Random white flashing wled esp32 dev3

1

hi all,

i’v got a lot of wled installs in my home. esp32’s and esp8266. so far working great.

thnx wled for the cool software!!

i got one setup dat recently random flashes white.

it worked good for about a year, just swaped out a new power brick and stil this issue.

checked wifi, no drop outs (got unifi enterprise setup, so can monitor it)

the install contains a esp32 dev 3 board, 2x WS2812B string. each 133 pixels.

length between esp32 and strings is less than 40 cm.

the strings got on both sides power injection.

Wled fw : 15.3

as i told earlier it worked flawless until recently…..

edit* : i saw the other topics and there are solutions mentioned as a level shifter… , but this setup worked flawles

2

perfect example for why we recommend to always use a levelshifter.

The mystery of the data level

Datasheet WS2812B

https://cdn-shop.adafruit.com/datasheets/WS2812B.pdf

Needed data level of LED

Looking at the datasheet page 3 we see that the minimal voltage for a high level input is 0.7*Vdd.
Vdd is the supply voltage of the LED, so 5V in this case. 0.7 * 5V = 3.5V

Data level output of ESP

The ESP can only output 3.3V.

Conclusion

The output of the ESP is in theory not high enough to drive the WS2812B LEDs.
A levelshifter does fix that issue by changing the datalevel from 3.3V to 5V.

But it works without one in Video XY

As said above: " …in theory…". Values from the Datasheet and the reality are two different things.
The values in the datasheet mean that it can garantee a good read of a HIGH level at 3.5V or more. It can work below 3.5V, but there is a chance does not get a good read.

And now?

If you want a reliable setup, then integrate a recommended levelshifter. Check the /shifter command for those.

1 Like
3

Hi thnx for your answer,

But i don’t reverence to the XY video.

And i mentioned al the other installs work fine.

And this one until not long ago.

So whats’s the catch? Latest update made the data signal less “strong” doubt that.

As i mentioned the line is shorter than 40 cm.

4

that is a standard text, contents applies exactly to your case: run it out of specification, expect random things.

5

This is also a good video from VCS from years ago. They only really talk about 5v data (levelshifted), but it is still a good breakdown of what happens to data signals. https://www.youtube.com/live/9ttEAyiyTAI