int soundPin = 13;
int dotDelay = 50;
int rate = 100;

void sound(int duration) {
  long time = millis();
  while (millis() - time < duration) {
    digitalWrite(soundPin, HIGH);
    delayMicroseconds(rate);
    digitalWrite(soundPin, LOW);
    delayMicroseconds(rate);
  }
}

void dot() {
  sound(dotDelay);
  delay(dotDelay);
}

void dash() {
  sound(3 * dotDelay);
  delay(dotDelay);
}

void morseLetter(char letter) {
  switch (letter) {
    case 'a': dot(); dash(); break;
    case 'b': dash(); dot(); dot(); dot(); break;
    case 'c': dash(); dot(); dash(); dot(); break;
    case 'd': dash(); dot(); dot(); break;
    case 'e': dot(); break;
    case 'f': dot(); dot(); dash(); dot(); break;
    case 'g': dash(); dash(); dot(); break;
    case 'h': dot(); dot(); dot(); dot(); break;
    case 'i': dot(); dot(); break;
    case 'j': dot(); dash(); dash(); dash(); break;
    case 'k': dash(); dot(); dash(); break;
    case 'l': dot(); dash(); dot(); dot(); break;
    case 'm': dash(); dash(); break;
    case 'n': dash(); dot(); break;
    case 'o': dash(); dash(); dash(); break;
    case 'p': dot(); dash(); dash(); dot(); break;
    case 'q': dash(); dash(); dot(); dash(); break;
    case 'r': dot(); dash(); dot(); break;
    case 's': dot(); dot(); dot(); break;
    case 't': dash(); break;
    case 'u': dot(); dot(); dash(); break;
    case 'v': dot(); dot(); dot(); dash(); break;
    case 'w': dot(); dash(); dash(); break;
    case 'x': dash(); dot(); dot(); dash(); break;
    case 'y': dash(); dot(); dash(); dash(); break;
    case 'z': dash(); dash(); dot(); dot(); break;
    case ' ': delay(7 * dotDelay); break;  // Пауза между словами
  }
  delay(2 * dotDelay);  // Пауза между буквами
}

void setup() {
  pinMode(soundPin, OUTPUT);
}

void loop() {
  char message[] = "hello world";
  for (int i = 0; i < strlen(message); i++) {
    morseLetter(message[i]);
  }
  delay(2000);
}