//Morse Code Binary Tree
//  Left child at 2n+1
// Right child at 2n+2
//         <.|->
//      .E       -T
//    .I  -A   .N  -M
//RX
const char MorseTree[] = {  '\0', 'E', 'T', 'I', 'A', 'N', 'M', 'S',
                            'U', 'R', 'W', 'D', 'K', 'G', 'O', 'H',
                            'V', 'F', 'U', 'L', 'A', 'P', 'J', 'B',
                            'X', 'C', 'Y', 'Z', 'Q', '\0', '\0', '5',
                            '4', '\0', '3', '\0', '\0', '\0', '2', '\0',
                            '\0', '+', '\0', '\0', '\0', '\0', '1', '6',
                            '=', '/', '\0', '\0', '\0', '(', '\0', '7',
                            '\0', '\0', '\0', '8', '\0', '9', '0', '\0',
                            '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
                            '\0', '\0', '\0', '?', '_', '\0', '\0', '\0',
                            '\0', '"', '\0', '\0', '.', '\0', '\0', '\0',
                            '\0', '@', '\0', '\0', '\0', '\0', '\0', '\0',
                            '-', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
                            '\0', ';', '!', '\0', ')', '\0', '\0', '\0',
                            '\0', '\0', ',', '\0', '\0', '\0', '\0', ':',
                            '\0', '\0', '\0', '\0', '\0', '\0', '\0'
                         };

int val = 0; // A Variable to Store the Light Value from the LDR
int ctrHigh = 0;
int ctrLow = 0;
int codePtr = 0;
int dotLen = 400;
/**********************************************/
//TX
const char* MorseTable[] = {
  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
  //space, !, ", #, $, %, &, '
  NULL, "-.-.--", ".-..-.", NULL, NULL, NULL, NULL, ".----.",
  // ( ) * + , - . /
  "-.--.", "-.--.-", NULL, ".-.-.", "--..--", "-....-", ".-.-.-", "-..-.",
  // 0 1 2 3 4 5 6 7
  "-----", ".----", "..---", "...--", "....-", ".....", "-....", "--...",
  // 8 9 : ; < = > ?
  "---..", "----.", "---...", "-.-.-.", NULL, "-...-", NULL, "..--..",
  // @ 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 [ \ ] ^ _
  "-..-", "-.--", "--..", NULL, NULL, NULL, NULL, "..--.-",
  // ' a b c d e f g
  NULL, ".-", "-...", "-.-.", "-..", ".", "..-.", "--.",
  // h i j k l m n o
  "....", "..", ".---", "-.-", ".-..", "--", "-.", "---",
  // p q r s t u v w
  ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--",
  // x y z { | } ~ DEL
  "-..-", "-.--", "--..", NULL, NULL, NULL, NULL, NULL,
};
int dotLength = 50; //time in mS
int dashLength = dotLength * 2;
void setup() {
  // put your setup code here, to run once:
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(A1, OUTPUT);
  digitalWrite(13, HIGH);
  digitalWrite(A1, LOW);
  Serial.begin(9600);
  Serial.print(codePtr);
}
void loop() {
  char ch;
  if (Serial.available()) {
    ch = Serial.read();
    flashDashDot(MorseTable[ch]);
    delay(dotLength * 2);

  }
  RX();
}
void flashDashDot(const char * morseCode)//TX
{
  int i = 0;
  while (morseCode[i] != 0)
  {
    if (morseCode[i] == '.') {
      dot();
    } else if (morseCode[i] == '-') {
      dash();
    }
    i++;
  }
}
void dot()
{
  digitalWrite(12, HIGH);
  delay(dotLength);
  digitalWrite(12, LOW);
  delay(dotLength);
}
void dash()
{
  digitalWrite(12, HIGH);
  delay(dashLength);
  digitalWrite(12, LOW);
  delay(dotLength);
}
void space() {
  digitalWrite(12, HIGH);
  delay(150);
  digitalWrite(12, LOW);
  delay(150);
}
void RX() {
  val = analogRead(0);
  if (val >= 10)
  {
    ctrHigh++;
    ctrLow = 0;
  } else {
    ctrLow++;
    if ((ctrHigh >= dotLen) && (ctrHigh < dotLen * 2)) {
      codePtr = (2 * codePtr) + 1;
    } else if (ctrHigh >= dotLen * 2) {
      codePtr = (2 * codePtr) + 2;
    }
    else {
      if (ctrLow == dotLen * 2) {
        Serial.print(MorseTree[codePtr]);
        codePtr = 0;
      }
    }
    ctrHigh = 0;
  }
}