Flickering random colors

Hello all! My led are flashing random colors.
My setup

  • total 24 strip esp8266 (powered with mirco usb and ground connected to led and PSU)
  • WS2811
  • 12v 3A PSU (amp limited to 1.2 A in wled app)

I’ve read about levels
Reason 1,2, and 4 is not related to this problem. And I’m wondering if reason 3 (levelshifter) is the cause of this flickering. But, I’ not sure if it is really the problem, since there are times when my led works perfectly fine.

When I connected the esp to a single long strip it works perfectly fine. And when I connected to this led setup ( leds connected with parallel and series) It shows random colors. But, when I lower the brightness to 40, it works fine again. I’m really confused and have no idea what is causing this problem, because it appears randomly (sometimes it works and sometimes it’s flickering). It is because I’m not using levelshifter or the parallel connection?

yes, missing levelshifter can cause this. primary reason actually.

Thanks for the reply. Is there a reason why the flickering didn’t occured when I connected it to a single long strip, but when I connected it to the other setup the flickering happens?

the reason is luck. without a shifter, you are not within specifications of the LEDs and if they work or not has to do with tolerances.

Ok thank you very much

@dedehai I couldn’t find the recommended level shifter from Other Hardware - WLED Project neither 74HCT2G17 from your page in my country. I could only find SN74HC125N and SN74HCT32N. I noticed that you’ve tested 74hctxx. Will it work? If so should I use the same capasitor and resistor shown here Other Hardware - WLED Project? Thank you

it needs to be a 74HCTxxx (the T is important). SN74HCT32N works, just wiring is different as this is an OR gate.

The first diagram on the KB Levelshifters page (“Other Hardware …”) has the diagram for the 74HCT32 (same as 74AHCT32).

When running strips in parallel you are splitting the data signal, reducing it’s power to each leg and without a level shifter you are already below the correct data signal spec. Even with the shifter if you split the data too many times you will still have flickering, requiring a booster. I did not run into the problem till I got over something like 15-20 splits while using a level shifter**

And one other easy trick - send your data line to more than 1 level shifter.
Each shifter then becomes a brand new valid data source.

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Thank you Jinx, that explains why it didn’t flicker when I connected it to a single strip. I’m planning on to only use 6 splits so I think that won’t be a problem if I use a single levelshifter. But I couldn’t find SN74HCT32N either in my country. There are only SN74HCT245N and CD74HCT32E both are missing the letter (A)HCT and the second one has the letter CD instead of SN. Will it work? and will it use different capasitor, resistor and wiring from the diagram used on Other Hardware - WLED Project? And TXS0108 is very easy to get in my country but I’m aware that it’s too slow for WLED. Which one should I get?

The SN74HCT245N should work fine. It is the same as a 125 but offers 8 I/O’s vs 4 so it will be a bit larger. You still need the .1uF cap. I would not use any resistor unless you find that you need one.

Wiring diagram from KB:

AHCT is a more advanced (faster) chip and is more power efficient than the standard HCT, but the HCT should still work.

Thank you so much

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Sorry last question. I’m using an external 12v PSU for the WS2811 and stepdown to 5v for the ESP82266 and the SN74HCT245N. I just want to make sure, is this the correct wiring?

looks good to me.


The only other thing to watch out for: make sure you ground all the unused inputs of the '245 (as shown in the wiring diagram).
Floating inputs will cause flickering as well.

Yep, I’ve connected all the unused input to ground. There was not much flickering in solid mode (only flicker when changing colors), but in other modes it was still flickering (first three leds working fine). And now lowering the brightbess doesn’t stop the flickering. I have no idea why is it still flickering.

Note: I haven’t got the 5v stepdown so I’m using microusb connected to my laptop, and I conected the vin from esp to the levelshifter.

If that yellow wire is a dupont bread board jumper wire I would use something else. Those at times can make poor connections and are very small gauge.

I got to ask… Why the odd strip setup with them running in parallel? and that one set of 2 strips are coming off the other one before it’s last set of pixels?

My next step would be to improve the ESP supply side of things. A proper dedicated 5V supply (or 12V-> 5V buck converter