Morse Code Translator with Arduino

You write in your computer, sends a message thought USB and Arduino translates it into a Morse code.

Just a Arduino board with a buzzer connected at the digital output 12 (one wire in the ground and the other in the 12).

Arduino

I tried to make the code as general as possible so you can easily adapt it for anthers ways of transmitting a Morse code. To do that you just need to rewrite a few functions.

                                                  +-------------------+
                                                  | 3) Interpretation |
                                                  +-------------------+
                                                  |   2) Translation  |
+-------------------+                             +-------------------+
|     Computer      |<========USB (Serial)=======>|     1) Reading    |
+-------------------+                             +-------------------+

Reads a character from Serial. Main function loop().
Translate a ascii char into a Morse code using a reference table. A letter 'K' becomes a string word "-.-". Function say_char().
Interpret the Morse word as light and sound. Mostly at function say_morse_word(). The Interpretation needs 5 functions to say all Morse words, dot(), dash(), shortgap(), mediumgap() and intragap().

For a more details on Morse code I strongly recommend the English Wikipedia article on it.

int led = 13;                   // LED connected to digital pin 13
int buzzer = 12;                // buzzer connected to digital pin 12
int unit = 50;                  // duration of a pulse
 
char * morsecode[] = {
    "-----",  // 0
    ".----",  // 1
    "..---",  // 2
    "...--",  // 3
    "....-",  // 4
    ".....",  // 5
    "-....",  // 6 
    "--...",  // 7
    "---..",  // 8
    "----.",  // 9
    "---...", // :
    "-.-.-.", // ;
    "",       // < (there's no morse for this simbol)
    "-...-",  // =
    "",       // > (there's no morse for this simbol)
    "..--..", // ?
    ".--._.", // @
    ".-",     // A
    "-...",   // B
    "-.-.",   // C
    "-..",    // D
    ".",      // E
    "..-.",   // F
    "--.",    // G
    "....",   // H
    "..",     // I
    ".---",   // J
    "-.-",    // K
    ".-..",   // L
    "--",     // M
    "-.",     // N
    "---",    // O
    ".--.",   // P
    "--.-",   // Q
    ".-.",    // R
    "...",    // S
    "-",      // T
    "..-",    // U
    "...-",   // V
    ".--",    // W
    "-..-",   // X
    "-.--",   // Y
    "--.."    // Z
};
 
void setup() {
  pinMode(led, OUTPUT);
  pinMode(buzzer, OUTPUT);
  Serial.begin(9600);
}
 
void say_morse_word(char * msg){
  int index = 0;
  while(msg[index]!='\0'){
    // say a dash
    if(msg[index]=='-'){
      dash();
    }
    // say a dot
    if(msg[index]=='.'){
      dot();
    }
    // gap beetween simbols
    intragap();
    index++;
  }
}
 
// beep
void beep(int time){
  int i;
  int t = 100; // period of the wav. bigger means lower pitch.
  int beepduration = (int)((float)time/t*1800);
  digitalWrite(led, HIGH);
  for(i=0;i<beepduration;i++){
    digitalWrite(buzzer, HIGH);
    delayMicroseconds(t);
    digitalWrite(buzzer, LOW);
    delayMicroseconds(t);
  }
  delay(time);
}
 
// silence
void silence(int time){
  digitalWrite(led, LOW);
  delay(time);
}
 
// general procedure for .
void dot() {
  beep(unit);
}
 
// general procedure for -
void dash() {
  beep(unit*3);
}
 
// gap between dots and dashes
void intragap() {
  silence(unit);
}
 
// gap between letters
void shortgap() {
  silence(3*unit);
}
 
// gap be  tween words
void mediumgap() {
  silence(7*unit);
}
 
void say_char(char letter){
  if((letter>='0')&&(letter<='Z')&&(letter!='<')&&(letter!='>')){
    Serial.print(morsecode[letter-'0']);
    Serial.print(' ');
    say_morse_word(morsecode[letter-'0']);
    shortgap();
  } else {
    if(letter==' '){
      Serial.print(" \\ ");
      mediumgap();
    }else{
      Serial.print("X");
    }
  }
}
 
void loop(){
  if(Serial.available()){
    say_char((char)Serial.read());
  }
}

Additionally you can put another function to say entire strings, like say_string("HELLO WORLD")

void say_string(char * asciimsg){
  int index = 0;
  char charac;
  charac = asciimsg[index];
  while(charac!='\0'){
    say_char(morsecode[charac-'0']);
    Serial.println(morsecode[charac-'0']);
    charac = asciimsg[++index];
    shortgap();
  }
}