added toInt() function to WString

SD examples/datalogger/datalogger.pde

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+/*
+  SD card datalogger
+ 
+ This example shows how to log data from three analog sensors 
+ to an SD card using the SD library.
+ 	
+ The circuit:
+ * analog sensors on analog ins 0, 1, and 2
+ * SD card attached to SPI bus as follows:
+ ** MOSI - pin 11
+ ** MISO - pin 12
+ ** CLK - pin 13
+ ** CS - pin 4
+ 
+ created  24 Nov 2010
+ by Tom Igoe
+ 
+ This example code is in the public domain.
+ 	 
+ */
+
+#include <SD.h>
+
+// On the Ethernet Shield, CS is pin 4. Note that even if it's not
+// used as the CS pin, the hardware CS pin (10 on most Arduino boards,
+// 53 on the Mega) must be left as an output or the SD library
+// functions will not work.
+const int chipSelect = 4;
+
+void setup()
+{
+  Serial.begin(9600);
+  Serial.print("Initializing SD card...");
+  
+  // see if the card is present and can be initialized:
+  if (!SD.begin(chipSelect)) {
+    Serial.println("Card failed, or not present");
+    // don't do anything more:
+    return;
+  }
+  Serial.println("card initialized.");
+}
+
+void loop()
+{
+  // make a string for assembling the data to log:
+  String dataString = "";
+
+  // read three sensors and append to the string:
+  for (int analogPin = 0; analogPin < 3; analogPin++) {
+    int sensor = analogRead(analogPin);
+    dataString += String(sensor);
+    if (analogPin < 2) {
+      dataString += ","; 
+    }
+  }
+
+  // open the file:
+  File dataFile = SD.open("datalog.txt", true, true);
+
+  // if the file is available, write to it:
+  if (dataFile) {
+    dataFile.println(dataString);
+    dataFile.close();
+    // print to the serial port too:
+    Serial.println(dataString);
+  }  
+  // if the file isn't open, pop up an error:
+  else {
+    Serial.println("error opening datalog.txt");
+  } 
+}
+
+
+
+
+
+
+
+
+