Bell/bell.ino

# define BELL_COUNT 4
# define IN_A 1
# define OUT_A 0
# define IN_B 4
# define OUT_B 2

void setup() {                
   pinMode(1, OUTPUT); //LED on Model A   
   pinMode(OUT_A, OUTPUT);
   pinMode(OUT_B, OUTPUT);
   pinMode(IN_A, INPUT);
   pinMode(IN_B, INPUT);
   digitalWrite(OUT_A, HIGH);
   digitalWrite(OUT_B, HIGH);
 }

 // the loop routine runs over and over again forever:
 void loop() {
   if(digitalRead(IN_A)) {
     bell(OUT_A);
   }
   if(digitalRead(IN_B)) {
     bell(OUT_B);
   }
  } 

  void bell(int pin) { 
    for(int i=0;i<BELL_COUNT;i++) {
      digitalWrite(pin, LOW);
      delay(2000);
      digitalWrite(pin, HIGH);
      if(i < BELL_COUNT-1) {
        delay(3000);
      }
    }
  }