Is my WS2812B LED strip broken?

Hello,

I’m trying to run a blink test on my LED strip where a single red light moves down the entire strip but the test only works on the first 24 lights. The 25th light turns bright yellow as soon I plugin the microcontroller even though it’s not supposed to. The red light will move through the strip and end on the yellow light.

I am using a ESP8266 but the Arduino code is basically the same.

#define FASTLED_ESP8266_NODEMCU_PIN_ORDER
#include <FastLED.h>

// How many leds in your strip?
#define NUM_LEDS 86

// For led chips like WS2812, which have a data line, ground, and power, you just
// need to define DATA_PIN.  For led chipsets that are SPI based (four wires - data, clock,
// ground, and power), like the LPD8806 define both DATA_PIN and CLOCK_PIN
// Clock pin only needed for SPI based chipsets when not using hardware SPI
#define DATA_PIN 5
#define CLOCK_PIN 13

// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() { 
    FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);  // GRB ordering is assumed
    FastLED.setMaxPowerInVoltsAndMilliamps(3.3, 300);
    FastLED.setBrightness(25);
}

void loop() { 
  // Turn the LEDs on, one at a time.
  for(int i=0; i<NUM_LEDS; i++) {
    leds[i] = CRGB::Red;
    FastLED.show();
    delay(250);
    // Now turn the LED off, then pause
    leds[i] = CRGB::Black;
    FastLED.show();
    delay(250);
  }
}

OK, that certainly sounds like a faulty LED.

How about a photo or two of the strip, taken in outside daylight (not in direct sunlight) and fully focused so we can actually see the LEDs themselves? Then we can suggest what surgery may be appropriate. :grinning:

I have the data being fed in from the bottom right and it just goes around the strip until it ends at the bottom left. The 25th LED is the first LED after the upper right corner.

I soldered the strips together pretty roughly but it was working perfectly fine until a day ago.

Ah! So the problem is indeed at a structural point. :grinning:

First guess is that one line or other has lifted the foil from the strip. Test the continuity of the ground, 5 V and data (next to each chip) with your multimeter. :sunglasses:

namarang:
You can connect all 24 lights in series so that each of the 24 LEDs lights up red.

No you can’t. These are addressable LEDs.

Those joints at the corner look bad. When solder goes into a ball like that then it is not making proper contact. Either the soldering iron was not hot enough or you did not leave it on the joint long enough so that the solder flows.

Are you wired as thus ?

My wiring is similar to the diagram with some differences. I'm using a 470uF capacitor and a 510 ohm resistor. Also the LED strip is being powered by the ESP8266 which is being powered by a USB cable.

kylekam:
Hello,

I'm trying to run a blink test on my LED strip where a single red light moves down the entire strip but the test only works on the first 24 lights. The 25th 2048 light turns bright yellow as soon I plugin the microcontroller even though it's not supposed to. The red light will move through the strip and end on the yellow light.

I am using a ESP8266 but the Arduino code is basically the same.

The problem is at a structural point.