Splicing CCR2 bulb strings

[alodine]

So - I have several trees. I want to run CCR2 bulbs up each major branch. I want to cut off part of the 50 bulbs and splice them back on the starting end of the string. What that gives me is a 'Y' that works perfectly to go up 2 separate branches rather than having to double back on one branch before reaching the next branch.

If (this is an assumption) the three wires connecting each bulb are a continuous bus all the way to the end, this should work. The original portion of the bulb string will have their addresses unchanged. The spliced on portion address will start at wherever they were spliced from. This will complicate the programing but I am up to the task.

On the other hand, if the chip in each bulb somehow depends on its previous chip to operate correctly, this scheme would probably not work.

Anybody ever tried this?

 

BTW - I have no problem splicing and waterproofing the wires. Have done this many times with other projects.

[Mr. P]

You can't branch or split pixels as they are not actually individually addressed themselves. Pixels are addressed according to the order that  the signal gets to them. Pixels are linear and unidirectional, there is no way around that.

[Jimehc]

make an Extension to go from top of string to bottom of next string - then create as a "Custom" prop...

Or do a test, Since, "Pixels are linear and unidirectional", if you were to put a "Y" in the string - you might find that both "Branches" would react the same

Edited May 25, 2022 by Jimehc

[Mr. P]

36 minutes ago, Jimehc said:

Or do a test, Since, "Pixels are linear and unidirectional", if you were to put a "Y" in the string - you might find that both "Branches" would react the same

I did that back in 2015-2016 when pixels first started becoming popular. I did a run of 25 pixels and then a Y of 25 in each branch starting at pixel 26. I was thinking I would have two 26's, two 27's and so on. The pixels lit as expected up to pixel 25 then they became random with random lighting and random colors from pixel 26-50 as if they were confused. Was it the protocols? Was it the number of pixels? Was it the Y? I don't know.

[alodine]

OK -

Thanks to all who responded. Looks like it won't work.

Thought the three wires were RS-485 and each chip on a particular light just responded to its own address. But that scheme would require at least one more wire for power/ground. Sounds like the chips intercept the traffic and modify the signal on the way out of its chip.  A puzzlement.

 

[k6ccc]

The three wires are power, ground, and data.  Power and ground are straight forward.  Data comes out of the controller with a string of data for all the pixels in the string.  There is no addressing.  Each pixel thinks it is the first pixel in the string.  It receives data for all the pixels, processes light level for the first pixel and regenerates the the remaining pixels worth of data and sends that to the next pixel.  In other words, on a 50 pixel string, the controller sends 50 pixels worth of data.  The first pixel receives 50 pixels worth of data and processes the data for the first pixel.  It then regenerates the data for the remaining 49 pixels (not sending the data that it used for itself).  Pixel 2 repeats the process.  By the time you get to the last pixel, there is only one pixel worth of data being received.

Back to the original question, yes, you CAN split a string - sort of.  Using Mr. P's example of 25 pixels and then split it into two branches.  That should work with a caveat.  What that would end up with is the data for each pixel after 25 will show up twice - once on each branch.  Depending on what you are doing, that may look fine - and maybe not.  The caveat (and what I suspect Mr. P ran into) is that unlike the controllers that more umph to send data, and the pixels have very little.  They are designed around the concept that the next pixel is pretty close and can't drive much of a load (such as multiple pixels).  Several years ago I did a test with a SanDevices E682 controller and had multiple strings of pixels connected to the one output.  The pixels strings were only a few inches from the controller output.  Four pixel strings worked reliably, five mostly and six strings was too much and largely did not work.  Splitting a string as is being discussed here means that a pixel chip is having to drive multiple pixels and they are very limited in their ability to do so.  In other words, it MIGHT work depending on your exact situation.  Test fully.

 

[Mr. P]

I don't know if this makes any difference but when I first started pixels I was using WS2801 which is a four wire with a clock wire. Plus, pixels back then could only go 10-12 feet. Now pixels can go a mile it seems like.  😄

Edited May 25, 2022 by Mr. P

[alodine]

Tnx K6ccc for the info. BTW- WB6nvd here.

So - a better way for my use would be to cut between two bulbs and add an extension to thread back down to the trunk and re-connect the cut-off bulbs. As long as the solder joints are good and the extension is not too long, the entire string should work as programmed.

Is this scheme following any standard I could study? Do you happen to know if the power & ground are the two outer wires with the data signal in between?

[Mr. P]

1 hour ago, alodine said:

Tnx K6ccc for the info. BTW- WB6nvd here.

So - a better way for my use would be to cut between two bulbs and add an extension to thread back down to the trunk and re-connect the cut-off bulbs. As long as the solder joints are good and the extension is not too long, the entire string should work as programmed.

Is this scheme following any standard I could study? Do you happen to know if the power & ground are the two outer wires with the data signal in between?

Pixels are all wired differently. You can actually look at the little board inside the pixel and it will be printed on the board which wire is which. There will also be an arrow printed on the board showing the direction of data. I use some cheap magnifying glasses to help read the boards.

[alodine]

Tnx Mr.P

I got out my mag glass and yes, I can see the info I need.

Thanks all for the help.

[Box on Rails]

If you are using LOR Pixel strings you might take a look at this page on extension length.  https://www1.lightorama.com/pixel-extensions/

This has an explanation on how LOR pixel wires are marked on page 4 and 5.  https://www1.lightorama.com/PDF/ConnectingPixelsToPixelControllers.pdf

 

[alodine]

Hello

 

Thanks for the info.  I had seen the second page.  The first one answers a lot of questions now.

Nice to have experts available.