Use LED_BUILTIN

Modified blink example to use LED_BUILTIN. In this way it works out of the box on each board

Author: agdl

build/shared/examples/01.Basics/Blink/Blink.ino

@@ -2,28 +2,31 @@
   Blink
   Turns on an LED on for one second, then off for one second, repeatedly.
 
-  Most Arduinos have an on-board LED you can control. On the Uno and
-  Leonardo, it is attached to digital pin 13. If you're unsure what
-  pin the on-board LED is connected to on your Arduino model, check
+  Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO 
+  it is attached to digital pin 13, on MKR1000 on pin 6. 
+  If you're unsure what pin the on-board LED is connected to on your Arduino model, check
   the documentation at http://www.arduino.cc
 
   This example code is in the public domain.
 
   modified 8 May 2014
   by Scott Fitzgerald
- */
+  
+  modified 2 Sep 2016
+  by Arturo Guadalupi
+*/
 
 
 // the setup function runs once when you press reset or power the board
 void setup() {
-  // initialize digital pin 13 as an output.
-  pinMode(13, OUTPUT);
+  // initialize digital pin LED_BUILTIN as an output.
+  pinMode(LED_BUILTIN, OUTPUT);
 }
 
 // the loop function runs over and over again forever
 void loop() {
-  digitalWrite(13, HIGH);   // turn the LED on (HIGH is the voltage level)
-  delay(1000);              // wait for a second
-  digitalWrite(13, LOW);    // turn the LED off by making the voltage LOW
-  delay(1000);              // wait for a second
+  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
+  delay(1000);                       // wait for a second
+  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
+  delay(1000);                       // wait for a second
 }