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30 LED strip - no longer working
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30 LED strip - no longer working

by jjeanjaquet on Thu Aug 10, 2017 3:06 am

I've had my 30 LED strip for two days. I finally got everything working using a raspberry pi and the sample here: https://learn.adafruit.com/neopixels-on ... i/software. Everything was lighting up like a dream, and all samples looked great. I picked up the whole assembly to move across the desk and suddenly the strip has devolved into a flashing epilepsy inducing series of random/incorrect colors.

I'm wondering if maybe the end wires (that are unmodified and exactly as delivered) crossed and caused a catastrophic failure in the strip. All pixels do light up, although the first 10 are the most sporadic. My light strip is dead, isn't it?

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Re: 30 LED strip - no longer working

by adafruit_support_rick on Thu Aug 10, 2017 9:52 am

Please post some clear, detail pictures of your wiring and soldering

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Re: 30 LED strip - no longer working

by jjeanjaquet on Thu Aug 10, 2017 10:11 pm

I have the LED Light strip connected via breadboard, and it is in the same configuration as when it was working. I've isolated as many variables as I can and determined that everything except the light strip is working as intended. I've included images but I doubt they will be much help.

IMG_20170810_004510493.jpg
IMG_20170810_004510493.jpg (201.94 KiB) Viewed 126 times

IMG_20170810_194757723.jpg
IMG_20170810_194757723.jpg (160.58 KiB) Viewed 126 times

IMG_20170810_194847945 (1).jpg
IMG_20170810_194847945 (1).jpg (174.6 KiB) Viewed 126 times

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Re: 30 LED strip - no longer working

by adafruit_support_rick on Fri Aug 11, 2017 9:35 am

Maybe I'm missing it in the pictures, but you don't seem to have a common ground reference between the pixels and the Pi.

Is that a diode on the power to the strip? Is that to lower the strip voltage?

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Re: 30 LED strip - no longer working

by jjeanjaquet on Mon Aug 14, 2017 12:20 pm

Ah, yes. Apologies. I did have a common ground but I was messing with different types of ground to see if that had any effect, which it did not. I snapped the pictures without returning the ground to the original location.

The diode method is a quick way to reduce the power supply voltage slightly so the NeoPixels can read the Pi's 3.3V output. It was working fine in this configuration until such time as it all stopped working fine.

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Re: 30 LED strip - no longer working

by jjeanjaquet on Tue Aug 15, 2017 10:32 pm

I've attempted to:

* Use the native 5V on the PI
* Bypass the diode to use the full 5V from the power supply
* Create a common ground

None change the behavior. As mentioned before, this did work for an hour or so but doesn't anymore. Should I get in touch with support?

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Re: 30 LED strip - no longer working

by adafruit_support_rick on Wed Aug 16, 2017 4:27 pm

jjeanjaquet wrote:I've attempted to:

* Use the native 5V on the PI
* Bypass the diode to use the full 5V from the power supply

That definitely won't work. 3.3v logic signals are too low when the pixels are powered at 5V. 30 pixels on the Pi's 5v output is also not a good idea.

Actually, if the pixels are lighting up, even if it doesn't look right, then I don't think there's anything wrong with them. When they fail, they stop lighting up at all. So there's something else going on. Not sure what that would be, but you've got kind of a baroque wiring scheme there - I'd suspect that it's a problem with your jumper wires or breadboard.

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