Defective Dotstar Strip Moderators: adafruit_support_bill, adafruit

[Justice]

I recently was gifted a 4m black dotstar 60 LED strip along with the relevant 10A 5V power supply for Christmas by my parents. During testing the LED strip hasn't even been removed from the original reel that came in the anti-static bag. The barcode on the anti-static bag has the following information on:
Dotstar 60LED Black 4m
http://adafru.it/2239
P2239B
2018-03-27

I'm having an issue with the strip where one LED on the strip is constantly white and no LEDs after this one work at all. While it is difficult to see due to the camera not picking it up easily; here is a video demonstrating the problem: https://www.youtube.com/watch?v=yqrJdzU1MIo

This issue is present even when running the strandtest dotstar example with an arduino uno with the following setup parameters changed in the default code to allow hardware SPI and the whole strip to be tested:

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#define NUMPIXELS 60 // Number of LEDs in strip
// Here's how to control the LEDs from any two pins:
#define DATAPIN    4
#define CLOCKPIN   5
//Adafruit_DotStar strip = Adafruit_DotStar(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG);
// The last parameter is optional -- this is the color data order of the
// DotStar strip, which has changed over time in different production runs.
// Your code just uses R,G,B colors, the library then reassigns as needed.
// Default is DOTSTAR_BRG, so change this if you have an earlier strip.
// Hardware SPI is a little faster, but must be wired to specific pins
// (Arduino Uno = pin 11 for data, 13 for clock, other boards are different).
Adafruit_DotStar strip = Adafruit_DotStar(NUMPIXELS, DOTSTAR_BRG);


I am supplying the LEDs with power from a 10A 5V adaptor that appears to be working fine. I have also checked the voltage at the end of the strip between the ground and positive wires, and there is a 5V DC difference so the power is being applied correctly throughout the entire strip. The first set of LEDs light up successfully so I am certain that the clock and data pins are plugged in correctly.

Is there anything you can suggest me doing to attempt to solve my problem? Or will the strip have to be replaced in full?

Thanks and kind regards,
Alex

[adafruit_support_carter]

Go ahead and unroll the LED strip so we can get access to the apparently problematic pixel. Then try pressing down on the last pixel lit and the first pixel not lit and see if that changes anything.

And to double check your connections - can you post a photo showing how you have everything connected. It's not clear enough in the video.

[Justice]

Hi Carter,

For an overview of the wiring see the following image. For the purposes of taking these images I have temporarily unplugged the power to the strip (as my camera can't deal with fast changes in lighting) - when testing the strip this is obviously plugged in.


The Arduino Uno running the default test sketch "strandtest" with the code edited for this particular strip as shown in the original post (all code omitted is as in the default state). The Arduino is wired as follows with its own 5V 2A power supply.


The strip is wired to the Arduino as follows:
Arduino pin 11 -> Strip Data_In
Arduino pin 13 -> Strip Clock_In
Arduino GND -> Strip GND


The strip's wire colours and associated 5V, Clock_In, Data_In, and GND wires


The strip is powered by its own 5V 10A adaptor and is connected to the strip via a DC barrel jack to terminal convertor. I also have verified the voltage is being applied into the strip correctly with my multimeter by measuring between +5V and GND terminals before wiring the strip up. I also know the strip +5V and GND rails have power as I have measured the potential difference at the opposite end of the strip to where power is supplied.


I have attempted to press down the LED that is stuck on and it is warm to the touch after a few seconds (suggesting a short?) and nothing changes. Other LEDs while running the sketch do not feel as warm. I have tried pressing down the next LED that doesn't light up and it also doesn't change anything. I also tried flexing the cable slightly at the contacts for the Data and Clock connections between the LEDs and this also doesn't change anything just in case they're not connected properly and this doesn't fix the issue either.

Stuck LED

[adafruit_support_carter]

Thanks for all those awesome photos. That all looks fine. It's sure looking like a problematic pixel. One more quick check, let's try software SPI instead of hardware SPI just to see what happens. And maybe also try other pins on the UNO. As a start, you can just use the same pins and change to:

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    #define NUMPIXELS 60 // Number of LEDs in strip
    // Here's how to control the LEDs from any two pins:
    #define DATAPIN    11
    #define CLOCKPIN   13
    Adafruit_DotStar strip = Adafruit_DotStar(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_BRG);
    // The last parameter is optional -- this is the color data order of the
    // DotStar strip, which has changed over time in different production runs.
    // Your code just uses R,G,B colors, the library then reassigns as needed.
    // Default is DOTSTAR_BRG, so change this if you have an earlier strip.
    // Hardware SPI is a little faster, but must be wired to specific pins
    // (Arduino Uno = pin 11 for data, 13 for clock, other boards are different).
    //Adafruit_DotStar strip = Adafruit_DotStar(NUMPIXELS, DOTSTAR_BRG);


But then also swap to some other digital pins and make the necessary changes here:

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    #define DATAPIN    11
    #define CLOCKPIN   13


Just to see if there's any difference in the strip behavior.

[Justice]

Hi Carter,

Software SPI also has the stuck LED present regardless of the pins used. I have also tried checking the Uno by using a spare Mega I have lying around and it is still present then too.

[adafruit_support_carter]

Ok. Let's just replace it. It sounds like this was a gift. Do you have access to the original order information? Just the order number is all we need.

[Justice]

Thanks for your help, yes it was a gift from my parents. They're currently looking for the order number for me, I'll reply to this post when they find it.

[Justice]

Hi Carter,

The Order number is #1907612

Many thanks,
Alex

[adafruit_support_carter]

Cool. That the info you need. We can replace the strip (PID 2239). Send an email to support@adafruit.com with a link to this thread and they can get you one.