Last LEDs on WS2812B strip flicker slightly Hello FastLED users! I finished my project

Last LEDs on WS2812B strip flicker slightly

Hello FastLED users!

I finished my project containing 200 Leds on a WS2812B strip. Unfortunately I am having some problems powering my project. So far I have my 5V 10A power supply connected on one end and then two cables connecting both ends (GND and +5V). I only get around 3.8V at the end. Can this be the reason for flickering? The first LEDs on the strip don’t flicker at all. Furthermore the last LEDs are a little dimmer/yellow compared to the first ones.

Do you guys have any tips on how I could improve my lightstrip? I am using an ESP8266.


What size wires have you run between the ends? Usually low voltage results in LEDs shifting to red, not flickering. What kind of patterns are you running? Are you using a level shifter? How long are the wires from the ESP8266 to the first LED?

It does sound like a voltage/power issue. Have you tried turning the brightness down? If that solves the problem, then it’s definitely voltage/power. If you’ve got a multimeter check how many Amps the power supply is producing…

Maybe the wires you are using to run power to the far end aren’t large enough?
Also, confirm that your power supply is indeed putting out 5V to begin with.

@Jason_Coon I am not sure of the size but it’s a strand of an old serial cable. I can confirm the red shift when lighting up the color with a constant white color. Even then it flickers slightly even though it shouldn’t actually change at all. I have to note here that my program executes every 10ms even when only displaying a constant color like white in this case. So the flickering could be caused by calling show() without actually changing the color.
The connecting wire runs along the strip so it’s about 4 meters long. I am not using a level shifter. I might be wrong but the first few LEDs don’t have any flickering and afaik the WS2812B outputs the data pin with "a fresh new 5V from the 5V/GND power rails. So as long as the first LED works fine every following LED should work fine too (data wise at least).

I just connected my lab bench power supply to the other end which seemed to solve the issue so it does sound like a power issue. @Jeremy_Spencer

One thing I don’t understand though: When I dim the color (which would be the same as reducing the brightness) the effective brightness is even along the whole strip but it still keeps flickering (beginning at the last third of the strip) even though the overall current shouldn’t exceed any limitations regarding voltage drop should it?

I am not good at writing structured responses so please excuse me for rambling on but I hope you can gather some useful information from this.


That sounds like thin wire. You might try a larger wire, like at least 22AWG. Also, if possible, connect power and ground somewhere in the middle. If it’s multiple strips, it should be easy. If it’s one long strip, it requires soldering to the pads on the strip.

You might also try adding #define FASTLED_ALLOW_INTERRUPTS 0 before the #include <FastLED.h>, as described here:

It’s also worth trying physically pushing on the last good led and the first glitching led to see if either is loose

Thanks guys! I used a thicker cable and it finally works!