[solved] Can't control LED Strip with Arduino

Hello, I'm a total noob and am even failing to do the probably most basic thing ever.
I'm trying to control my ws2811 LEDs with my Arduino Nano atm and it doesn't work. The LED 12v is connected to a 12v power supply Ground is connected to the power supply and the ground pin on the Arduino Nano and the Data is connect to Digital Pin 3 on the Arduino and the LEDs even light up bright white but that's it. I tried to make them blink with the FastLED Libary Example program but the LEDs just stay white when I upload it, here is the program maybe I only defined a pin wrong or something like that. The strip has 1 Controller per 3 LEDs so I assumed I have to count the number of controllers so I defined NUM_LEDS as 2. And I connected the DI (DataIN) Pin of the LEDs to the Digital Pin 3

Below you can see how the circuit I created looks.

#include "FastLED.h"

// How many LEDs in your strip?
#define NUM_LEDS 2

// For led chips like Neopixels, 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
#define DATA_PIN 3
//#define CLOCK_PIN 13

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

void setup() { 
     // Uncomment/edit one of the following lines for your leds arrangement.
     // FastLED.addLeds<TM1803, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<TM1804, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<TM1809, DATA_PIN, RGB>(leds, NUM_LEDS);
      FastLED.addLeds<WS2811, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<WS2812, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<WS2812B, DATA_PIN, RGB>(leds, NUM_LEDS);
   // FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
     // FastLED.addLeds<APA104, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<UCS1903, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<UCS1903B, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<GW6205, DATA_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<GW6205_400, DATA_PIN, RGB>(leds, NUM_LEDS);
     
     // FastLED.addLeds<WS2801, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<SM16716, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<LPD8806, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<P9813, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<APA102, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<DOTSTAR, RGB>(leds, NUM_LEDS);

     // FastLED.addLeds<WS2801, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<SM16716, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<LPD8806, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<P9813, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
     // FastLED.addLeds<DOTSTAR, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
}

void loop() { 
 // Turn the LED on, then pause
 leds[0] = CRGB::Red;
 FastLED.show();
 delay(500);
 // Now turn the LED off, then pause
 leds[0] = CRGB::Black;
 FastLED.show();
 delay(500);
}

Hi,

For ws2811 led strip, NUM_LEDS sets to be 2 that means you have only 6 leds (~2 controllers) on the strip. Are you sure?

As my experience, you can set NUM_LEDS to equal or larger than the actual number of the controller of led strip.

Yes only 6 LEDs for now, I have cut off a "test-strip" of 6 LEDs/2Controllers

Problem solved everything works now.

what was the problem and hence, the solution so others who have this same problem can find an answer here..

I think it's so ridiculous to open a thread, expect support from people, but when you have to solution, you don't contribute by posting it lol

I’m having exactly the same issue.