1 wire but since data needs ground to be run at the same time, effectively 1 pair of wires from cat5 is needed (usually orange pair), one for data, the other for ground. So technically 2 of the 8 wires of cat5 will be used, leaving the remaining 6 for power (and ground).

    Quote Originally Posted by mrGrumpy View Post
    90W @ 24V is 4A.....each cat5, 24 gauge is 2A, so maybe look at cat5 1-data 4-Grd and 3-24V. (pair data with a ground)
    The buck units will draw some load so I would run reduced brightness (you’ll not notice the reduction.) Shelby’s latest beta release has brightness control for ESPixelSticks - I tested beta over 4th. Worked without issues for my needs.
    Thanks for the information and suggestions.
    I have not used the beta release, I'll have to check it out, the brightness control could be handy.
    My setup does not use cat5 for power and I am only using it for data transmission. Sort of a pity to have 8 wires and only use 1 (or 2) for data... The power bucks are only good for 2.5-3 amps max so after 50 pixels, I need another power buck. I was trying to push power from one string to another but the recommendation was to separate the +V lines (set up can be seen here: https://diychristmas.org/vb1/showthr...035#post107035). Now if I lower the brightness, that might be a different story.

    So is there an easy to find and affordable 2 wire cable that would be good to use for data transmission only then? I tried one length (6') using landscape cable and it worked fine. I have not tried multiple in series yet... and running a 16 ga for data might not be the best price/performance combination.

    Thanks again for the help.

  5. #5
    Frosty member mrGrumpy's Avatar
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    Not sure why you are looking to use 16 gauge wire. Appears to be a 4-5A load @ 24V, and 16 gauge is rated about 12A.....plus you are undersized with a 5A fuse. You will likely get nuisance fuse blowing at 5A fusing

    I go back to the cat5. If you are going to run it for data, than use it for power too. 24 gauge copper is 2A, three would be 6A. Your load is 4-5A. No need to run more wire than the Cat5........and consider fusing at 8A or 10A
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  6. #6
    Old Man Winter member
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    Quick answer - yes - 1 pair for data.
    The ground of that pair can be shared with the VDC ground, but is not a strict requirement. Somewhere it is always a good thing to combine DC grounds. If you are not going to put power down the other three pairs, then only one pair of the comm cable is required for E1.31. (Jon's notes, as others, say the same thing.)

  7. #7
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    Thank you for mrGrumpy and algerdes for your help and comments.

    I am rethinking the approach for this set of props. Use of landscape cable was more about using what I have around than anything else, when I discovered I had some unused Cat 5 (but I may not have enough as I need some for a flood light I am adding to my display and want to maintain the wiring concept I used for the others).

    mrGrumpy, you comment about fusing made me wonder about how to fuse that system. I might come back with questions on that matter.

    Thank you again for the feedback.

  8. #8
    Frosty member mrGrumpy's Avatar
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    When reviewing your fuse sizing, the rule are to find your load. Multiply by 1.25, then round up to the next available fuse.
    Example: if using ATM fuses with a load of 4.10A, then 4.10 X 1.25 = 5.13A so round to the 7.5A fuse.

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