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One Strip Works, One Does Not
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Please be positive and constructive with your questions and comments.

One Strip Works, One Does Not

by hamachi on Fri Mar 09, 2018 11:21 am

I purchased two identical digital RGB LED strips. One of them worked fine with my test setup running strandtest on my Arduino Uno. Using the same test setup, the other strip was almost completely dark and non-functional: the first LED lit and the rest of the string was dark. When I tried the bad strip again it was the same except that a different single LED in the middle of the string was steady lit.

The working strip is consistently working fine. The bad strip is consistently bad. Because of this, it seems clear to me that there isn't anything wrong with my test setup or software, and that the fault is in the LED strip.

I placed two separate orders for the Adafruit NeoPixel Digital RGB LED Strip - Back 30 LED 1m, part number 2552. My first order was 10 February 2018, Invoice 1676802. When I received it I realized that it wasn't long enough, so I ordered an additional one. My second order was exactly the same product, on 02 March 2018, Invoice 1694781. I only started playing with these after the second strip arrived. I don't remember if the bad strip was the first one or the second one. I would like you to authorize a replacement.

I am running strandtest on an Arduino Uno. Here are my connections:
* Pin 6 on the Arduino connects to Din on the LED strip.
* 5V on the Arduino connects to the red wire on the LED strip.
* GND on the Arduino connects to the black wire on the LED strip.

Here is an image of my test setup:
IMG_3061.jpg
Test setup
IMG_3061.jpg (83.95 KiB) Viewed 277 times

hamachi
 
Posts: 4
Joined: Fri Mar 09, 2018 10:29 am

Re: One Strip Works, One Does Not

by hamachi on Fri Mar 09, 2018 11:25 am

My code is just strandtest, modified only to specify 30 LEDs.

Code: Select all | TOGGLE FULL SIZE
#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
  #include <avr/power.h>
#endif

#define PIN 6
#define LEDS 30

// Parameter 1 = number of pixels in strip
// Parameter 2 = Arduino pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_KHZ800  800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
//   NEO_KHZ400  400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)
//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
//   NEO_RGBW    Pixels are wired for RGBW bitstream (NeoPixel RGBW products)
Adafruit_NeoPixel strip = Adafruit_NeoPixel(LEDS, PIN, NEO_GRB + NEO_KHZ800);

// IMPORTANT: To reduce NeoPixel burnout risk, add 1000 uF capacitor across
// pixel power leads, add 300 - 500 Ohm resistor on first pixel's data input
// and minimize distance between Arduino and first pixel.  Avoid connecting
// on a live circuit...if you must, connect GND first.

void setup() {
  // This is for Trinket 5V 16MHz, you can remove these three lines if you are not using a Trinket
  #if defined (__AVR_ATtiny85__)
    if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
  #endif
  // End of trinket special code


  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
}

void loop() {
  // Some example procedures showing how to display to the pixels:
  colorWipe(strip.Color(255, 0, 0), 50); // Red
  colorWipe(strip.Color(0, 255, 0), 50); // Green
  colorWipe(strip.Color(0, 0, 255), 50); // Blue
//colorWipe(strip.Color(0, 0, 0, 255), 50); // White RGBW
  // Send a theater pixel chase in...
  theaterChase(strip.Color(127, 127, 127), 50); // White
  theaterChase(strip.Color(127, 0, 0), 50); // Red
  theaterChase(strip.Color(0, 0, 127), 50); // Blue

  rainbow(20);
  rainbowCycle(20);
  theaterChaseRainbow(50);
}

// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);
    strip.show();
    delay(wait);
  }
}

void rainbow(uint8_t wait) {
  uint16_t i, j;

  for(j=0; j<256; j++) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel((i+j) & 255));
    }
    strip.show();
    delay(wait);
  }
}

// Slightly different, this makes the rainbow equally distributed throughout
void rainbowCycle(uint8_t wait) {
  uint16_t i, j;

  for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel
    for(i=0; i< strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
    }
    strip.show();
    delay(wait);
  }
}

//Theatre-style crawling lights.
void theaterChase(uint32_t c, uint8_t wait) {
  for (int j=0; j<10; j++) {  //do 10 cycles of chasing
    for (int q=0; q < 3; q++) {
      for (uint16_t i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, c);    //turn every third pixel on
      }
      strip.show();

      delay(wait);

      for (uint16_t i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, 0);        //turn every third pixel off
      }
    }
  }
}

//Theatre-style crawling lights with rainbow effect
void theaterChaseRainbow(uint8_t wait) {
  for (int j=0; j < 256; j++) {     // cycle all 256 colors in the wheel
    for (int q=0; q < 3; q++) {
      for (uint16_t i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, Wheel( (i+j) % 255));    //turn every third pixel on
      }
      strip.show();

      delay(wait);

      for (uint16_t i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, 0);        //turn every third pixel off
      }
    }
  }
}

// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
  WheelPos = 255 - WheelPos;
  if(WheelPos < 85) {
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  }
  if(WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
  WheelPos -= 170;
  return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
}
Last edited by adafruit_support_bill on Sat Mar 10, 2018 10:17 am, edited 1 time in total.
Reason: Fixed [code] tags

hamachi
 
Posts: 4
Joined: Fri Mar 09, 2018 10:29 am

Re: One Strip Works, One Does Not

by dee_sap on Fri Mar 09, 2018 1:48 pm

It doesn't necessarily speak to the inconsistency between the two strands, but have you tried a different power setup? The 5V output on the Arduino is not nearly rated to output the roughly 2 Amps that meter of Neopixels can need at full power. Even lit at 1/3 power that meter could need much higher current than the Uno on USB power can safely provide. You might get more consistent results with a proper power supply. And you'll definitely be at less risk of frying your Arduino.

dee_sap
 
Posts: 8
Joined: Fri Feb 17, 2017 2:35 pm

Re: One Strip Works, One Does Not

by hamachi on Sat Mar 10, 2018 3:50 am

Fair question. To test this idea, I modified my test setup so that the LED strip was supplied by a 5V 2.5A power brick, separate from the Arduino power supply. The result was the same: the "good" strip performed flawlessly and the "bad" strip was, well, bad.

Thank you for the suggestion, which unfortunately didn't work.

hamachi
 
Posts: 4
Joined: Fri Mar 09, 2018 10:29 am

Re: One Strip Works, One Does Not

by caitlinsdad on Sat Mar 10, 2018 9:52 am

On the neopixel strip you should see direction arrows printed on it. They should be pointing away from the board to indicate data flow from the first neopixel to the end of the strip. If you got the strip with a connector already attached, sometimes that may be the cut strip from the end of a long reel and the connector has the data-out line in the connector. The arduino needs to feed a data-in or DI to the first neopixel on the strip. Take a closer look at the strip and you may need to connect to the data-in at the other end of the strip. Good luck.

caitlinsdad
 
Posts: 530
Joined: Fri Feb 24, 2012 4:23 pm

Re: One Strip Works, One Does Not

by adafruit_support_bill on Sat Mar 10, 2018 10:22 am

As caitlinsdad said, strips cut from the end of a reel will have the wires attached to the output end. When powered, you might get a random led lighting up. But the signal needs to be applied to the "DI" end, not the "DO". The arrows on the strip indicate the flow of data and should point away from where you connect the signal input.

First verify that you are connecting to the input end. If so, and the strip still does not work, please contact support@adafruit.com with a link to this thread for a replacement.

adafruit_support_bill
 
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Joined: Sat Feb 07, 2009 10:11 am

Re: One Strip Works, One Does Not

by hamachi on Sat Mar 10, 2018 1:27 pm

Thank you for the generous advice, and the speedy replies.

I confirm that I have been attaching to the data input side, on the strip that fails as well as the strip that works.

Both of my LED strips have black connectors at each end. The connector with the fixed "tooth" is on the input side, while the mating connector with the moving latch is on the output side. As my photo shows, my test setup uses a black connector with the moving latch, so it only mates to the input side.

Having completed this verification, I will proceed to send email to support. Evidently a link to this thread is a form of RMA :-)

hamachi
 
Posts: 4
Joined: Fri Mar 09, 2018 10:29 am

Re: One Strip Works, One Does Not

by adafruit_support_bill on Sat Mar 10, 2018 1:53 pm

Evidently a link to this thread is a form of RMA :-)

That is correct. :-)

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Posts: 69240
Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.