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I'm working on a project involving a bunch of daisy-chained WS2811 lights and I'm noticing significant flickering on the ones at the end (lights #16-30 in a chain of 30).

Right now, the circuit is a 3.7V lithium ion battery connected to both a 3.3V Gemma Arduino and also in parallel to the lights. I'm using thick 16 AWG stranded wire to run big "central lines" for power and ground and then soldering smaller 22 AWG wire from those central lines to the individual LEDs. At peak, the longest cable run is about 4 feet from the battery to an LED.

The data lines are obviously daisy chained to each other, and I have a 330 Ohm resistor between the data line and the first LED as recommended by Adafruit.

Here's a video of the flickering.

Any idea what might be going on or how I should debug this?

Thanks!

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  • \$\begingroup\$ What is the supply voltage at the end? \$\endgroup\$ – Ignacio Vazquez-Abrams Jun 23 '15 at 4:24
  • \$\begingroup\$ I just checked and my multimeter read 3.73 volts at the end of the chain \$\endgroup\$ – user358829 Jun 23 '15 at 5:46
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It turns out that WS281X reshapes the signal on output, therefore the timing of the bits has to be reasonably tight otherwise a reset signal may be generated within the pulse train by further devices. Verify your code to make sure that the pixel timing is as expected by them.

"NeoPixels Revealed: Why you should give your bits room to breathe"

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  • \$\begingroup\$ Or use a newer, less time sensitive led driver. \$\endgroup\$ – Passerby Jun 30 '15 at 15:44
  • \$\begingroup\$ The thing about WS2812/B LEDs is that the driver is contained within the LED package itself, so swapping it out is not possible. \$\endgroup\$ – Ignacio Vazquez-Abrams Jun 30 '15 at 15:57
  • \$\begingroup\$ Too late to edit. Use a newer led + driver combo :D \$\endgroup\$ – Passerby Jun 30 '15 at 16:10

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