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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morse.ino

//Define the LED Pin
#define PIN_OUT        9
//Define unit length in ms
#define UNIT_LENGTH    250

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

void loop()
{
  String morseWord = encode( "SOS " );
    
  for(int i=0; i<=morseWord.length(); i++)
  {
    switch( morseWord[i] )
    {
      case '.': //dit
        digitalWrite( PIN_OUT, HIGH );
        delay( UNIT_LENGTH );
        digitalWrite( PIN_OUT, LOW );
        delay( UNIT_LENGTH );
          
        break;

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

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

String encode(const char *string)
{
  size_t i, j;
  String morseWord = "";
  
  for( i = 0; string[i]; ++i )
  {
    for( j = 0; j < sizeof MorseMap / sizeof *MorseMap; ++j )
    {
      if( toupper(string[i]) == MorseMap[j].letter )
      {
        morseWord += MorseMap[j].code;
        break;
      }
    }
    morseWord += " "; //Add tailing space to seperate the chars
  }

  return morseWord;  
}

String decode(String morse)
{
  String msg = "";
  
  int lastPos = 0;
  int pos = morse.indexOf(' ');
  while( lastPos <= morse.lastIndexOf(' ') )
  {    
    for( int i = 0; i < sizeof MorseMap / sizeof *MorseMap; ++i )
    {
      if( morse.substring(lastPos, pos) == MorseMap[i].code )
      {
        msg += MorseMap[i].letter;
      }
    }

    lastPos = pos+1;
    pos = morse.indexOf(' ', lastPos);
    
    // Handle white-spaces between words (7 spaces)
    while( morse[lastPos] == ' ' && morse[pos+1] == ' ' )
    {
      pos ++;
    }
  }

  return msg;
}

I believe your K is wrong: it should be -.- (see wikipedia)

The encoding for the period character { '.', "·–·–·–" } uses different dots and dashes than the other encodings.

What if I want to translate 2400 characters, I've try in many different ways but none of them it works.
It works until 1000, any Idea why and how to solve this?

Newbie comment: Could you add more comments to this code? Ignorant minds want to know. :)

@a18n: One thing you might want to understand, as a newbie, is that, he's building (declaring, and initialising) an array of structures at the top, not just a struct as the comment implies.

Does this work? I loaded it into my Teensy 3.6 and it does nothing.

Sorry, my mistake. Needed to change PIN_OUT to 13 on Teensy

Does anyone have the schematics for it?

Most everything here appears to be compliant with the spec described on Wikipedia. However, I believe to get "The letters of a word are separated by a space equal to three dots (one dash)", it should be morseWord += " "; //Add tailing space to seperate the chars, with two spaces.

I fixed the mentioned bugs, including (in my tests) the out-of-memory bug I think @tonytozoo was having.
https://gist.github.com/Erhannis/17de678c9b6ac4d75ffa585156f513b8
I also added another space between chars, for spec compliance. (Should be three dots worth of space between chars, rather than two.)

will this code auto detect the users speed - im doing a project with kids and we have som trouble with the fact that kids morse with different speed -

Super Newbie question:
I'm trying to get the morse code to work with an LED strip instead of the tiny LED on the Arduino. I want all of the LEDs on the strip to blink the morsecode simultaneously. But so far I can't get it to work.
I've added:

 **#include <FastLED.h>

 #define NUM_LEDS 300
 #define DATA_PIN 12
 CRGB leds[NUM_LEDS];**

and replaced pinMode(2, OUTPUT); with FastLED.addLeds<WS2811, DATA_PIN>(leds,NUM_LEDS);

But this does nothing. Any suggestions would be greatly appreciated!