ESP8266 NodeMCU onboard LED flickering


I am using an ESP8266 NodeMCU with a SK6812 strip, WLED 0.12 and 0.13 tested. Everything seems to work fine, however, when the Light is on, depending on the effect, my radio picks up noise. I hear a humming with roughly 2 Hz. If I reduce the number of Lights from 200 to 30, the humming is gone. At first I suspected the power supply starts to oscillate, however, that is not the case.

The blue led on the NodeMCU flashes with roughly 2 Hz when the number of lights is set to about > 120. On the LED strip you cannot see a flashing, but maybe its just too quick for my eyes to see it.

Now the interesting thing: For debugging I disconnected the strip an still I observe the onboard LED flashing. After further debugging its obvious that the flashing frequency correlates to the fps I get from my effect.

So I guess whats happening is that my LEDs are switched off for a very short time at the fps rate. Too quick to see by eye, but the radio picks up noise.

I know the onboard LED is connected to GPIO2 on my device. So I already changed the GPIO Pin for the strip. Then the onboard LED stops flickering, however, the humming is still there, indicating that the strip still is switched on/off.

Any hints what I could try to fix this?

Hi and welcome to the forum , I tried with esp32 NodeMCU and the difficult part was finding a radio , i got a small one from my son but I could not pick up anything from esp32 , not sure if it is the radio i have or the esp32 vs esp8266 but I could not replicate the noise

IDK but my advice for you is to change channel or sell your radio . Just kidding , my advice is to wait for a better advice



thank your for trying to reproduce my problem!
I have now also tried an ESP32 → same issue.
But I think I’ve found the problem, the short data wire from the ESP to the LED strip in my installation (10cm) is the antenna. I need to properly shield this wire.


1 Like

For such a short distance you could try using a single twisted pair, use one line for data and the other grounded at the ESP32 and the strip.