Trouble with (Defective?) LDP8806 LED Strip

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notgregor
 
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Trouble with (Defective?) LDP8806 LED Strip

Post by notgregor »

Forgive the long narrative, but I wanted to set the context for my request for support.

Last Christmas I used a LPD8806 LED light strand for some festive decorations. The wife and kid thought they were pretty cool. So much so, that they decided to get me another strand for a present. Life being what it is, I never really found the time to play with the new strand. Fast forward to the present and I'm getting out the light project to get ready for this Christmas. I'm having some trouble getting things to work with the old strand. (Turns out the problem was me having the microcontroller ground and the strip ground not connected.) In the process of troubleshooting my setup, I switch out the LED strip completely and notice that the "newer" strand doesn't seem to work at all. I should add that until I started this debugging process (within the last week), this strand was still unopened in its ESD bag.

The setup I have is a RaspberryPi controlling the lights using the SPIbus and a home-made wire that connects to the strand via the JST connector. I'm using the RPi-LPD8806 python library. The current state is and things I've tried are:
  • 1. One strand works fine, and when I disconnect it and connect the other strand, nothing happens.
    2. Both are full 5m strands.
    3. I verified that the input side of both strands corresponded to the JST connector I was using.
    4. The non-functioning appears to me to get warmer than the working and lit strip after an equivalent amount of time.
It seems to me likely that I have a defective strand; but I could be missing something obvious too. Any thoughts?

This is a picture of the setup with the working strand.
working_full_640x480.JPG
working_full_640x480.JPG (198.05 KiB) Viewed 271 times
And a close-up of the working strand.
working_closeup_640x480.JPG
working_closeup_640x480.JPG (179.13 KiB) Viewed 271 times
And for completeness, a close-up of the not working strand. You can see that the spool shows a different item #.
notworking_closeup_640x480.JPG
notworking_closeup_640x480.JPG (178.94 KiB) Viewed 271 times

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adafruit_support_rick
 
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Re: Trouble with (Defective?) LDP8806 LED Strip

Post by adafruit_support_rick »

Please email [email protected] with a link to this thread for a replacement strand

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hiduino
 
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Re: Trouble with (Defective?) LDP8806 LED Strip

Post by hiduino »

On your non-working strip, it looks like you may be on the output side not the input. Can you check the labels on the strip?

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notgregor
 
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Re: Trouble with (Defective?) LDP8806 LED Strip

Post by notgregor »

I figured out the difference.... The picture below shows both strands' input side and both are oriented with the 5V toward the top of the picture. The problem is that one strand has the connector oriented one way, and the other strand has the connector oriented the other.
connectors_reversed_640x480.jpg
connectors_reversed_640x480.jpg (188.85 KiB) Viewed 241 times
I figured this out after arranging for a replacement... Ideally I'd like to have 2 strands wired consistently, to chain them together and for my sanity. Would that be okay... Can I return which ever of my existing strands doesn't match the wiring configuration of the replacement? I'm not sure I can remove JST receptacle without breaking it (to switch the orientation). Or is there is some trick to non-destructively removing the wires from the JST housing?

As an aside, I am also kind of curious if there is a "standard" and one of the two is non-compliant? It looks like both strands are at least consistent with themselves, meaning the input and output sides match.

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adafruit_support_rick
 
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Re: Trouble with (Defective?) LDP8806 LED Strip

Post by adafruit_support_rick »

Probably simpler to cut and re-join the wires than to take the connector apart. Twist and solder the cut ends and cover with heat-shrink tubing:
https://www.adafruit.com/product/344

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