G'day from Tassie

[Skymaster]

As someone who drilled all my rooflines and window frames, but then used chromatrim for my gutter lines, I wholeheartedly agree with @thewanderingpine 's comment above about time constraints.
Note that I started drilling in April, whenever I had some spare time. It took a fair bit. That was around 480 nodes for windows, and 200 for the roof line

 

[Whitey-]

The value prop is that you don’t need to drill 1300 holes (2600 kindof because it needs to be bigger on one side - step bit helps - but I never get it exact) — and all the holes are correctly spaced and in line for you. And the pixels might be easier to push. Given time constraints you have if you want to get it going this year - it seems like a worthwhile $60 to me.
(Full disclosure - I didn’t use it for my roof outlines and just have drilled conduit. But I’d be tempted by it now I think - and certainly in your case)

That's fair. Maybe I've misunderstood, don't you still need cable tie holes in the conduit? ELD mentions "our preferred 25mm Conduit with cabletie holes", but I couldn't find them on the site. My assumption (maybe incorrectly?) is you drill holes for cable ties, run them through and use the cable ties to connect the chromatrim?

I've just had a look at a few[1][2] posts about this now I understand what I'm looking for, and it appears the ELD site (or my interpretation of it) doesn't marry with reality - it looks like people just run the cable ties around the conduit and through the chromatrim? That makes more sense then, thank you for bearing with me! Looks like $60 well spent.

As someone who drilled all my rooflines and window frames, but then used chromatrim for my gutter lines, I wholeheartedly agree with @thewanderingpine 's comment above about time constraints.
Note that I started drilling in April, whenever I had some spare time. It took a fair bit. That was around 480 nodes for windows, and 200 for the roof line

Thank you! I have a bad habit of assuming I can get things done quicker than I can, which results in a lot of lost sleep . This looks like a very good call.

 

[djgra79]

So you push the pixels into the chromatrine and then attach the chromatrim to conduit for stability. Then the conduit gets attached to the house (roof, windows, wall etc) by using something like cable tie mounts silicone in place or for windows sometimes just pressure fit is enough for some.

As for connectors, yes Ray Wu uses 13.5mm which IS slightly different to Xconnect.

 

[Whitey-]

Thanks @djgra79 ! I saw your posts on roof mounting from earlier this year, that's helpful to understand.

I've just found this thread which probably answers the questions I have now around colourbond roof attachments.

Looks like Light It Up sells 13.5mm pigtails, so I guess I'll see if I can get a bulk pack, ta

 

[Whitey-]

One more thing, it seems browsing around the convention for Chroma characters, candy canes etc is to get them in white rather than black coro. Is there any reason for this? I'd imagine the black blends in better at night, whilst the white would be more reflective and reduce sharpness.

 

[Iain]

On your spacing, you mentioned 2-3 inches, which can make a big difference depending which one you choose. I've found that 3 inches (or 75mm to make my calculations easy) is fine for low-density props - even ones at the street front. No one notices the difference between 75mm and the 3-inch mega-tree strip either.

I've used 2 inches / 62mm for my arches because I want the higher density for the leaping effect. Of course, some even use denser spacing than that.

It's common to make the fencline/front line tighter spaced, and anything further back such as rooflines wider spaced, as the perspective means you need less density as you get further back from the street. That is if you want to save the $.

I reckon you could still get custom lengths in time from Ali, but their prices seem to be higher at this time of year!

Hope that helps!

 

[Skymaster]

One more thing, it seems browsing around the convention for Chroma characters, candy canes etc is to get them in white rather than black coro. Is there any reason for this? I'd imagine the black blends in better at night, whilst the white would be more reflective and reduce sharpness.

I wouldnt say there is a convention on this. It depends on the look you're after, as well as the daytime look. Personally, all my coro is white, but that's because the house is too, and daytime it's not so obvious.
It does provide a bit more colour bleed as you mention, I do like the look of the black in that respect, but keeping the wife and street-look happy was more important in this case

 

[thewanderingpine]

For me - I buy almost all of my coro in white and then spray paint it. My trees are green, Santa’s sleigh is red, reindeer are brown, etc. that’s harder to do on black.

 

[thewanderingpine]

( I need to do better job this year of daytime photos — this was still during setup and testing)

 

[Whitey-]

I've used 2 inches / 62mm for my arches because I want the higher density for the leaping effect. Of course, some even use denser spacing than that.

It's common to make the fencline/front line tighter spaced, and anything further back such as rooflines wider spaced, as the perspective means you need less density as you get further back from the street. That is if you want to save the $.

I reckon you could still get custom lengths in time from Ali, but their prices seem to be higher at this time of year!

Hope that helps!

Thanks Iain! That is very helpful. I've ended up going 2 inch (or thereabouts, 50mm) spacing pretty much everywhere for simplicity and I'm aiming for 1 inch (or 25mmish) spacing on my tree, as my mounting roll is 1 inch spaced - but we'll see how that goes once I start building! I've ordered now (all my pixels are from Light It Up), and run a few hundred short of my estimate needed, as I knew I was overestimating.

I suspect depending on how I do the tree I might need to splice and resolder/heat shrink. I'm not opposed to doing so if the result is how I want, but we'll see how I feel after it's done .

I wouldnt say there is a convention on this. It depends on the look you're after, as well as the daytime look. Personally, all my coro is white, but that's because the house is too, and daytime it's not so obvious.
It does provide a bit more colour bleed as you mention, I do like the look of the black in that respect, but keeping the wife and street-look happy was more important in this case

That makes sense, ta. Yeah I've been poking around and come across a few people who go white and paint them, which seems to be maybe the best compromise point. In fact...

For me - I buy almost all of my coro in white and then spray paint it. My trees are green, Santa’s sleigh is red, reindeer are brown, etc. that’s harder to do on black.

That looks amazing! I've never painted anything in my life (beyond line marking some things in the yard), so I'm super keen to give that a try. Cheers, I've ordered everything in white and (time permitting ) I'll give them a paint!

I'm also now running the 'final version' of my list of anyone's curious. Green's ordered, yellow needs to be ordered, and red I need to work out specifically what/where to source. It's already out of date - I ended up buying T splitters, extension cables, pixel pliers and a tester as well from Light It Up, and I'm sure I'll find quite a few more things I haven't considered - but that's the fun of it, right?

Over the next week or so () I'm going to move from my arduino PoC to an actual ESP32/WLED setup and start fiddling around with the programming, power injection points, 5v -> 3.3v stepping, and all the other fun stuff. Funny story, I ended up browsing the local Reject Shop while I was in a phone meeting and found a couple of cheap solar lanterns for $3 each so I grabbed them, brought them home and ripped them apart to see how they work (1.2v circuit with a cute 200mAH battery), thinking maybe I could chuck in a couple of 18650 batteries, step down and run a couple of WS2811s in the lantern and make them orange.

We've since bought a bunch of random $2 shop halloween junk I plan to light up and set up in the yard before halloween - so we'll see how that goes. A good chance I think to build out some things on a small scale to see how it all works!

 

[thewanderingpine]

(time permitting ) I'll give them a paint!

Remember the (obvious) fact that it's much easier to paint the prop while it's empty of pixels. So if you're going to do it -- you need to paint first.

 

[Iain]

This paint and prime stuff is the best. Water based paint will scratch off PVC easily, even with a sand. Oil based spray such as the cheap “fiddly bits” cans ($5 ea) is good but still scratches a bit. But this stuff is like multiple coats in one. You pay for it though, and they don’t have “hide in the garden green”!

 

[Iain]

One power supply? I'm over-estimating in multiple places, but:

• roughly 48mA per pixel
• 5000 pixels (I think you have?) .048*5000 = 240A
• *5V to get power required = 1200W
• plus 10% headroom if you want full 100% brightness on all pixels at once and leave some space for your PS to smile = 1333W

In reality, pixels probably use a bit less each, power supplies may have the headroom built in to their numbers, and if you use a derating brightness curve (I have a spreadsheet) you don't need all that power either... so depends what you want. But probably more than one.

Also with 5V you'll want to get minimal voltage drop to each prop, so either big thick cables or multiple supplies near a group of props, or both.

 

[Skymaster]

• roughly 48mA per pixel
• 5000 pixels (I think you have?) .048*5000 = 240A
• *5V to get power required = 1200W
• plus 10% headroom if you want full 100% brightness on all pixels at once and leave some space for your PS to smile = 1333W

I really dislike throwing the conversion into watts in there. It adds no benefit to the calculation and starts involving the voltage, which is irrelevant when calculating the power supply size. Work in amps, and use the amp rating from the data sheet of the PSU.
The WS2811 chip is designed to deliver 48mA at full white to an LED, no matter the voltage. This is of course assuming that it is able to (Wire resistances and 'resistor' pixels with too-high resistors will limit this, and therefore derate it accordingly).

One other thing to note as well is that there's a huge mistake made as well in the spreadsheet above - which is the assumption that a Meanwell LRS-350 is a 350W power supply.
That's just the model range, which is typically 350W at the higher voltages. But at 5V, it's only 60A, if you look at the data sheet.
The AliExpress Chinese no-name ones will state they are a 70A PSU explicitly. That said, whether they perform that high is another matter.

 

[thewanderingpine]

It’s also worth noting that the spreadsheet included 5 power boxes - so there is likely enough amps available.