   // or the SD library functions will not work. 
   pinMode(10, OUTPUT);
 
-  if (!SD.begin(10)) {
-    Serial.println("initialization failed!");
+  if (!SD.begin(chipSelect)) {
+    Serial.println("Initialization failed! ");
     return;
   }
   Serial.println("initialization done.");
-
-  // open the file. note that only one file can be open at a time,
-  // so you have to close this one before opening another.
-  file = SD.open("data.log", FILE_WRITE);
 
   // I2C Slave configuration
   Wire.begin(I2C_ADDRESS);                // join i2c bus with address #4

* - http://stackoverflow.com/questions/21073085/how-to-send-4-pot-values-via-i2c-from-arduino-to-arduino-how-to-differentiate-t
* About SD Cards:
* - https://learn.adafruit.com/adafruit-micro-sd-breakout-board-card-tutorial/format
* Some useful information about Aprilia RSV/SL bikes work: (See: http://www.aprilia-v60.com/index.php?topic=262315)
* - Speed sensor: purple/green wire=Vcc ~ 9V ? / grey/white: signal ~6.5V, falling to 0V
* - Engine pulses/revolution: 3 if read from the dashboard wire
* - Engine pulses/revolution: 6 if crank shaft sensor is used


unsigned long lastmillis;

const int chipSelect = 4;

uint8_t i2c_values[6];

