TI Launchpad Morse Code Generator

In electric circuit theory lab, we were assigned one of several projects using a TI MSP430 microcontroller. I chose to make a simple Morse code generator. I programmed the microcontroller code using Energia, which allows you to program the TI as if it were an Arduino.

This simplifies programming immensely, with functions for outputting square waves and blinking the onboard LED. In hindsight, if I were to re-do this project, I would use the millis()function instead of delay() to set the timing.

Components

Morse code generator schematic

1. TI Launchpad w/MSP430G2
2. Piezo buzzer

Show Code

int const DOT = 100;
int const DASH = DOT*3;
uint const FREQ = 500;
char const DOT_CHAR = '0';
int const PIN = 8;

// Morse code message to transmit
String message = "Your message here";

void setup() {
  Serial.begin(9600);

  // Convert to lower case for easy operation
  message.toLowerCase();

  // Initialize onboard LED
  pinMode(RED_LED, OUTPUT);
}

void loop() {
  // Delay to allow Log to open
  delay(2000);

  // Iterate through message string and convert each character to Morse code
  for (int i = 0; i < message.length(); i++) {
    toMorseCode(message.charAt(i));
  }

  // Wait 5 seconds before repeating message
  delay(5000);
  Serial.println("");
}

void toMorseCode(char c) {
  String sequence;

  switch(c) {
  case 'a':
  sequence = "01";
  break;
  case 'b':
  sequence = "1000";
  break;
  case 'c':
  sequence = "1010";
  break;
  case 'd':
  sequence = "100";
  break;
  case 'e':
  sequence = "0";
  break;
  case 'f':
  sequence = "0010";
  break;
  case 'g':
  sequence = "110";
  break;
  case 'h':
  sequence = "0000";
  break;
  case 'i':
  sequence = "00";
  break;
  case 'j':
  sequence = "0111";
  break;
  case 'k':
  sequence = "101";
  break;
  case 'l':
  sequence = "0100";
  break;
  case 'm':
  sequence = "11";
  break;
  case 'n':
  sequence = "10";
  break;
  case 'o':
  sequence = "111";
  break;
  case 'p':
  sequence = "0110";
  break;
  case 'q':
  sequence = "1101";
  break;
  case 'r':
  sequence = "010";
  break;
  case 's':
  sequence = "000";
  break;
  case 't':
  sequence = "1";
  break;
  case 'u':
  sequence = "001";
  break;
  case 'v':
  sequence = "0001";
  break;
  case 'w':
  sequence = "011";
  break;
  case 'x':
  sequence = "1001";
  break;
  case 'y':
  sequence = "1011";
  break;
  case 'z':
  sequence = "1100";
  break;
  case ' ':
  break;
  }

  // Write out current letter
  Serial.print(c);

  // Now, translate sequence to blinks and audio. Iterate through String sequence, where a "0" is a dot and a "1" is a   dash.
  for (int i = 0; i < sequence.length(); i++) {
    if (sequence.charAt(i) == DOT_CHAR) {
      blink(DOT);
    } else {
      blink(DASH);
    }
    // Pause between dots or dashes
    delay(DASH);
  }

  // Delay between letters is equal to two dashes
  delay(DASH*2);
}

void blink(int duration) {
  digitalWrite(RED_LED, HIGH);
  tone(PIN, FREQ);
  delay(duration);
  digitalWrite(RED_LED, LOW);
  noTone(PIN);
}