Additional Pixel Strings Won't Light

  • ESP32 Controller on the DigQuad, right now only using LED1
  • Version 0.14.0
  • 5v 60A Power Supply
  • WS2811 Pixel Strings (50 per string)
  • About 20-25’ from board to first pixel (using 18awg 3-wire)
  • Separate parallel power injection from different fuse on the DigQuad at beginning of every string and at very end (using 18awg 2-wire)
  • 4 Strings Hooked together, plus 1 additional (201 pixels total)
  • All joints are soldered/shrink tubed

EVERYTHING SO FAR WORKS GREAT…but…started adding additional strings and ran into problems.

Exiting from pixel 201 → about 12’ of 3-wire → start of new strings (pixels 202 - 751)
Pixels 202-751 are all pre-connected, soldered together prior to connecting to existing strings
Fresh parallel power injection from separate fuse on DigQuad starting at pixel202

THE ISSUE: Nothing will light, starting with pixel 202
Made sure LED1 was set to 751 LED’s (removed the auto 850mAh thing)
Made sure segment was longer than 201 (reset, re-added segments several times)
Checked my power at pixel 401 and I’m still sitting at about 4.7v with the power injection and 4.3v if I take that out of the equation.

First 201 pixels still work perfectly! So this seems to be a problem with my data line.

My guess is that I either have something wrong with my 12’ jumper between the 2 roof lines, or perhaps some thing is wrong with pixel 202. (seems that it would be very coincidental that the very first pixel of that new roof line would be the culprit) I don’t know enough about that data line to know if it would just stop after pixel 201. I was expecting maybe a drop in brightness, or flickering, or something. But they just won’t light up. Is my data line just too long at that point? How do I troubleshoot a data line? Test the voltage? Total noob here. Any advice is appreciated.

Thanks!

If it were too long you would likely have random flickering, not no lights. Likely to be an issue with your splice after 201 or the other end of the splice entering 202

or pixel 201 is bad and not sending data, or 202 is bad not receiving it.

Sounds like a possible power and/or data problem.
In order:
Try to connect the ESP32 directly to string #2. If you can put is as close as possible. Make sure you’re feeding to the Data In pin. That will tell you if there’s an issue with string2.
If string 2 is proven good, try to connect to pixel 201 to see if there maybe an issue with the 202 output.

Your data lines in general are on the longer side, you could also try changing the data cable to something lighter, like 22/4. Feed a separate ground and data wire together from the end of string1 to the start of #2.
Alternatively, the guaranteed fixes are in the KB: Long Data Lines

Testing a data line is tough without an oscilloscope, most people get a small set of known good LEDs and try them at various points in the data line to find where it “drops out”.

Thx for the quick replies. Great troubleshooting steps. I’ll run some tests and report back!

Ok, got this figured out! To test, I used a known good strand and started from the ESP32 then moved my way out. Turns out I had not just a bad pixel, but I think and entirely bad stand of 50. Coincidentally, it WAS the strand starting at pixel 202, right at the end of my jumper between the 2 roof lines! I replaced that entire strand and now I’m in business.
Currently sitting at 417 pixels on LED1 (my stopping point for today). With the parallel power injections, they all appear perfectly bright. Effects also working!!

Thanks so much for the troubleshooting tips!

Nice! Make sure you didn’t hook up that nonworking string backwards.

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