Power injection - still flickering with multiple psus

Toni

New elf
Joined
Aug 31, 2018
Messages
33
Location
Sydney
Hi all,

Couple questions

I'm running 20m strand of 5v WS2811 @ 22cm spacing = 92 nodes total. No extension lead.

The last 10 meters, especially the last 5m is flickering so I obviously need to power inject.

With the positive disconnected in the middle of the strand at 10m - I've tried power injecting at 10m and then tried at the very end of 20m and the flickering is actually far worse, almost like its struggling with data / maintaining the programmed pattern. Thinking that perhaps the data line in the middle of the strand was the issue I rewired it again and again. Still same problem.

I've worked out that i need at least 5.52A (Number of pixels x 0.06)

1.png

2.png

Questions:

The fact im using two 3A PSUs could be the problem? Do I need two PSUs higher than 5.52A? Does 2x 3A PSUs not equal 6A?

I was told that there's a certain side of the pixel node that can only take power. Is this true? I've tried powering from both sides and it appears to work.


Cheers
 

burnt

Full time elf
Joined
Nov 17, 2014
Messages
121
can you take some voltage measurement. at psu and end of + with full white and one colour.
 

bxsl

New elf
Joined
Nov 9, 2019
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9
Do you have a FM transmitter? I had some problems this year with the FM causing interference on some strands, had to move Transmitter
 

AAH

I love blinky lights :)
Community project designer
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Dec 27, 2010
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Eaglehawk
Voltage measurements at the start, middle and end would be good to see as an indication of voltage drop problems.
Adding some heavier cable from the start to the end of the 10m sections will help to alleviate voltage drop.
Is the flickering beginning at the same point all the time or is it brightness of pixels dependent?
 

ICon

New elf
Joined
Dec 27, 2018
Messages
26
Is it always the same pixel the problem starts at?

Double check that your earth (-ve) line has a good connection along the string, as the Data signal is relative to earth this can look like a data line issue.

Yes you can feed power in either direction.
 

Toni

New elf
Joined
Aug 31, 2018
Messages
33
Location
Sydney
Powering the pixels directly from the start instead of via the Arduino appears have dramatically improved things.

Still a very small flicker at 100% white though
 
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