I've been trying to use WS2815 leds in my stairs, but I'm struggling with noises problem.

I'm using stm32f103c8t6 based bluepill board as a controller for 18 1m long led strips. Each strip is controlled separately, using TXS0108E level shifters. Between each pin and led strip there is ~4 meters of 0,35m^2 wire. I've created a board to place all components but there was a a problem with wire capacity, which I solved adding 4k7 pull-ups (green lines) and 100nF capacitors (pink lines). The last problem I cannot overcome are noises (or some capacity, making line unable to go LOW). The problem is, that first pin from power source (first from right) works perfectly, second has a little noise and every next one is worse. Should I use other resistor for pull-up? Or maybe use pull-down instead? Problem does not occur if I connect led strip straight to the board, without the long wire.


  • \$\begingroup\$ You lay out the +5V line in a way I would call the almost worse possible according to my experience: It goes in a snail shell fashion around the board which leads to serious drop of voltage for very "outlet". better use a "star" like layout for power lines. Furthermore is routing over a pad dangerous e.g. if the pad gets ripped up during soldering/mechanical loading. Last but not least your ground plain is severed in many islands which are hardly interconnected. Do you need to stick with one layer? Do you need to avoid VIAs? \$\endgroup\$ May 21 '20 at 9:51
  • \$\begingroup\$ Yes, it has to be one layer. I may make power lines a little bit thicker, make some connections between ground islands using 0,5m^2 wire. \$\endgroup\$
    – K K
    May 22 '20 at 7:27

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