// play monophon sounds on the tesla coil
//
// receives uint16s from serial which specify the tone length in microseconds (0 for silence)


int pin1 = 4;
int pin2 = 5;
unsigned int tonelength = 0;
float high_factor = .2;

void setup () {
  pinMode(pin1, OUTPUT);
  pinMode(pin2, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  while ( true ) {
  if ( Serial.available() > 1 ) {
    tonelength = Serial.read() << 8;
    tonelength |= Serial.read();
    Serial.print("New tonelength: ");
    Serial.println(tonelength);
  }
  if ( tonelength == 0 )
    delayMicroseconds(10);
  else
    beep(tonelength);
  }
}

void beep(long usecs) {
  high();
  delayMicroseconds(usecs*high_factor);
  low();
  delayMicroseconds(usecs*(1-high_factor));
}

void high() {
  digitalWrite(pin1, HIGH);
  digitalWrite(pin2, HIGH);
}

void low() {
  digitalWrite(pin1, LOW);
  digitalWrite(pin2, LOW);
}

long freq (double f) {
  // convert frequency to tonelength
  return 1000000/f;
}