// Define pins
const int trigPin = 2;
const int echoPin = 3;
const int buzzerPin = 4;
const int buttonPin = 5;

// Variables
long duration;
int distance;
bool buzzerState = false;

void setup() {
  // Initialize pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP); // Use internal pull-up resistor

  Serial.begin(9600);
}

void loop() {
  // Send a pulse to the ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the pulse from the ultrasonic sensor
  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2) / 29.1; // Calculate distance in cm

  // Check if the button is pressed
  if (digitalRead(buttonPin) == LOW) {
    buzzerState = true; // Turn on buzzer if button is pressed
  } else {
    buzzerState = false; // Turn off buzzer if button is not pressed
  }

  // Control the buzzer
  if (buzzerState && distance < 200) {
    tone(buzzerPin, 1000); // Emit sound if object is within 20 cm and button is pressed
  } else {
    noTone(buzzerPin); // Turn off sound otherwise
  }

  // Print the distance to the Serial Monitor
  //Serial.print("Distance: ");
  //Serial.print(distance);
 // Serial.println(" cm");

  delay(100); // Delay for stability
}