int trigPin = 10;
int echoPin = 11;
int buzzer = 12;
int battery = 2; // Switch input pin

void setup() {
  Serial.begin(9600);
  pinMode(buzzer, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  //pinMode(switchPin, INPUT_PULLUP); // Use the internal pull-up resistor for the switch
}

void loop() {
  long duration, distance;
  //boolean switchState = digitalRead(switchPin);

 //if (switchState == LOW) {
    // Switch is pressed, perform distance measurement
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(1000);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distance = (duration / 2) / 29.1;

    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");

    if (distance <= 20) {
      digitalWrite(buzzer, HIGH);
    } else {
      digitalWrite(buzzer, LOW);
    }

    delay(10);
  }
//}