OpenLog (SparkFun) als Datenspeicher verwenden

Ich habe folgenden Sketch verwendet um einmal zu schauen ob der DataLogger üverhaupt funktioniert:

int ledPin = 13; //Status LED connected to digital pin 13

void setup()
{
  pinMode(ledPin, OUTPUT);

  //Serial.begin(9600); //9600bps is default for OpenLog
  Serial.begin(57600); //Much faster serial, used for testing buffer overruns on OpenLog
  //Serial.begin(115200); //Much faster serial, used for testing buffer overruns on OpenLog

  delay(1000); //Wait a second for OpenLog to init

  Serial.println();
  Serial.println("Run OpenLog Test");

  int testAmt = 10;
  //At 9600, testAmt of 4 takes about 1 minute, 10 takes about 3 minutes
  //At 57600, testAmt of 10 takes about 1 minute, 40 takes about 5 minutes
  //At 115200, testAmt of 30 takes about 1 minute
  //testAmt of 10 will push 111,000 characters/bytes. With header and footer strings, total is 111,052

  //Each test is 100 lines. 10 tests is 1000 lines (11,000 characters)
  for(int numofTests = 0 ; numofTests < testAmt ; numofTests++)
  {
    //This loop will print 100 lines of 110 characters each
    for(int k = 33; k < 43 ; k++)
    {
      //Print one line of 110 characters with marker in the front (markers go from '!' to '*')
      Serial.write(k); //Print the ASCII value directly: ! then " then #, etc
      Serial.println(":abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-!#");
      //delay(50);

      //Then print 9 lines of 110 characters with new line at the end of the line
      for(int i = 1 ; i < 10 ; i++)
      {
        Serial.print(i, DEC);
        Serial.println(":abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-!#");
        //delay(50);
      }

      if(digitalRead(ledPin) == 0) //Turn the status LED on/off as we go
        digitalWrite(ledPin, HIGH);
      else
        digitalWrite(ledPin, LOW);
    }
  } //End numofTests loop

  unsigned long totalCharacters = (long)testAmt * 100 * 110;
  Serial.print("Characters pushed: ");
  Serial.println(totalCharacters);
  Serial.print("Time taken (s): ");
  Serial.println(millis()/1000);
  Serial.println("Done!");
}

void loop()
{
  //Blink the Status LED because we're done!
  digitalWrite(ledPin, HIGH);
  delay(100);
  digitalWrite(ledPin, LOW);
  delay(1000);
}

Es klappt bis hierin wunderbar.
Nun ist auf der SD Karte aber nichts gespeichert...
Es befinden sich auf der Sd Karte zwei .txt's. Das eine heißt Config und beinhaltet folgendes:

9600,26,3,0,1,1,0
baud,escape,esc#,mode,verb,echo,ignoreRX

Das andere heißt LOG00261 und beinhalten nichts.
Wie speichere ich die Daten auf dem SD leser ab ?