added SerialLed example

usefulExamples/SerialLED/SerialLED.ino

@@ -0,0 +1,89 @@
+/* 
+ *  This sketch allows user to type "on" or "1" to turn the built in led on 
+ *  And "off" or "0" to turn the LED off. Any other input is ignored. 
+ *  Press Ctrl+Shift+M, the magnifiying glass button by close, 
+ *  or on the top menu Tools>Serial Monitor to show it. 
+ *  Enter commands in the top line.
+ */
+
+#define LED_PIN 13  // Sets LED_PIN to pin 13 (on board LED)
+// the setup function runs once when you press reset or power the board
+void setup() {
+  pinMode(LED_PIN, OUTPUT); // Change the mode of LED_PIN (13) to OUTPUT
+  Serial.begin(115200); // Starts Serial at 115200 baud rate
+  Serial.println("Ready for input"); // Prints a line to the console window
+}; // setup ends
+
+// the loop function runs over and over again forever
+void loop() {
+
+  // Here we make all the decisions, firstly if there is Serial.available()
+  // this will return true if something was entered in the console and 
+  // false if not so we don't need to do: if(Serial.available() == true)
+  if(Serial.available()){ 
+
+    // Create a new String type variable, in this case called stringToCompare, 
+    // It needs to be set to "" so we can add to it, Then let the user know 
+    // we got their message
+    String stringToCompare = "";  
+    Serial.print("got Serial "); 
+
+    // So, we determined there is Serial data, We want to read all of it, 
+    // The next part accomplishes this: while(Serial.available()) will repeat 
+    // provided that its Serial.available() is still true. 
+    while(Serial.available()){
+
+      // Here we create a variable, incomingChar, it holds a single character
+      // it is currently empty
+      // because incomingChar is a char type, anything we save to it will be
+      // converted to char type, which is a single alphanumeric character
+      char incomingChar;
+
+      // We read one byte from Serial, and save it as incomingChar
+      incomingChar = Serial.read(); 
+      // now, We add that single character (concatenate) to the end
+      // of stringToCompare 
+      stringToCompare.concat(incomingChar);
+      // and repeat until Serial.available() is false
+    } // while(Serial.available()) ends Serial.available() is false
+
+    // Convert stringToCompare to all upper case so on, On, ON and off, Off, OFF etc all work.
+    stringToCompare.toUpperCase(); 
+
+    // Removes all empty spaces from stringToCompare
+    stringToCompare.trim();
+
+    // Comparison time... The Serial.println(...) lines let the user know the 
+    // outcome of their console input
+    if(stringToCompare == ""){ // stringToCompare is still empty
+      Serial.println("Was Nothing, Not sure how");
+      // Do nothing 
+    } // if(stringToCompare == "") ends 
+
+    // This statement matches "ON" or "1", either work. 
+    else if( ( stringToCompare == "ON" ) or ( stringToCompare == "1" ) ){
+      Serial.print("stringToCompare was");
+      Serial.print(stringToCompare); // Print the variable
+      Serial.println(" Turning LED on!");
+      digitalWrite(LED_PIN, HIGH);   // turn the LED on (HIGH is the voltage level)
+    } // else if( ( stringToCompare == "ON" ) or ( stringToCompare == "1" ) ) ends
+
+    // Here is the statement for off, Again either "OFF" or "0" work
+    else if( ( stringToCompare == "OFF" ) or ( stringToCompare == "0" ) ){
+      Serial.print("stringToCompare was "); // Print the start
+      Serial.print(stringToCompare); // Print the variable
+      Serial.println(" , Turning LED off!"); // print the end, and end the line
+      digitalWrite(LED_PIN, LOW);    // turn the LED off by making the voltage LOW
+    } // else if( ( stringToCompare == "OFF" ) or ( stringToCompare == "0" ) ) ends
+
+    // Getting here means that we don't have an empty string, we definately have something
+    // but what we have is not "ON", "OFF", "1", or "0"
+    else {
+      Serial.println("Wrong input detected. Nothing happens");
+      // nothing happens here
+    } // else ends
+  } // if(Serial.available()) ends
+
+  // wait 1 second for serial input
+  delay(1000);// wait for a second before updating again. 
+}; // loop ends (well it just starts again but it finishes)