Light Problem with Arduino Uno and Neopixel

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TastyOs
 
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Light Problem with Arduino Uno and Neopixel

Post by TastyOs »

Hello there.

I recently purchased the Arduino Uno (https://www.adafruit.com/products/50) and the 30 LED digital NeoPixel strand(https://www.adafruit.com/products/1460 ). When the goods arrived, the Arduino worked well, as I tested it with the 'blink with out delay' example program. However, I found that the wires were soldered onto the wrong end of the light, denoted by the flow arrows. I didn't plug in because I knew they were on the wrong end.

I cut them off. I connected them to the power and ground pins on the Arduino and applied the ground to the ground terminal and I tapped the power on the 5v terminal. *Most* of the whole strand flashed. I read it would do this if the Dout wasn't connected. The wires were carefully re-soldered onto the correct side. I was dismayed to find that only three of the lights were working with the strandtest example when the Dout was applied.

I let it sit for a while, and I came back with an idea. I knew that power was getting through the strand. I saw them all flash earlier. I believed the fourth light to be faulty. I carefully made an incision on the terminals after the fourth light. I knew that power would get through so I applied the Dout to the terminal I opened access to. Miraculously, 30 lights came on, following the strandtest example.

I repeated these steps after the lights stopped, and found three more really short strands isolated between bad lights. I came to the conclusion that power flows through the strand, but Dout does not.I am at a loss for what to do. Any help fixing the bad pixels would be appreciated. I will look into product replacement if the strand cannot be fixed.

Album Pictures: http://imgur.com/a/JRBNi#0

On the Arduino, the red wire is plugged into 5v. As I took Dout off and reapplied it to other parts of the strand, the parts already lit retained their color, giving you what you see. Nothing after that last blue light works. I think that one eats power or something like that. Like I said, ask questions if you have them and any help is appreciated.

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adafruit_support_mike
 
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Re: Light Problem with Arduino Uno and Neopixel

Post by adafruit_support_mike »

Each NeoPixel acts as a data buffer for the rest of the strip.

A pixel consumes the first 24 bits of data it sees on its DI pin, then copies everything else to its DO pin. The next pixel consumes the first 24 bits it sees, and passes the rest on, etc.

That eliminates a lot of problems involved in sending data signals over long wires, but it also means that losing a single pixel will stop data from getting to the rest of the strip beyond it.

Your testing showed exactly the results we'd expect from a strip with some dead pixels.

Send a note to [email protected] with a link to this thread and the folks there will get you a new strip.

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