Simple morse en- & decoding for Arduino (including LED Example)Build after the specs on http://en.wikipedia.org/wiki/Morse_code

LICENSE

Copyright (c) 2015 Matthias Esterl


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of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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furnished to do so, subject to the following conditions:


The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.


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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
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THE SOFTWARE.

morse.ino

//Define the LED Pin
#define PIN_OUT        9
//Define unit length in ms
#define UNIT_LENGTH    100

//Build a struct with the morse code mapping
static const struct {const char letter, *code;} MorseMap[] =
{
  { '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', "--.." },
  { ' ', "     " }, //Gap between word, seven units 
    
  { '1', ".----" },
  { '2', "..---" },
  { '3', "...--" },
  { '4', "....-" },
  { '5', "....." },
  { '6', "-...." },
  { '7', "--..." },
  { '8', "---.." },
  { '9', "----." },
  { '0', "-----" },
    
  { '.', ".-.-.-" },
  { ',', "--..--" },
  { '?', "..--.." },
  { '!', "-.-.--" },
  { ':', "---..." },
  { ';', "-.-.-." },
  { '(', "-.--." },
  { ')', "-.--.-" },
  { '"', ".-..-." },
  { '@', ".--.-." },
  { '&', ".-..." },
};

void doMorse(int pin, const char *string) {
  size_t i, j;
  
  for( i = 0; string[i]; ++i )
  {
    for( j = 0; j < sizeof MorseMap / sizeof *MorseMap; ++j )
    {
      if( toupper(string[i]) == MorseMap[j].letter )
      {
        emitMorse(pin, MorseMap[j].code);
        break;
      }
    }
    emitMorse(pin, "  "); //Add tailing space to separate the chars
  }
}

void emitMorse(int pin, const char *morseString) {
  for(int i=0; morseString[i]; i++)
  {
    switch( morseString[i] )
    {
      case '.': //dit
        digitalWrite( pin, HIGH );
        delay( UNIT_LENGTH );
        digitalWrite( pin, LOW );
        delay( UNIT_LENGTH );
          
        break;

      case '-': //dah
        digitalWrite( pin, HIGH );
        delay( UNIT_LENGTH*3 );
        digitalWrite( pin, LOW );
        delay( UNIT_LENGTH );
          
        break;

      case ' ': //gap
        delay( UNIT_LENGTH );
    }
  }
}

void setup()
{
  pinMode( PIN_OUT, OUTPUT );
  digitalWrite( PIN_OUT, LOW );
}

void loop()
{
  doMorse(PIN_OUT, "SOS ");
}

Fixed https://gist.github.com/madc/4474559#gistcomment-1904108
and https://gist.github.com/madc/4474559#gistcomment-2002007
and https://gist.github.com/madc/4474559#gistcomment-2002682

The last one I fixed by making the code emit the blinks as it runs through the input string, rather than doing a bunch of string concatenations and making a new string 4x bigger than the original. With the old code, it broke when I gave it an 8k string; now it works with 32k (and 65k failed to compile).

Oh, I also added a space between chars, for compliance to spec.