Morse_Hello.ino

//
// Morse_Hello
//
// Use the LED to send out 'HELLO' in morse code.
// 
// 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.
//

int dot = 250;
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 dot
  digitalWrite(ledPin, LOW);    // sets the LED off
  delay(dot);                   // waits again for a dot
}

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


void loop()                     // run over and over again
{
  // We are going to say 'HELLO' in morse code
  
  // H
  show_a_dot();
  show_a_dot();
  show_a_dot();
  show_a_dot();
  delay (2*dot);

  // E
  show_a_dot();
  delay (2*dot);
  
  // L
  show_a_dot();
  show_a_dash();
  show_a_dot();
  show_a_dot();
  delay (2*dot);
  
  // L
  show_a_dot();
  show_a_dash();
  show_a_dot();
  show_a_dot();
  delay (2*dot);

  // O
  show_a_dash();
  show_a_dash();
  show_a_dash();
  
  delay(6*dot);                  // waits between words
}