Data Logging with SD Cards - Exploring Arduino: Tools and Techniques for Engineering Wizardry - page 291

//Set by default for the SD card library
//MOSI = pin 11
//MISO = pin 12
//SCLK = pin 13
//We always need to set the CS Pin
const int CS_PIN = 10;
//We set this high to provide power
const int POW_PIN =8;
void setup()
{
Serial.begin(9600);
Serial.println("Initializing Card");
//CS pin is an output
pinMode(CS_PIN, OUTPUT);
//Card will draw power from pin 8, so set it high
pinMode(POW_PIN, OUTPUT);
digitalWrite(POW_PIN, HIGH);
if (!SD.begin(CS_PIN))
{
Serial.println("Card Failure");
return;
}
Serial.println("Card Ready");
}
void loop()
{
long timeStamp = millis();
String dataString = "Hello There!";
//Open a file and write to it.
File dataFile = SD.open("log.csv", FILE_WRITE);
if (dataFile)
{
dataFile.print(timeStamp);
dataFile.print(",");
dataFile.println(dataString);
dataFile.close(); //Data isn't actually written until we
//close the connection!
//Print same thing to the screen for debugging
Serial.print(timeStamp);
Serial.print(",");
Serial.println(dataString);
}
else