Best practice for joining WS2811 lines

whatthej

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Dec 31, 2019
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Hi all, setting up my first light show. Running fully with WS2811 lines controlled by arduinos. I have a few questions about the layout.

- The left edge of my house is 6m long and I am using a 5m string + 1m that extends from the top edge of my house
- I applied the 4m+1m from the top edge as a poly line (is that best practice?)
- The poly line doesn't seem to give extra dots for the WS2811 config (3 lights/node), the single line shows all lights, but poly lines seem to show nodes only.

What's the best practice for setting up the 5m segments?
 

whatthej

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Dec 31, 2019
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Ok I've managed to find some posts suggesting that poly lines across the whole rooftop is the way to go. My question is now:
- How do I show the correct number of lights instead of nodes only?
- How do I segment the 5m lengths? (Or is that not a layout but completely controller setup)
 

OzAz

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First off, why use Arduino? Use a Pi and a Pi Hat/Cape and you'll get much better control via xLights and FPP :)

Polyline and single line show the same in Layout regarding lights. The only difference with polyline is you can make one continuous line but have it go in different directions.

When you say "5m string" is that pixels/nodes or strip? How many pixels per meter?
Not sure what you mean by "correct number of lights"

Both polyline and single line show 1 'dot' per pixel/node in Layout. So if you have a 100 pixel string you'll see 100 dots. Obviously on your screen they may look very close together.

Here's 2 screenshots, first one shows a polyline with 20 pixels followed by a shorter single line with 50 pixels
second one shows same polyline but with 200 pixels (becasue it's 4 times as long as the short single line)

poly1.jpg

poly2.jpg

As you can see each dot is 1 pixel, but they look a lot closer together than what they may in "real life"
 

whatthej

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Dec 31, 2019
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Hi OzAz, thanks for the details.

WS2811 is 3lights/node. When I set a single string to 3 lights/node * 10nodes/m * 5m, I get 150 lights. But when I set polylines to the same settings, there is no difference whether i set 3lights/node or 1light/node (or 500..). That's what I meant by "correct number of lights"

With regards to the Arduino vs Pi, I'm under the impression that there is no performance difference if we have the right number of universes. I'm able to decentralise a bit more with multiple Arduinos (each controlling 4 strings (5m x 50 nodes), fed from the same power supply). I'm happy to be convinced otherwise though as I haven't shelled out for the arduinos yet (or I can repurpose them)
 

OzAz

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Hi @whatthej I had another look at your issue and it looks like that is a 'bug' in xLights. You are correct that Single Line will display the number of dots (lights) equal to the number of Nodes/String times the number of Lights/Node; whereas it doesn't for Polyline. Never noticed that before, not sure how many people use the Lights/Node setting, I didn't bother with my strip arches.

Perhaps we should clarify some terms as well: :)

As regards to Arduino V Pi it's not about performance but about better compatibility with xLights. Falcon Pi Player (FPP) can be loaded onto a Pi relatively easy and there's no coding required. FPP is relatively easy to setup the type and number of strings and LEDs and can be run Master/Slave, or standalone and also scheduled easily. There are quite a few purpose designed Capes/Hats for the Pi to drive LEDs, DMX, Panels, etc. Pi/FPP can be selected as a Vendor in the new Controllers setup in xLights, and the Capes/Hats as Models.
Just my opinion, hey even Keith one of the xLights devs uses/used Arduino in his display, so what would I know. :laugh:
 

whatthej

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Dec 31, 2019
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Great thanks! Good to know that it wasn't me doing something terribly silly with xLights. With the polyline, if I do a whole circuit around the top of my house - made up physically of 8 strips, how do I represent this:
  • If it's a straight line with 2 strips, do I segment the poly line at the join?
  • I can set individual start channels but I can't seem to define unique channel starts for individual segments
  • I can't seem to individually set starting location [green/blue square] for those strips where it is physically easier to run the start from the opposite direction, how would this be tackled?
 
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