[SOLVED] LEDs won't light up

I currently bought this LED Strip here: https://www.amazon.com/BTF-LIGHTING-Addressable-Flexible-Silicone-Waterproof/dp/B01CP5PQU6?ref=ast_p_ep&th=1

I tried to control it using my arduino by connecting it to an external 12V Powersupply.
Ground of the LEDs and the arduino are connected to the ground of the powersupply.

And PIN 13 / 3 (I tried both) are connected to the Data Port of the LEDs.

#include <FastLED.h>

#define NUM_LEDS 12
#define LED_PIN 13

CRGB led[NUM_LEDS];

void setup() {
  FastLED.addLeds<NEOPIXEL, LED_PIN>(led, NUM_LEDS);
  for(int i = 0; i < NUM_LEDS; i++) {
    led[i] = CRGB(0, 0, 255);
  }
  FastLED.show();

}

void loop() {
  // put your main code here, to run repeatedly:

}

This is the code I tried to use, but unfortunately nothing happens, when I start it.
I also tried using this code:

#include "Adafruit_NeoPixel.h"

// DEFINITIONS

#define STARTCOLOR 0xFFFFFF  // LED colors at start
#define BLACK      0x000000  // LED color BLACK

#define DATAPIN    13        // Datapin
#define LEDCOUNT   12       // Number of LEDs used for boblight
#define BRIGHTNESS 90        // Max. brightness in %


Adafruit_NeoPixel strip = Adafruit_NeoPixel(LEDCOUNT, DATAPIN, NEO_GRB + NEO_KHZ800);

void setup()
{
  strip.begin();            // Init LED strand, set all black, then all to startcolor
  strip.setBrightness( (255 / 100) * BRIGHTNESS );

  setAllLEDs(BLACK, 0);
  setAllLEDs(STARTCOLOR, 5);
}

void loop() {}

void setAllLEDs(uint32_t color, int wait)
{
  for ( int Counter=0; Counter < LEDCOUNT; Counter++ )      // For each LED
  {
      strip.setPixelColor( Counter, color );      // .. set the color
      strip.show();                     // Show the LED color

      delay(50);                      // and wait before we do the next LED
  } // for Counter
} // setAllLEDs

I cannot figure out what to do. Don’t be confused by the Number of LEDs only being 12, I cut the LED stip at the mark after the 12th LED.
Is there a way to check if the LEDs are even working?

You should have a look at the examples here. The striop definition is different:

FastLED.addLeds<WS2811, PIN, GRB>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );

Unfortunately nothing happens..
Is there a way to test if my stripe is dead?

The strip is quite resistant, unless you supply it with very high voltage it should be working.
Did you try

FastLED.addLeds<WS2811, LED_PIN, GRB>(led, NUM_LEDS);

or even

FastLED.addLeds<WS2811, LED_PIN>(led, NUM_LEDS);

Otherwise, read the fastLED manual

Is there a way to test if my stripe is dead?

Only see if it works when yo wire it up correctly with the correct software.

Note that with that strip you can not controll individual LEDs only in groups of three. So if you have 12 actually LEDs then then number of LEDs you have to put in the software is 4.

Not that putting a bigger number is going to make any difference.

We need to see your code, with mistakes corrected and also a schematic and photograph of your wiring.

Common mistakes are not including a resistor and capacitor on the strip and sending the signal into the wrong end of the strip.

lesept:
The strip is quite resistant, unless you supply it with very high voltage it should be working.

NO No No
Do not apply a voltage bigger than 12V.

lesept:
Did you try

FastLED.addLeds<WS2811, LED_PIN, GRB>(led, NUM_LEDS);

or even

FastLED.addLeds<WS2811, LED_PIN>(led, NUM_LEDS);

Otherwise, read the fastLED manual

Yep I did. Unfortunately nothing helped.

Grumpy_Mike:
NO No No
Do not apply a voltage bigger than 12V.

Don’t fear… I did not applay a higher Voltage…

It seems that the stripe really is dead… But amazon is nice and sends me a new one… I hope that the new one will work just fine.

But thanks anyway!