const int dot_pin = 2;
const int dash_pin = 3;

char last_state = 'X';

void setup() {
  Serial.begin(115200); 

  pinMode(dot_pin, INPUT_PULLUP);
  pinMode(dash_pin, INPUT_PULLUP);
}

void loop() {
  char current_state = '0';
  if (digitalRead(dot_pin) == LOW) {
    current_state += 1;
  }
  if (digitalRead(dash_pin) == LOW) {
    current_state += 2;
  }
  
  if (current_state != last_state) {
    Serial.print(current_state);
    last_state = current_state;
  }
  delay(1); // Limit update rate under 1kHz
}