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Random color flashing in WS2815 strips
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Random color flashing in WS2815 strips

by Aspid on Sun Oct 24, 2021 4:26 pm

Hi!

I build Phillip Burgess's Holiday Icicle Lights with Flair but used a WS2815 which should work the same way as WS2812B, but is powered with 12V instead of 5V.

So cut the 5m strip into 7 pieces and soldered everything. I hooked it up to the M4 Feather Express and a NeoPXL8 Feather Wing with quick connects.

Video: https://www.youtube.com/watch?v=4nlZK2CM5vo

All strips are working to find and show the drop animation. But two strips flicker in all possible colors and I can't find out why. I checked everything, connected additional ground wires...



Are they just broken?

Aspid
 
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Re: Random color flashing in WS2815 strips

by mikeysklar on Tue Oct 26, 2021 5:48 pm

Does the problem follow the strips? eg. If you swap the two strips that are flickering with the two that are not changing (moving the quick connects for each strip) what happens? Does the problem follow the flickering strips to their new location or does it stay and effect the freshly moved non-flickering strips?

mikeysklar
 
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Re: Random color flashing in WS2815 strips

by Aspid on Wed Oct 27, 2021 7:26 am

Yes, it does follow the strips...

Aspid
 
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Re: Random color flashing in WS2815 strips

by mikeysklar on Wed Oct 27, 2021 4:14 pm

Since the problem follows the strips it is likely the strip itself or more likely the connections between the flickering strips and the NeoPXL8. Can you show a photo of a "good strips" connection to the NeoPXL8 and a flickering one. I'm curious if something is different.

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Re: Random color flashing in WS2815 strips

by Aspid on Fri Oct 29, 2021 6:29 am

I tried to take pictures, but it did not work well, because the connections are under transparent shrink tube...

To stop the random flashes, I tried all of this:

    I disconnected the wires from the strip, cleaned the connections and soldered again.
    I connected the backup data of the first LED to ground.
    I connected the backup data of the first LED to data.
    I connected a 300 ohm resistor in series at the start of the data line near the controller.
    Since the first two LEDs in one strip did not flash random colors, I cut the strip after the after the third LED and connected the remaining strip.
    Since I was told, this could be a grounding error along the strip, I soldered an additional ground wire to the ground pin at the end of the strip.

Nothing changed at all ...

Aspid
 
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Re: Random color flashing in WS2815 strips

by mikeysklar on Fri Oct 29, 2021 11:41 am

Okay, thank you for trying those additional steps to understand what is happening.

Since the problem follows the strip sections it seems likely those two sections of strips are compromised.

Had you purchased the WS2815 from us? If so, when?

mikeysklar
 
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Re: Random color flashing in WS2815 strips

by Aspid on Tue Nov 16, 2021 4:06 am

Hi!
It took some time to figure it out.
Your first question: No, the strips are from BTF-Lighting. As far as I know, Adafruit does not sell WS2815 strips.

What I did:
I changed the power source: still random colors.
I changed all wires and soldered everything another time: No change.
I added a big electrolyte capacitor: No Change.
I used an Lolin D32 ESP32 controller to control the strip: Everything words fine, no random flashes anymore!

So I started digging. It took quite some time until I found this page: https://adafruit.github.io/Adafruit_Neo ... index.html

0/1 bit timing does not precisely match NeoPixel/WS2812/SK6812 datasheet specs, but it seems to work well enough. Use at your own peril."


Might this explain the issue? If yes, can I fix it somehow? Or build a work around?

Aspid
 
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Re: Random color flashing in WS2815 strips

by mikeysklar on Tue Nov 16, 2021 3:42 pm

I think the "use at your own peril" is a pretty solid disclaimer.

Good find digging around for it. Are you going to stick with the Lolin controller since that worked?

You can open an issue on the github repo so the problem is documented and has the possibility of getting resolved.

https://github.com/adafruit/Adafruit_NeoPXL8/issues

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