Flickering on both parallel 2nd panels of chains

1

Hi,

I’m having an issue where the second panel of both chains that I have, have some flickering/artifacting going on.

My setup:
Raspberry Pi 4B 8GB
Electrodragon v1 or v2 drive board
(4) Adafruit 64x32 4mm Panels
40A 5V Power Supply

When running the 2x2 panel setup (2 parallel chains of 2), the second panel on each chain has some flickering as well as some artifacting on the nearby pixels. There’s also one spot on the end that always shows some red flickering.

My flags used:

--led-cols=64
--led-chain=2
--led-parallel=2
--led-slowdown-gpio=4 (tested all of these and 4 is the only one that displays properly)
--led-pixel-mapper=Rotate:180 (I have it rotated as I'm testing on a bench and am too lazy to flip everything around :P)
--led-show-refresh (program runs at a pretty consistent 200Hz)

I’ve run multiple scoreboard codes (NHL, MLB, NFL) from Github and they all show this same issue.

I’ve also changed out the display driver board with multiple ones of v1 as well as v2.
I also soldered the pins for E-Line to test, and tried the E>4/8>GND as well as E>8/4>GND which in both cases made the problem worse.

I’ve swapped the panels around in different areas and the problem doesn’t follow the panel, but stays consistent no matter what I change around.

IMG_E2016
IMG_E20161920×1439 362 KB

It seems to be something that is not hardware related, but I can’t figure this out.

Thanks for any help!

2

Video of the panels in action (Dropbox)

5

random guesses:
is there any chance it could be poor quality cables?
Have you made sure your power injection is good on all panels?

6

Thought I had closed this out. Must have been in the repository. Turns out that having my voltage output at 5v exactly didn’t allow the panels to have enough voltage, so I was able to overcome it by adjusting to 5.5v. Everything has been good after that.

7

Only the lower half of the two right panes seem to have a strange phenomenon.
As @marcmerlin said, low-quality cables can make a lot of electrical noise and degrade the display quality. There is also a way to reduce noise by twisting the + and - wires of the power cable.
One more check points.
Are your led pannels in 1/32 multiplexing mode?

8

Cool, glad that you got it resolved with a bit extra voltage. Weird that you got so much voltage drop, maybe the power wires have an issue?
You can use a multimeter to see what voltage is at power connector of the panel and if you are using the thick power cable, maybe something is wrong with it.