added builtin LED indication

Author: Inv3nt0r1

examples/Wiper/Wiper.ino

@@ -23,7 +23,7 @@ void setup()
   myservo.attach(9);  // attaches the servo on pin 9 to the servo object
   pinMode(button_pin, INPUT_PULLUP);   //declares the pin as digital input
   myservo.write(startpos);      // Initialize the servo wiper to start angle
-  pinMode(13, OUTPUT);
+  pinMode(LED_BUILTIN, OUTPUT); // to show the state of servo wiper
 }
 
 void loop()
@@ -33,7 +33,7 @@ void loop()
   if (digitalRead(button_pin) == LOW)  //Start the servo if the button is pressed and complete the
     //entire rotation regardless of button state later
   {
-    digitalWrite(13, HIGH);   //status that wiper servo is activated
+    digitalWrite(LED_BUILTIN, HIGH);   //status that wiper servo is activated
     for (int pos = startpos; pos <= endpos; pos += 1)  // goes from starting angle to end angle in steps of 1 degree
     {
       myservo.write(pos);              // tell servo to go to position in variable 'pos'
@@ -45,5 +45,5 @@ void loop()
       delay(5);                       // waits 15ms for the servo to reach the position
     }
   }
-  digitalWrite(13, LOW);  //status that wiper servo has stopped
+  digitalWrite(LED_BUILTIN, LOW);  //status that wiper servo has stopped
 }