char data[] = {"9005, 4400, 1600, 565"};
// Am ende des data-Arrays speichert der Compiler einen
// Nullterminator '\0' = 0 als Integerwert

unsigned int irRawData[300];

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  unsigned int bufferIndex = 0;
  for(int i = 0; data[i] != '\0'; i++) {
    if (data[i] >= '0' && data[i] <= '9')
      irRawData[bufferIndex] = irRawData[bufferIndex] * 10 + data[i] - '0';
    else if (data[i] == ' ')
             bufferIndex++;
  }

  for(int i = 0; i < 4; i++)
  {
    Serial.println(irRawData[i] * 2);
  }

}

void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
}