WS2812B Wrong colors

Sorry for the long silence, I was away from home.

I found what the issue is: it’s one of the 2 kinds of LED that I purchased that creates it…
individual LEDs

I have replaced them by the other model (LED strip), and voila…

I though it was not the hardware because:

  • Some from the strip also had wrong colors. I suppose the signal was polluted though the individual LEDs?
  • When I swapped the 2 first individual LEDs, the wrong colors remained the same, according to their position, not to the LEDs itself.

Thank you very much for your help Mike!

Thank you very much for your help Mike!

Your very welcome, and thanks for the feedback to conclude this thread. Often people just leave things hanging, or just say it is solved without saying why.

I know this is an old post - But I wanted to seal it up so people knew what the problem was. I am 99% sure you were using RGBW (note, the forth LED, WHITE). That will then create a chain of issues since you need to send FOUR individual codes per LED. It chains over to the next one in line, and goes forever.

Just adding to this rather than creating a new thread. But one of my strip is showing randomly wrong colour leds, however only when below 50 percent brightness. If I fade it down then some led stay in brightly with the wrong colours. If I put full brightness and then reduce then the colours are all as expected until the brightness get low again.

This is only on one strip, my other strip with the same code is perfectly fine.

I have a 1000uF cap on the +/- supply of the strip. I have a 220 ohm resistor on the data pin of the strip. All cable lengths are reasonably short.

I believe the supply is just over 5V at the start (5.15V off memory) and very close on 5V at the end.

Should I look at my power supply, changing my resistor or looking at using a new gitial pin.

Its a buy of a pain to change things in situ which is why I haven't tried these things yet.

This is only on one strip, my other strip with the same code is perfectly fine.

Look to see if this strip has a ceramic capacitor on every LED. I once got a strip that only had them fitted on every eighth LED.

I cut a 5m strip in half at the cut marks and made thr two strip’s. So each strip is the same, other than the one working 100 percent running off a lab power supply with no capacitor or resistors yet, and the one not working right when dimmed down running off a plug pack however has the capacitor and resistor in it… I had hoped addimg the capacitor and resistor would fix it but it made no difference to random wrong pixel colour (or individual pixels night when the rest are off).

I will check about the capacitors on the strip however.

As the led work fine at 50 percent and upwards in brightness I was thinking that the strip isn’t damaged and it’s not to do with voltage drop. But this is an uneducated stab at the problem.

and the one not working right when dimmed down running off a plug pack

I am assuming that a plug pack is some sort of power supply. I am also assuming that the ground of this plug pack is also connected to the ground of the Arduino and the +ve is only connected to this second strip. Is this correct?

running off a lab power supply with no capacitor or resistors yet,

Well put them in as soon as.

Grumpy_Mike: I am assuming that a plug pack is some sort of power supply.

|500x500

Grumpy_Mike: I am also assuming that the ground of this plug pack is also connected to the ground of the Arduino and the +ve is only connected to this second strip.

Yes common ground for the strip and the wemos. The positive of the supply is only powering the wemos mini and the strip it's controlling.

Grumpy_Mike: Well put them in as soon as.

Yes that is the plan before I keep using them. However thats the strip with no problems. But I realise that over time it could damage them.

Grumpy_Mike: I am assuming that a plug pack is some sort of power supply.

Yes like linked above. I haven't checked is it's regulated or switch mode... I know it's not an unregulated supply though.

I haven't checked is it's regulated or switch mode... I know it's not an unregulated supply though.

It will be a switch mode supply given the size and weight.

Any thoughts why it's only a problem at lower brightness or off? Could it be a data line issue?? Or perhaps the strip is damaged? Although seeing it works perfectly fine at the higher brightness makes me think power and the leds plus drivers are ok? This is a question not a statement as obviously I'm not too sure.

Maybe I try a different value resistor or maybe try a different digital out or perhaps borrow the esp8266 from the strip working properly? Problem is I may need to pull the strip's down and unsolder plus resolder so I'm a little hesitant unless there is reason for the problems to only be at the lower brightness or off for me to do that.