/*
Radio Fox Tranmitter
by Nathanael Wilson

This transmits a long tone, followed by a call in morse code.
It then waits an ammount of time then transmits it again.
This transmits by connecting to a radio's ptt and mic input.

*/
#define tonehz 300 //the aproxamite frequency of the tones in hz, in reality it will be a tad lower.
#define dit 64 //the length of the dit in milliseconds. The dah and pauses are derived from this.
#define rest 60000 //the ammount of time between transmits in milliseconds
#define longlength 15000 //length of long tone in milliseconds
#define tx 11 //the pin of the board then keys the radio
#define audio 12 //the pin of the board then outputs the audio
int code[] = { 1, 1, 1, 0, 2, 2, 2, 0, 1, 1, 1, 0 }; // 1 id dih, 2 is dah, 0 is pause
int codelength = sizeof(code) / 2; //Divide the length that the array responds with by 2.
//Not sure why it returns 2 times the ammaount of info stored, but it does.
int length;
int duration;
int note = 1000000 / tonehz; //converts the frquency into period
void setup(){ //set the pins to output mode
  pinMode(tx, OUTPUT); 
  pinMode(audio, OUTPUT);
  pinMode(13, OUTPUT); //this is to see how the code looks with an led
}
void loop(){
  digitalWrite(tx, HIGH); //starts the radio transmitting
  playtone(longlength);
  delay(250);
  playcode();
  digitalWrite(tx, LOW); //Stops the radio's transmission
  delay(rest);
}
void playtone(int note_duration){
  long elapsed_time = 0;
  if (note_duration > 0){
    digitalWrite(13, HIGH); //See when it is making a tone on the led
    while (elapsed_time < note_duration){
      digitalWrite(audio, HIGH);
      delayMicroseconds(note / 2);
      digitalWrite(audio, LOW);
      delayMicroseconds(note / 2);
      elapsed_time += note / 1000;
    }
    digitalWrite(13, LOW);
  }
  else{ //if it's a pause this will run
    delay(dit * 2);
  }
}
void playcode(){
  for (int i=0; i < codelength; i++){
    
    length = code[i];
    
    if (length == 0){ //See if it's a pause
      duration = 0;
    }
    else if (length == 1){ //See if it's a dit
      duration = dit;
    }
    else if (length == 2){ //See if it's a dah
      duration = dit * 3;
    }
    playtone(duration);
    delay(dit); //makes a pause between sounds, otherwise each letter would be continuous.
  }
}