Use the LED to send out 'HELLO' in morse code. This is an example solution to assignment 2 which utilizes procedures.

Morse_Hello2.ino

//
// Morse_Hello2
//
// Use the LED to send out 'HELLO' in morse code.
// This is an example solution to assignment 2.
//
// The Circuit:
//     We use pin 13 as depending on the Arduino board 
//     (the Duinobot in our case), it has either:
//        - a built-in LED or,
//        - a built-in resistor so that you only need to add an LED.
//
//  NOTES: 
//      - The Duinobot has an LED so we do not have to add anything.
//      - See http://www.arduino.cc/en/Tutorial/Blink for the original
//        tutorial.
//
// Created: 3/18/2015
// By:      Chris Newton
// For:     Makers 10: Robotics and Prototyping
//
 
int dot = 250;                  // time in milliseconds for a dot
int dash = 3*dot;               // a dash is equal to 3 times a dot ('*' means multiply)
 
int ledPin = 13;                // on board LED connected to digital pin 13

//
// show_a_dot
//
// Procedure to do all the work of blinking a dot
//
void show_a_dot()
{
  digitalWrite(ledPin, HIGH);   // sets the LED on
  delay(dot);                   // waits for a dot
  digitalWrite(ledPin, LOW);    // sets the LED off
  delay(dot);                   // waits 3 dots
}
 
//
// show_a_dash
//
// Procedure to do all the work of blinking a dash
//
void show_a_dash()
{
  digitalWrite(ledPin, HIGH);   // sets the LED on
  delay(dash);                  // waits for a dash
  digitalWrite(ledPin, LOW);    // sets the LED off
  delay(dot);                   // waits again for a dot
}

// run once, when the sketch starts
void setup()                    
{
  pinMode(ledPin, OUTPUT);      // sets the digital pin as output
}

// show the letter 'H'
void show_H ()
{
  show_a_dot();
  show_a_dot();
  show_a_dot();
  show_a_dot();
  delay (2*dot);
}

void show_E ()
{
  show_a_dot();
  delay (2*dot);
}

void show_L ()
{
  show_a_dot();
  show_a_dash();
  show_a_dot();
  show_a_dot();
  delay (2*dot);
}

void show_O ()
{
  show_a_dash();
  show_a_dash();
  show_a_dash();
}

// show the word 'HELLO'
void show_HELLO ()
{
  show_H();
  show_E();
  show_L();
  show_L();
  show_O();
}

// run over and over again
void loop()                     
{
  // We are going to say 'HELLO' in morse code
  show_HELLO();
  
  delay(6*dot);                  // waits between words
}