#define BUZZER1 18
#define BUZZER2 5
#define BUZZER3 17
#define BUZZER4 16
#define sw 19

int i = 0;
int readSw1;
int checkSw1 = HIGH;

void setup() {
  Serial.begin(9600);
  pinMode(sw, INPUT_PULLUP);
  pinMode(BUZZER1, OUTPUT);
  pinMode(BUZZER2, OUTPUT);
  pinMode(BUZZER3, OUTPUT);
  pinMode(BUZZER4, OUTPUT);
}

void loop() {
  readSw1 = digitalRead(sw);

  if (checkSw1 != readSw1) {
    if (readSw1 == LOW) {
      i++;
    }
    checkSw1 = readSw1;
    delay(50);
  }

  if (i == 1) {
    digitalWrite(BUZZER1, HIGH);
  } else if (i == 2) {
    digitalWrite(BUZZER2, HIGH);
  } else if (i == 3) {
    digitalWrite(BUZZER3, HIGH);
  } else if (i == 4) {
    digitalWrite(BUZZER4, HIGH);
  } else if (i == 5) {
    digitalWrite(BUZZER1, LOW);
    digitalWrite(BUZZER2, LOW);
    digitalWrite(BUZZER3, LOW);
    digitalWrite(BUZZER4, LOW);
  } else if (i == 6) {
    digitalWrite(BUZZER1, HIGH);
    digitalWrite(BUZZER2, HIGH);
  } else if (i == 7) {
    digitalWrite(BUZZER3, HIGH);
    digitalWrite(BUZZER4, HIGH);
  } else if (i == 8) {
    i = 1;
    delay(500);
  }
}