diff --git a/examples/BlinkUsingCustomTask/BlinkUsingCustomTask.ino b/examples/BlinkUsingCustomTask/BlinkUsingCustomTask.ino
index aa269f3..0f93282 100644
--- a/examples/BlinkUsingCustomTask/BlinkUsingCustomTask.ino
+++ b/examples/BlinkUsingCustomTask/BlinkUsingCustomTask.ino
@@ -2,9 +2,10 @@
 // This demonstrates the use of the custom Task object feature of Task library
 // It will use a custom task to blink a LED repeatedly, 
 
+#include <Arduino.h>
 
 // Pin 13 has an LED connected on most Arduino boards.
-#define LedPin 13
+#define LedPin 13 // BUILTIN_LED
 
 // include libraries
 #include <Task.h>
diff --git a/examples/BlinkUsingTaskFunction/BlinkUsingTaskFunction.ino b/examples/BlinkUsingTaskFunction/BlinkUsingTaskFunction.ino
index dbffdc0..6c456a3 100644
--- a/examples/BlinkUsingTaskFunction/BlinkUsingTaskFunction.ino
+++ b/examples/BlinkUsingTaskFunction/BlinkUsingTaskFunction.ino
@@ -3,11 +3,11 @@
 // It will use two FunctionTasks to to blink a LED repeatedly, by alternating 
 // which task is active and flpping the state of the LED pin
 
-
+#include <Arduino.h>
 #include <Task.h>
 
 // Pin 13 has an LED connected on most Arduino boards.
-int ledPin = 13;
+int ledPin = 13; // BUILTIN_LED
 
 TaskManager taskManager;
 
diff --git a/examples/BlinkUsingTaskMacros/BlinkUsingTaskMacros.ino b/examples/BlinkUsingTaskMacros/BlinkUsingTaskMacros.ino
index 8a3142f..9118e61 100644
--- a/examples/BlinkUsingTaskMacros/BlinkUsingTaskMacros.ino
+++ b/examples/BlinkUsingTaskMacros/BlinkUsingTaskMacros.ino
@@ -3,6 +3,8 @@
 // It will use a custom tasks defined using the helper macros to to blink
 // a LED repeatedly, 
 
+#include <Arduino.h>
+
 // include libraries
 #include <Task.h>
 
diff --git a/examples/BlinkUsingTaskMacros/taskBlinkLed.h b/examples/BlinkUsingTaskMacros/taskBlinkLed.h
index 24aa887..27f5365 100644
--- a/examples/BlinkUsingTaskMacros/taskBlinkLed.h
+++ b/examples/BlinkUsingTaskMacros/taskBlinkLed.h
@@ -1,6 +1,6 @@
 
 // Pin 13 has an LED connected on most Arduino boards.
-#define ledPin 13
+#define ledPin 13 // BUILTIN_LED
 
 TASK_DECLARE_BEGIN(TaskBlinkLed)
 // put member variables here that are scoped to this object
diff --git a/examples/ButtonInterrupt/ButtonInterrupt.ino b/examples/ButtonInterrupt/ButtonInterrupt.ino
index fb951ef..299b271 100644
--- a/examples/ButtonInterrupt/ButtonInterrupt.ino
+++ b/examples/ButtonInterrupt/ButtonInterrupt.ino
@@ -16,8 +16,10 @@
 //
 // usefull information is sent to the serial monitor
 
+#include <Arduino.h>
+
 // Pin 13 has an LED connected on most Arduino boards.
-#define LedPin 13
+#define LedPin 13 // BUILTIN_LED
 #define AButtonPin 4 // almost any io pin
 #define BButtonPin 5 // almost any io pin
 
diff --git a/examples/ButtonTask/ButtonTask.ino b/examples/ButtonTask/ButtonTask.ino
index 875b8b6..1cf30e2 100644
--- a/examples/ButtonTask/ButtonTask.ino
+++ b/examples/ButtonTask/ButtonTask.ino
@@ -8,8 +8,10 @@
 // the other button turn off the on board led when it is released
 // Both will send usefull information to the serial monitor
 
+#include <Arduino.h>
+
 // Pin 13 has an LED connected on most Arduino boards.
-#define LedPin 13
+#define LedPin 13 // BUILTIN_LED
 #define AButtonPin 4
 #define BButtonPin 5
 
diff --git a/examples/MessageTask/MessageTask.ino b/examples/MessageTask/MessageTask.ino
index 98cf7de..9e57ad3 100644
--- a/examples/MessageTask/MessageTask.ino
+++ b/examples/MessageTask/MessageTask.ino
@@ -10,6 +10,7 @@
 //
 // Usefull information will be sent to the serial monitor
 
+#include <Arduino.h>
 
 #define AButtonPin 4
 #define BButtonPin 5