I hope someone may have a resolution for this. Here's my setup:
I have 8 16' 150 led WS2812 light strips controlled from 4 digital outputs (pins 4, 5, 6, 7).
I'm using two 5vdc output 300 watt power supplies with the 5vdc commons and the ground from the Mega2560 board shared.
I have the Mega2560 board powered separately by a plug in 5vdc power supply.
The led strips are daisy chained in 2's making 4 300 led strips.
I have a separate 18-2 cable from the power supplies going directly to the second strip of each pair of led strips to inject 5vdc directly.
The strips are attached to 4 PVC hoops over my driveway spaced 10' apart.
My control box (2560 board, power supplies, etc.) is in between the middle two hoops to keep all the cables as short as possible. I'm using 18-3 shielded cable to get from the control box to the first strip on each hoop.
I think that describes my configuration ok. The problem I'm having is that if I try to run all four hoops I get leds lighting up at the brightness I want but they seem to not be getting any control data from the board. If I change my sketch to only drive the two center hoops (shortest cable length) they work fine. If I try to drive either outside hoop (longest cable length), regardless of what pin i try to drive them off of they partially light up (not dim, just misc leds) but don't control at all. I had the 330ohm resistors inline on the data wire on all four. I took the resistors out of the two outside ones and the problem reduced slightly, I was able to get some control but it was very slow compared to the center hoops.
I'm pretty confident that it's the cable length causing the problem (excessive resistance over distance) which would be easy to fix if it were the 5vdc power and not the data loop.
This all being said, is there a way to boost the data loop signal or can someone recommend a different kind of wire that may have less resistance? This is a Xmas display so any help would be greatly appreciated.
P.S. All eight strips worked fine bench testing, all that is different is the length of the wire to them now.