Goofy WS8201 25 flat LED (#738) problem

by soze on Sat Feb 23, 2013 7:08 pm

Hiya Adafruitarians!

I bought two strips of the 12mm Diffused Flat Digital RGB LED Pixels (product #738). One strip is rocking it like a champ with the test code and making me a happy soze. However, the other one only turns on one LED, at the far end of the strand, whose connection seems at times spurious. When I wangle the cord lightly (pick up the pixel, move it up or down for visual inspection, nothing extreme), the color wanders all over the place, occasionally going dark, occasionally going full white, and any color in between.

When I test each strand individually with the test code, the well-behaved strand behaves as expected, and the poorly behaved strand does not light up at all.

FWIW, the working strand has the arrows (pointing in the right direction from the connection). The misbehaving strand has no such arrows molded into the sides. Both came in #738 bags.

So, basically, what's my play here? Do I have a bad strand or do I just need to take my stuff back to the drawing board? Please and thank you. :D
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Re: Goofy WS8201 25 flat LED (#738) problem

by pburgess on Sat Feb 23, 2013 9:10 pm

Gack...I suspect the supplier changed the pixels recently (it happens from time to time) and you have strands from two different batches.

If you have gator clips or wires or whatever it looks like it would take, try connecting just the "bad" strand to the Arduino wrong way 'round (ie connect to what looks like the output). You might need to swap data & clock, but 5V and ground should be obviously colored.

If that works...either we'll swap out to get you matching a matching pair, or if you're comfortable with a little clipping & soldering you can rejoin the two that way.
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Re: Goofy WS8201 25 flat LED (#738) problem

by soze on Sun Feb 24, 2013 2:10 pm

Managed to find a stopping point in my project to be able to do this. Looks like your supplier indeed flipped the ends.

So, if you don't have the arrow molded into the side of your pixels, your input is going to be the MALE end. Otherwise, for strips with arrow molding, input is the FEMALE end.

Color order of wires does not appear to have changed between the two versions; plug red to red, blue to blue, yellow to yellow, green to green, to make two different strips work. I do not appear to have any weird signal loss even over jumper wires.

I may end up slicing up this string anyway, so no worries about a replacement. Thanks for the super-quick weekend response, and glad we could figure it out! :)
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