LED color glitches/flashes

[coelner]

Hey,
I use 120 WS2812 wit a 4A 5V power supply (limit 3800mAh). The firmware is 0.8.5 on two different ESP8266 boards. I want to use a self soldered ESP12E board with minimal space requirements. With this board I have some LED glitches. Most of the time the selected color is shown, but randomly short burst with a different color appears. A single level shifter is also used, but the led stripe works flawless with a nodemcu even without a level shifter.
If I set the brightness the glitches don't appear, all other glitches are with full brigthness. If I use only a red color, those glitches are mostly green, sometimes blue. Most of the time the complete stripe is affected, but sometimes only the first LEDs burst the wrong color.

Any hints where to search for solving the issue?

[theshadowsvk]

Hello,
please, which pin/method are you using ? Are you sure that voltage drop is not big ? Sometimes this could be the issue of random color glitches.

[coelner]

I use GPIO2. I flashed it with a CH340G directly over the gpio pins and took this one: WLED_0.8.5_ESP8266.bin
Which voltage drop do you mean? with full brightness it is 4.9V and at end 4.2V (With power limit set to 3800mA). But this should not be a problem, the nodemcu can be used for this and there are no glitches at all (at the end 3.8V)

[theshadowsvk]

Hmm okay, can you drop schematics of your board ? This sounds like other problem

[coelner]

[theshadowsvk]

One question, is the common ground shared between 5v and 3.3v line ?

Sorry I see now, it's shared. I saw that cross line wrong. I'll check my schematics of my board and let you know

[coelner]

Yes, it is.

[Aircoookie]

Your setup looks good to me. I actually believe that this is indeed a software issue because I have had it too on two of my lights. I was suspecting that the reason was a missing levelshifter, but might be an occasional flipped or dropped bit in the UART after all.

[coelner]

I'm not sure. The nodemcu works well even without a levelshifter. At least I get there no glitches. And the single ESP12 feels hotter than the nodemcu (measured with my finger tip...) but this could be the missing pcb underneath.
I assume two issues, one with flipped values in the UART, but somewhere a hardware vault.
https://streamable.com/o8lsz

[Aircoookie]

Thanks for the video! For me it looks exactly the same, albeit at a much lower frequency at one glitch per 20-60 minutes, not every few seconds. This indeed seems like more of a hardware issue, but since there is no hardware difference with the pin between ESP12 and NodeMCU I can't see where. Did you try without the levelshifter? I've recently heard that some models modify the waveform enough to cause issues.

[coelner]

Yes, I added the level shifter after these glitches appear.
Those esp12 are mass products, maybe something is broken inside (which would explain the hotter surface). sadly I have no oszilloscope otherwise I would inspect this furthermore.

You can close the issue and leave a reminder if LEDs are flickering that it is maybe a direct hardware issue.

[coelner]

Ok, even the nodemcu has got the glitches, but more like one in a hour.

[frustreermeneer]

I'm experiencing the same random flashing problem with 249 LEDs on an older Lolin NodeMCU on pin D4/GPIO2.
I didn't have this problem with FastLED on another GPIO pin.

[kcoop99]

Experiencing the same issue. Random color flashes. Running 12v lights. Has this been determined to be hardware only?

Here is video of my glitch examples. Solid blue then with Halloween effect.
https://youtu.be/TGyMkZldP5s

[kcoop99]

Swapped my wemos d1 mini for a node mcu and am running into same issue. Leads me to think it's software and not hardware.

[wardwygaerts]

My leds seems to flicker all together when changing color. Will make a video tomorrow.

[dhami220]

I get the flashes as well (every few seconds) with couple interesting observations below.

My setup: Two LED strips controlled by two nodeMCUs, two level shifters and 40amp power supply.

1. If only one LED strip is running, I don't get any flashes.
2. If I turn the second LED strip on, the flashes appear.
3. If both LED strips are set to halloween, no flashes. I have tried other effects, but only found halloween working without flashes when both are ON.

[dhami220]

Tried a few additional items without success:

• I have wire nut on the data cables. Replaced that with soldered joint. Same result.
• Removed level shifter (connected directly to nodemcu). Same result.

Next steps:

• I have two small strips. Going to give those a try right next to mcu to rule out data cable length and/or excessice number of LEDs on my main strips (~320 per strip is what i have. the small ones have ~20 LEDs).
  RESULTS: No flashes. Could be the length of the data cables or number of LEDs or some abnormality with connections on the main strips.

• Used LED as the signal booster with the main strips.
  RESULT: Flashes.

• Replicate flashes with longer data cable and small strips (Isolate longer data cable variable from the number of LED or connection abnormality).
  RESULT: -

• I have seen some posts about capacitor. Will give that a try if I can find a similar capacitor.
  RESULT:

• Place Nodemcus closer to the strips.
  RESULT: inconsistent node MCU power behavior. When the strips are on, the nodemcus turned off. I measured the voltage and it was close to 3.04V. It appears that this may be related to voltage drop from the power supply. I had nodemcus connected to the same power supply, and may be nodemcus (even when closer to the power supply) are not getting sufficient power and that causes data signal issues. Two items to try: Ordered 60amp power supply from amazon; try powering nodemcus from a separate power supply.

Final Outcome:
After watching Dr's stream today, gave the booster LED another shot. This time, I ran both strips from one NodeMCU (same signal split to both). Soldered all joints (replaced jumper cables with 20 gage wire segments and soldered). Flashes are gone!!!

[kcoop99]

Can anyone confirm or deny that a logic level shifter DOES work???

[theshadowsvk]

Yes I'm using it, without any problem

[kcoop99]

Would you be able to share which one you are using and how you have it wired?

[Physikus74]

Hello,
that sounds to me like EMV problems, or actually voltage dips due to pulsating currents in the effects. A good buffering with capacitors near the MCU should help. It is even better if the MCU gets its own power supply. So the "big power supply" for the LEDs can be switched from the MCU and the MCU itself is independent from the currents of the LED's. When designing the GND line you have to be careful that the current through the LED's does not influence the voltage of the MCU! For me such a setup with more than 900 LED's works very well.

[palengh]

Thank you for your great effort with this project. I really appreciate it.
I too experience the random flashing of the lights.
Running WLED 0.8.5, and using a 5 m 300 LED strip. My power supply is 12V (12.5 A) directly to the LEDs sharing the common ground with the NodeMCU. My NodeMCU has D4 connected to the
LED´s program wire. When setting Max current to 12500 mA, the LEDs flashes like strobe light. I need to set the LED Max current to below 2000 mA, to stabilize it, but even then it will flash randomly. When I disconnect the D4 connection, it's stable, even at 12500 mA.

The D4 connecting cable is 8 cm long.
Setting "skip the first led" in the configuration dit not help

EDIT: Upgraded to WLED 0.8.6, and the strobe-like flashing is gone, even at 12.5A. Now it only dips to lower intensity randomly. This behavior seems to be gone when max power is set to 5A, but then the brightness/intensity is too low.

[austwhite]

I am using WS2811 LED's and I get the flickering issue quite badly when using default GPIO2 (D4 on D1 Mini) or GPIO3(Rx on D1 Mini) for the LED data. Strangely, the flicker only happened if I set the current to above 1000mA. If I limit the brightness, no flicker at all.
I decided to play with this. I changed to use GPIO14 (D5 on the D1 Mini). The compiler warned me it would use software bitbanging which may cause flicker, but the exact opposite has happened. The flicker I was previously getting is now totally gone. Even at full brightness no flickering.
It isn't a hardware issue either as I have used 3 different D1 Mini's to test with (one was a D1 Mini Pro, genuine WEMOS, two are clones).
I haven't got a WS2812 to play with at the moment, so I can't comment on that, but on the 12V version WS2811 I have this seems to have solved the flickering completely.

[kettenbach-it]

Just connect the GND from the LED strip to the GND-PIN of the Wemos Board.
If it still flickers it might be something else.

[jnpatrick99]

I experience strong flicker and white flashes. I found it seems to depend on the LED Configuration, for example when brightness is low, and "Make a segment for each output" is on it flickers much more (every second). When it's off it flickers once in 15-20 seconds. Also different effects produce different flicker times. On Solid color there's only a few flickers.

So to me it looks like it's software rather than hardware. After I change parameters sometimes the flickers disappear completely.

It started only with recent updates and multiple LED strips support. When I had one strip and older firmware there were no flicker at all. Now I have three (~250 LEDs each).

[Model-Man]

Are you using any type of level shifter on each individual output? If not you should to stop the flickering.

[BarrettLowe]

I found that this happens when I've got two segments using the same set of LEDs. I had segment A running leds 0-170, segment B running leds 0-100, and segment C running leds 100-170. Segment A was on (solid), while B and C were running effects and I was getting a flash, what seemed like, precisely once a second. Maybe this helps someone but perhaps software should handle this situation.

[SteveoMS]

I am running two BFT WS2815b 144 pixels 12v and I get a flicker of white every fews seconds. I have the WLED 0.13.0-b6 toki running. ground is shared mentioned above. I am power injecting both strips now but same issue. One strip seems to work fine.

No level shifter

[Riggaa]

I think that this issue is largely derived from the LEDs simply running too hot and failing over time. I had the flashing issue after awhile for all of my 60LED/m SK6812 RGBWW strips. I switched to 30LED/m and haven’t had a failure yet. I believe that the higher populated LED strips get hotter and due to having double the SMD components/m there is a higher chance of failure.

In my experience once a strip starts to flicker they’re pretty much done with unless you drive them at a lower current.

[jnpatrick99]

In my case it's definitely not the strip being hot. I'm not sure why I need level shifter but I was able to suppress the issue by randomly changing modes many times on the strips. Now I have 3 strips, 250 LEDs each, connected to the same ESP32 on almost full brightness, they never flickered since then. Now I'm scared to change any WLED parameters though.

[Bascht74]

I have some flicker as well with my quinled quad and WLED 0.13b6. I switched to WLED 0.12 and it ist much, much better...
Does somebody else see this behavior with the different versions? When I switch to a cheap LED-Controller (only the data cable), everything is Ok...

[alax]

After switching to a QuinLED Uno, I don't have any more flicker/glitching at all with my UCS2904 LEDs. For reference, I have 275 in one string, spread out over about 150ish linear feet.

Before, I was using an ESP32 with a 74AHCT125 level shifter, all grounds tied together, and I messed with just about every setting on WLED. Animations would have random pops of color, and my white channel would also randomly activate.

Since it was hand wired/hand soldered, I think the issue here really is related to the quality of the connections between components on the PCB, and the connection to the strip itself. A direct swap for the QuinLED PCB fixed everything straight away.

[stale]

Hey! This issue has been open for quite some time without any new comments now. It will be closed automatically in a week if no further activity occurs.
Thank you for using WLED!

[jmerc77]

getting the flickers flicking me off too. most noticeable with aurora effect. using 0.14.0-b1 compiled for my ESP32-S3. did further experimentation and found the current limiter in led settings to be the problem. if set less than ~30% of the max amperage it starts flickering. I have 288 ws2812b leds connected. its 2 1m strips directly soldered end to end. sig on gpio16 (default). brightness setting of 255.

I did not have the patience to buy a level shifter but found a clever "hack" that gets by with a diode and resistor. apparently, 5v at low-ish current on esp32 outputs does not cook it. so gpio-facing diode with resistor to 5v, tapping between to led sig line worked well. just be sure that its a Schottky diode or something else with fast switching speed due to high frequency sig.

[Riggaa]

Though troubleshooting I have determined that the 60 LED/m will run too hot and damage the led at a certain point. I switched to 30 LED/m strips and and I have yet to have a problem since. I’m not certain that that was the issue, but it’s the most logical conclusion I can come to.

[jmerc77]

mine are 144 leds/m. barely used. also tried setting brightness lower instead of lower current limit. no flickering! only flickers when limiting current in settings <30% and only on dim lights during animation. not sure if it will happen on solid color yet though.

[Hubert97]

Afrer upgrading from internal linear power supply to external dc/dc converter i started to notice those flashes. Usually in plasma and aurora mode. I am running 680 w2812. I think that this may be caused by bad gnd connection. I' ll make a bypass to led strip and update if that worked or not.

[sniicker]

I had extreme glitches. NodeMCU seperatly powered per usb and sk6812 from btf with extra power supply. ~200leds

I could simply fix it by replaceing the usb cable the NodeMCU was powered. No flicker no glitches.
Works perfect.
Give it a try. Mybe you usb cable is shit.

[jmerc77]

I'm not using a usb cable for power. my strips are 5v and I am powering BOTH off the same source. this may be the problem though. as far as the circuit of the esp32s3 im using goes, there's a diode between both 5v inputs and the 3.3v regulator. so if the esp is browning out, i may be able to simply add a few hundred microfarads between 3.3v and ground. also my power supply was only 2A and fried during a 24 hour test. getting a 15A supply which will come within 7 days since I have 2m with 288 leds total. also have fuses on the way.

[github-actions]

Hey! This issue has been open for quite some time without any new comments now. It will be closed automatically in a week if no further activity occurs.
Thank you for using WLED! ✨

[BarrettLowe]

For me, at least, this was happening because I had multiple segments overlapping. Once I made sure each LED was in one, and only one, segment. The issue went away.

[lyrixx]

Hello, I have a similar issue, but xith a RGB / PWM led strip

I used :

• a good ESP32 (works very well with WS281x strip)
• an RGB amplifier (aliexpress)
• a non adressable strip (not this one, but similar)
• amplifier is connected to 12V
• ESP is connected to 5V via VIN
• No USB is involved

I followed this schema :

found on this page

When I measure the voltage before the amplifier, I see from 0 to 1.6V between V+ and R or G or B (depending on the "solid" color I chosed)

But I also see 0.08V at the output (whatever the R/G/B or my setup)

I tried 3 different RGB amplifier (but same model each time), and it's the same result.

---

Note

• When powering ESP via USB, I got flashed
• When powering ESP via dedicated AC, I got nothing anymore

[mkovero]

Does it help if you connect GND from power source unit to the esp32 GND?

[sniicker]

Connect the input Power of the Amplifier

[lyrixx]

Sorry for the lag

@mkovero

Does it help if you connect GND from power source unit to the esp32 GND?

No, it's almost the same. But instead of getting 0V, I got 12V (but it's always this value, whatever the color is choose)

@sniicker

Connect the input Power of the Amplifier

I don't understand, Th input power of the Amplifier is already connected 🤔

It's the same issue with the other power input