SK6812 doesn't seem to be working with WLED

Issues
1

Alright, I had an existing NodeMCU/ws2812b setup to light the underside of a shelf. Due to the low number of LEDs, I could power this completely off a USB 3.0 connection (conveniently on the back of the router situated on top of that shelf). But, they were 30/m and not dense enough to be really bright. Plus, I wasn’t overly fond of the purple-white that’s considered “white” on those particular strips.

So, I bought some SK6812 RGB+NW strips. One was a 144/m strip, the other a 60/m strip (the intention for this one was for future use it in the kitchen). I wired up the 144/m strip to my NodeMCU on D4 for data and a separate 5V/15A power supply (as I’d now gone from 24 LEDs to 113, but it was still an intentional overkill on amperage) and…

All LEDs were bright white with a slight colour variation flicker! But only if the NodeMCU was powered on with the strip. Otherwise, I got nothing (LEDs would stay on a power up and disconnection of the NMCU however). If the NodeMCU were powered up after the strip, I could watch the power slowly “walk” up the line until all LEDs were flickery white.

Any kind of change of state (effects, colour change, etc.) just led to additional flickering of the LEDs.

Alright, I checked all my connections, but nothing seemed awry.

So, I tried a different power supply on the sk6812s; a 5V/10A supply I use for the WLED-based Ambilight setup on my TV’s ws2812b’s. Same results.

I used a different power source for the NodeMCU. No change.

I flashed a second NodeMCU. Exact same problem on a fresh WLED install.

I tried every combination of 3-channel, 4-channel and byte order. All the same.

My thoughts then were it’s an issue with WLED. So I flashed an NMCU with Tasmota. Same problem. All white, no control, slight flicker (though somewhat lesser with Tasmota).

So, power supply isn’t the problem, WLED isn’t the problem, NodeMCU isn’t the problem.

I hooked up the second 60/m strip. Exact same problem.

These strips were bought from BTF. So I don’t feel there’s any issue with their provenance and that they’re legit and of a fairly decent quality.

Am I missing something here? Are there new sk6812 chips that are incompatible with the previous data instructions? Because this really seems like a data issue (given the additional flashing during effects/state changes/etc.).

Can anyone help?

2

The standard answer seems to be, are your power supply and NodeMCU 0V lines tied together (bonded)? Do you have a 1000µF capacitor across the 5V / 0V lines as they go to the strip? How long is the control line from the NodeMCU to the strip? If it does not have a level shifter, or large wiring, the voltage drop before reaching the led strip might steal the WLED control signal from reaching the LED strip properly.

My experience is the bonding of the NodeMCU and strip 0V is to blame.

2 Likes
3

Well, that was quick.

It would appear bonding the tying the grounds together did make the difference. Why is that?

4

Check google for “floating ground” problems and see if that helps you understand.

5

Just wanted to say that I’ve been pulling my hair out for a week trying to get WLED and other ESPhome products to work with my ESP32 and the SK6812. After hours of googling, I finally came across this thread. I bonded my grounds together and it worked! Thanks!