New to this but have a wiring question

Srmorgan

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Jan 26, 2020
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Hello everyone. This will be my first year attempting to decorate the house with RGB LED’s. I am really excited to jump in but have a question I am not sure the answer to. Is it possible to take a run of lights that goes along the roof of the house and split it into 2 runs? One to go up the side of roof and the second to go down the side of the house. I plan on getting a falcon f16v3 and using xlights.
 

Katekate

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Jan 1, 2020
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not sure exactly what you mean, but for every possble thing I could conceive that you are trying to convey, the answer is yes.
 

Mark_M

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If this is for running pixels the answer is no, for dumb RGB then its a maybe.

E.g.
You send 510 channels of data to a string of pixels.
The first one receives the 510 channels, takes it's 3 channels and passes the 507 channels to the next.

Now imagine that pixel node (bulb) 1 got the colour red, the 2nd node got the colour green and the 3rd gets the colour blue. But that 3rd one has the extra pixel spliced into it. Both those pixels which are technically node 3 and get the same colour for blue.


pixelDataFlow.PNG
In reality of splitting the run there is bound to be some issues with the signal getting mangled.

You'll need to have the end of roof line continue up the roof side and then have another cable from the F16 for the side of the house.

For dumb RGB it's just power, all lights are the same colour, so it doesn't matter. But you may need some sort of power amplifier.

Attach a photo would be nice :).
 

djgra79

My name is Graham & I love flashing lights!
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Pixel data needs to flow in one direction and traditionally (I beleive) can't be Y split. To acheive different runs on your roof however, just use 2 or more outputs from your controller as required.
Below is an example of how I did my roofline. It uses 3 outputs, 2 fed from left hand sie of roof (one starts at gutters, one starts top of roof) and one from left side.
Power injection is shared 50/50 left and right from 2 different PSUs that has +pos broken (not joined) between them, but the negatives are, as data uses this as a reference.
View media item 1148
 

roy

the confused elf
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Apr 25, 2019
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Mickleham, Victoria
exactly as Graham says, you would create two seperate connections from your controller... and use xlights to set up, else if the two runs are close and the number of lights per run is not too much you could daisy chain them. The signal runs serially so you can not split the signal from one port to run two RGB pixel strings in parallel .
 

Srmorgan

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Jan 26, 2020
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Thank you so much. That’s what I thought, but there is so much information to absorb its a little information overload. I was also thinking about creating ice cycles on the roof line by doing that. So I guess I will have to run from the roof down to the bottom of the ice cycle then back up and set it up in xlights. Sorry I don’t have any pictures yet.
 
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TerryK

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Feb 9, 2020
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West Central Ohio
An interesting question. I have considered doing just this and feel it is possible. My thoughts if I may...

The answer in my opinion is somewhere between Kate and Mark. Mark's diagram should work providing the ICs are identical and the 'Y' lengths are the same or nearly so. This is due I think mostly to data signal reflections in the Data line and to keep the 2 downline strings from corrupting each others data. As Mark indicates the nodes on the downline opposed strings should syncronize so if you mount one up a corner and the other down you will have a 'zigzag' effect.
The iffy part is; I've already looked through WorldSemi's spec sheet for several of their ICs and the specs do not indicate input loading or output capacity of their ICs. The specs seem to indicate they are CMOS in design so one IC should be able to drive several downstream ICs but without testing there is no easy way to determine that. Power injection will also need to be done carefully, that is at the same or near exact placement in the opposed strings to minimize power injection back around and into the opposed string.

I likely missed something but this is longer than I anticipated and a bit more technical as well; no offense intended. To answer your question, possible: yes; practical, probably not. It is I think less complex and more reliable to use separate strings and let the software handle any synchronizing.
 
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