WS2811 Adalight Ambibox Arduino

#include "FastLED.h"
#define NUM_LEDS 50
#define DATA_PIN 6
#define serialRate 500000
static const uint8_t prefix[] = {'A', 'd', 'a'};

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

void setup() {
      FastLED.addLeds<WS2811, DATA_PIN, RGB>(leds, NUM_LEDS);
      Serial.begin(serialRate);
      Serial.print("Ada\n");
}

void loop() {
      for(int i = 0; i < sizeof(prefix); ++i){
            while (!Serial.available());
            if(prefix[i] != Serial.read())
            return;
      }
      while(Serial.available() < 3);
      int highByte = Serial.read();
      int lowByte  = Serial.read();
      int checksum = Serial.read();
      if (checksum != (highByte ^ lowByte ^ 0x55)){
            return;}

      uint16_t ledCount = ((highByte & 0x00FF) << 8 | (lowByte & 0x00FF) ) + 1;
      if (ledCount > NUM_LEDS){
            ledCount = NUM_LEDS;}

      for (int i = 0; i < ledCount; i++){
            while(Serial.available() < 3);
            leds[i].r = Serial.read();
            leds[i].g = Serial.read();
            leds[i].b = Serial.read();}
            FastLED.show();
}