#define MorsePin 21

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(MorsePin, OUTPUT);
}


void dot() {
digitalWrite(MorsePin, HIGH);
delay(100);
digitalWrite(MorsePin, LOW);
delay(500);
}


void dash() {
digitalWrite(MorsePin, HIGH);
delay(750);
digitalWrite(MorsePin, LOW);
delay(250);
}

void loop() {
  // morse code for SOS 
  dot(); dot(); dot(); 
  delay(1000);

  dash(); dash(); dash();
  delay(1000);


  dot(); dot(); dot(); 
  delay(1000);


  delay(2500);
}