Power Distribution Confusion

[DinoChickenSuit]

Hi all.

I am still working through making my first ever show for this year.

I have a Baldrick 8 controller with a 5v power supply, and around 1200 different 5v WS2811 seeds and bullets.

I am ordering these off of AliExpress, and probably some power distro tees as well.

I just can't understand how I should distribute power. We have a large-ish property (~45m frontage, big yard) which will not all be done programmed, but it seems like, based off of this calculator, I need to inject every 50 pixels? That seems like a lot of power cables going everywhere. And my psu only has two or three spare ports on it.

Am I missing something?
Is there something I need to buy while on AliExpress?
Am I making a mistake buying cheap parts?

 

[RolyT]

imho 50 is probably only required if running at 100% and wanting your full white to be full white. I run plenty of props up to 300 pixels and do a power balance tee at start and end of string and run about 30% and its fine in my eyes. I'm sure others will disagree and that's OK

 

[DinoChickenSuit]

will that look too dim in the middle of a display of normal lights?

(this was our display from last year, the idea is to have the programmed ones going around it)

 

[merryoncherry]

Am I missing something?

The #1 thing people miss is trusting the calculator and not trying it with the stuff they just bought.

I doubt it will be 50 for all the different pixel types you have. Sometimes people mean "each pixel should be within 50 of power" (thus every 100) rather than "every 50". So take the seeds I got a few years ago, at 4" spaced you needed to be every 50 for 4" spacing, within 80 for 2" spacing, and every 100 for 1" spacing, but bullets will be different. And yes, this is based on every pixel on the string being 100% full white without any dimming or discoloration. If you don't have sequences that turn on everything at once, or you dim, this scenario doesn't pop up.

But that spacing is based on most of the 5V being there at the pixels, so a big factor will also be the distance from the power source (say controller) and the prop. If you go from a 5V controller port with a 7.5A fuse down 20m(half way across your yard) of 18CWG standard xConnect extension wire to 250 5V pixels (and add PI wires on the back of it), no, it is not going to work all that well (you'll get 300% voltage drop). You would have to use much bigger wire than 18CWG across the yard, maybe 8AWG. But then bouncing along the string (rather than tying all the way back to a central point) every 50-100 pixels (depending on pixels) would work.

Is there something I need to buy while on AliExpress?

Always.

Am I making a mistake buying cheap parts?

Maybe/maybe not. If you place a high value on your time, and getting cheap pixels with thin wire (for example) leads you to buy a lot of additional wire, tees, PI boards, etc., and spend a lot of time working with it, maybe it was a mistake. If it all works out , you had fun, and people like it, maybe you didn't make a mistake. If you got the Baldrick 8 because it was the cheapest 8-port pixel controller you could find, that wasn't a mistake.

So, I say try it, including the amount of wire for getting from your controller to the prop, based on the yard locations. If things aren't working out there are some easy fixes to try:
Get bigger wire
Move stuff around and put all the pixels close together rather than spreading out over all 45m, maybe have a "pixel corner" with a tree and a face and some other items next to your big AC display.
If you really want pixels all over the yard, get a second controller to cut the cable runs down, support growth, etc.

If you do feel it is a mistake, evaluate 12V, but you'll be out the 1200 pixels (I'm sure you could arrange some sort of a trade).