12" or 18" separation between pixels?

art_light

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Hi all,

I'm wondering if anyone has ordered 12V strings with, say, 12" or 18" of separation between the pixels, rather than 4". I'm thinking of embedding lights into shrubbery and up onto my trees, but need it to be only sparse, for a light twinkling effect, rather than a primary display. Mostly ambiance. Then I'll use my 4" strings for the main show.

Has anyone tried this? How did it look? And what kind of affect on performance might I expect (voltage drop, etc.)?

Thanks very much?
 

AAH

I love blinky lights :)
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The voltage drop is going to be massive if you're looking at going 3-4 times as far between pixels. This would be an ideal job for GS8208 pixels as they are 12V but only 1/3 of the current of WS2811.
 

i13

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I have some 5V WS2811 pixels that are spaced approximately 19 cm (7.5 inches) apart and the voltage drop is much more than the standard spacing. Their wires aren't all that thick. With your spacing, it would definitely be worth asking for pixels with 18 AWG wire and you're likely to need power injection. Turning the brightness down should help too.

I like the effect that I achieved with the wider spacing. I bunched one end of the strands together at the base of a tree and hung the other ends in the branches so that they spread out. I modelled it as an upside-down 2D mega tree.

Although voltage drop might be even worse, the 3 wire pixel in this thread comes to mind. I haven't tried these and I don't own any but I think they'd give the effect that you're aiming for. Some comments mentioned that they might not last in the weather. https://auschristmaslighting.com/threads/13341/
 

TerryK

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... look? And what kind of affect on performance might I expect (voltage drop, etc.)?

Thanks very much?
Should not affect performance other than increased voltage drop as already mentioned by other posts that would not be properly managed. I would suggest using regulated pixels as they are more immune to voltage drop and then plan on managing power injection more closely than typical. Also suggest 18 AWG wire or heavier and probably keep the string length at 50 pixels to keep the 'tangles' smaller.
 
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art_light

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Super helpful, everyone, thanks. So it sounds like 18 AWG, 12V, 50-pixel-max, might work...if I stick with WS2811. I'll do more reading about GS8208, as you suggested AAH--from my quick search, seems like they could be a good successor to 2811 anyway, is that fair to say?
 

TerryK

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The GS8208 and WS2815 are similar in operation in that the RGB LEDs are series-ed with a unique switching scheme resulting in a low amperage pixel. Because the LEDs are in series and their Vf (Forward Voltage drop) they are 12 Volt devices, or at least they are so far (never say never). The WS2815 is a LED/IC package so the WS2815s are strip. AliExpress has GS8208 as strings or strip but as a GS8208 is also a LED/IC package their string is rather 'different'.

I have several strips of the WS2815s, just toying with them, none actually in any props yet. Other than the string versus strip debate, I have noticed that the pixel divergence angle is narrower on a strip (light intensity drops quicker with side viewing). Logical because of the diffusing dome design of a WS2811 pixel LED which a WS2815 does not have.
 

art_light

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Thanks Terry. As far as you know, are the usual control boards able to drive the GS8208s? I have an F16V3, and the specifications don't explicitly call them out (or the 2815s) as supported. I don't see much traction for them yet on the Falcon forums. Perhaps I should have looked more closely at AAH's offerings before I dove in. :)

Again, thanks for the tips.
 

Srmorgan

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I did my entire roofline last year with 12v, 8” spacing, resistor pixels and only one injection point. I think it measured about 130’ and it looked great. I did run it at 30% but it also looked good testing it at 100%. So I’d imagine that your idea should work as long as your not going to extremes with it.
 
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art_light

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Thanks Srmorgan--that's good to know.

BTW, newbie question: is the concern about voltage drop due to the distance between each pixel, or the entire length of the string? My initial understanding is that it is both, is that right?
 

algerdes

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The real cost of voltage drop comes from 4 things: 1) wire diameter, 2) number of solder connections, 3) number of devices using that power, and 4) overall length of the wire. For most here, it is wire size and length. Distance between pixels will affect the control signal (and its associated "ground/return"") more than anything else. At 18" or less, there should be no problem as each pixel regenerates the signal. FYI - solder connections rates last as a problem, unless you get some bad joints.
 

TerryK

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Those 2 variables alone? I would say string length. But then string length is pixels spacing and the number of pixels. Even if the pixel spacing on the string was not fixed the voltage drop over the length would have more attention as the length consideration indirectly forces pixel quantity into the equation.

With a practical perspective, voltage drop needs managed from the supply to the pixel furthest from the supply in a manner that gives that furthest pixel the voltage it needs to correctly illuminate based on how it is being commanded.
 
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