Tangible User Interfaces - Fall 2011

Description

Use the Arduino to let a Light Emitting Diode (LED) blink according to a morse code.

If one would include a switch and a battery, then the device could to transmit a preset message to the person pressing the switch. Unfortunately we didn’t get a switch or button with the kit.

Any input text can be transformed to morse code using the website: http://morsecode.scphillips.com/jtranslator.html

Components Used

    Green LED
    Resistor 220 Ohm

Arduino Code

// Morse Code Blinking
// Letting a LED blink according to a morese code
// Code adapted by Kilian Moser, 08/31/2011

// Acknowledgements:
// Original morse code found at: http://www.maxkpage.com/blog/arduino-fun-with-leds-blink-morse-code/
// Text to Morse transformer foudn at: http://morsecode.scphillips.com/jtranslator.html

// The morse code the LED will blink for, in this case 'hello world'
char morse_code[] = ".... . .-.. .-.. ---    .-- --- .-. .-.. -.."; 

// constants won't change. 
// set pin numbers:
const int ledPin = 5; // the number of the LED pin
const int short_interval = 100; // interval at which to blink (milliseconds)
const int long_interval = 500; // interval at which to blink (milliseconds)
const int space_interval = 300; // interval at which to blink (milliseconds)
const int phrase_end_interval = 5000; // interval at which to blink (milliseconds)


// Variables that will change:
int ledState = LOW; // ledState used to set the LED
int letterSpot = 0; // Current letter you are testing in the morse code

void setup() {
  // set the digital pin as output:
  pinMode(ledPin, OUTPUT);
}


void loop()
{
  if(morse_code[letterSpot] == '.') {
    // if the LED is off turn it on:
    if (ledState == LOW)
      ledState = HIGH;

    digitalWrite(ledPin, ledState);
    delay(short_interval);
  }

  else if (morse_code[letterSpot] == '-') {

    // if the LED is off turn it on:
    if (ledState == LOW)
      ledState = HIGH;

    digitalWrite(ledPin, ledState);
    delay(long_interval);
  }

  else {
    //Space in the morse code
    letterSpot++;
    delay(space_interval);
  }

  if (ledState == HIGH) {
    // if the LED is on turn it off:
    ledState = LOW;
    digitalWrite(ledPin, ledState);
  }

  if (letterSpot < sizeof(morse_code) - 1) {
    // Move to the next letter in the morse code, unless you are at the end
    letterSpot++;
  }
  else {
    // Long pause at the end of the phrase before it starts over again
    letterSpot = 0;
    delay(phrase_end_interval);
  }


  // Small pause
  delay(short_interval);
}

Photo