SD Card Shield

No Arduino IDE, compilar e enviar o seguinte código (que está disponível em File-> Examples-> SD-> ReadWrite), e aguardar os resultados:

/*  
 SD card read/write  
 This example shows how to read and write data to and from an SD card file        
 The circuit:  
 * SD card attached to SPI bus as follows:  
 ** MOSI - pin 11  
 ** MISO - pin 12  
 ** CLK - pin 13  
 ** CS - pin 4  
 created  Nov 2010  
 by David A. Mellis  
 updated 2 Dec 2010  
 by Tom Igoe  
 This example code is in the public domain.  
 */
#include <SD.h>  
File myFile;  
void setup()  
{  
  Serial.begin(9600);  
  Serial.print("Initializing SD card...");  
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.  
  // Note that even if it's not used as the CS pin, the hardware SS pin   
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output   
  // or the SD library functions will not work.   
  pinMode(10, OUTPUT);  
  if (!SD.begin(4)) {  
    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.  
  myFile = SD.open("test.txt", FILE_WRITE);  
  // if the file opened okay, write to it:  
  if (myFile) {  
    Serial.print("Writing to test.txt...");  
    myFile.println("testing 1, 2, 3.");  
    // close the file:  
    myFile.close();  
    Serial.println("done.");  
  } 
  else {  
    // if the file didn't open, print an error:  
    Serial.println("error opening test.txt");  
  }  
  // re-open the file for reading:  
  myFile = SD.open("test.txt");  
  if (myFile) {  
    Serial.println("test.txt:");  
    // read from the file until there's nothing else in it:  
    while (myFile.available()) {  
      Serial.write(myFile.read());  
    }  
    // close the file:  
    myFile.close();  
  } 
  else {  
    // if the file didn't open, print an error:  
    Serial.println("error opening test.txt");  
  }  
}  
void loop()  
{  
  // nothing happens after setup  
}  

http://shieldlist.org/