Dear Community,
I'm running out of ideas on how to get our LED-Wall (1200 WS2812B LEDs) to work.
Issue:
- When starting up, everything looks fine.
- After a while (sometimes one minute, sometimes 20-30 minutes) single LEDs drop out (therefore the whole strip). After a longer period, some more drop out.
- Turning everything off and on again, same LEDs have issues
- Turning it on the next day, everything is okay. Different LEDs than the day before start to drop out after a while again.
--> I replaced some misbehaving LEDs, it helps for the moment, but other LEDs start to act weired again.
Have a look at the video, weired behaviour starts at around 0:50 and is obvious from 1:30 on:
https://www.youtube.com/watch?v=0haWijzcMh4
How it's built:
- Teensy 4.1 with the OctoWS2811 example controls four blocks of LEDs (on Pins 28, 29, 30, 31)
- each block has 300 LEDs (6 rows with 50 LEDs each)
- four blocks with 300 LEDs each = 1200 LEDs
- each 50-LED-row gets power from both sides, also a capacitor (100uF 25V) is added on both sides. So each 50-LED-row has two caps.
- Signal cables: a shielded and grounded CAT6-cable goes to a connector at the bottom of the LED Wall, from there a shielded cables goes to each block.
- Logic levels are shiftet with a 74AHCT125N before the signal enters the CAT6-cable.
- The Teensy and the 74AHCT125N run with a separate power supply on 4.8V, the LED Wall power supply is adjusted to 4.9V.
What I think is not the issue:
- Power. I read a lot of power issues, but I don't think/hope that's the problem here. Power supply has 90A, we have two lines with 4 AWG (20mm²) going into both ends of each of the strips. We have stable 5V in "all four corners" and I also could not detect any voltage drops with the oscilloscope.
What could be the issue:
- Simply poor quality of the cheap LEDs, like Paul Stoffregen mentions in several posts. I already replaced around 1% of the LEDs (10 out of 1200), but they keep "dying" (or, well, they live the next day öÖ)
- Overheating? But touching them, they don't get hot at all. They're glued on with hotglue.
- Electromagnetic interferences? I still wonder how this Pixels even work without shielded signal cables. And why would it effect a single LED?
- I'm using the WS2811 library. Would the WS2812B make any difference here?
Code
Simple as it is, it's the example from the library with other pin numbers:
Here also some pictures:
So far, so good/bad. I would highly appreciate any thought and say thanks in advance.
all the best,
clockdiv
I'm running out of ideas on how to get our LED-Wall (1200 WS2812B LEDs) to work.
Issue:
- When starting up, everything looks fine.
- After a while (sometimes one minute, sometimes 20-30 minutes) single LEDs drop out (therefore the whole strip). After a longer period, some more drop out.
- Turning everything off and on again, same LEDs have issues
- Turning it on the next day, everything is okay. Different LEDs than the day before start to drop out after a while again.
--> I replaced some misbehaving LEDs, it helps for the moment, but other LEDs start to act weired again.
Have a look at the video, weired behaviour starts at around 0:50 and is obvious from 1:30 on:
https://www.youtube.com/watch?v=0haWijzcMh4
How it's built:
- Teensy 4.1 with the OctoWS2811 example controls four blocks of LEDs (on Pins 28, 29, 30, 31)
- each block has 300 LEDs (6 rows with 50 LEDs each)
- four blocks with 300 LEDs each = 1200 LEDs
- each 50-LED-row gets power from both sides, also a capacitor (100uF 25V) is added on both sides. So each 50-LED-row has two caps.
- Signal cables: a shielded and grounded CAT6-cable goes to a connector at the bottom of the LED Wall, from there a shielded cables goes to each block.
- Logic levels are shiftet with a 74AHCT125N before the signal enters the CAT6-cable.
- The Teensy and the 74AHCT125N run with a separate power supply on 4.8V, the LED Wall power supply is adjusted to 4.9V.
What I think is not the issue:
- Power. I read a lot of power issues, but I don't think/hope that's the problem here. Power supply has 90A, we have two lines with 4 AWG (20mm²) going into both ends of each of the strips. We have stable 5V in "all four corners" and I also could not detect any voltage drops with the oscilloscope.
What could be the issue:
- Simply poor quality of the cheap LEDs, like Paul Stoffregen mentions in several posts. I already replaced around 1% of the LEDs (10 out of 1200), but they keep "dying" (or, well, they live the next day öÖ)
- Overheating? But touching them, they don't get hot at all. They're glued on with hotglue.
- Electromagnetic interferences? I still wonder how this Pixels even work without shielded signal cables. And why would it effect a single LED?
- I'm using the WS2811 library. Would the WS2812B make any difference here?
Code
Simple as it is, it's the example from the library with other pin numbers:
Code:
#include <OctoWS2811.h>
const int numPins = 4;
byte pinList[numPins] = {28, 29, 30, 31};
const int ledsPerStrip = 300;
DMAMEM int displayMemory[ledsPerStrip * numPins * 3 / 4];
int drawingMemory[ledsPerStrip * numPins * 3 / 4];
const int config = WS2811_GRB | WS2811_800kHz;
OctoWS2811 leds(ledsPerStrip, displayMemory, drawingMemory, config, numPins, pinList);
void setup() {
leds.begin();
}
#define RED 0xFF0000
#define GREEN 0x00FF00
#define BLUE 0x0000FF
#define YELLOW 0xFFFF00
#define PINK 0xFF1088
#define ORANGE 0xE05800
#define WHITE 0xFFFFFF
#define BLACK 0x000000
void loop() {
int microsec = 2000000 / leds.numPixels(); // change them all in 2 seconds
colorWipe(RED, microsec);
colorWipe(GREEN, microsec);
colorWipe(BLUE, microsec);
colorWipe(YELLOW, microsec);
colorWipe(PINK, microsec);
colorWipe(ORANGE, microsec);
colorWipe(WHITE, microsec);
}
void colorWipe(int color, int wait)
{
for (int i = 0; i < leds.numPixels(); i++) {
leds.setPixel(i, color);
leds.show();
delayMicroseconds(wait);
}
}
Here also some pictures:
So far, so good/bad. I would highly appreciate any thought and say thanks in advance.
all the best,
clockdiv