#include <Servo.h>

const int trigPin = 9; // Trig pin of the HC-SR04
const int echoPin = 10; // Echo pin of the HC-SR04
const int servoPin = 6; // Pin to which the servo motor is connected

Servo lidServo;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  lidServo.attach(servoPin);
}

void loop() {
  long duration, distance;
  
  // Triggering the ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reading the echo pin to calculate distance
  duration = pulseIn(echoPin, HIGH);
  
  // Calculating distance in cm
  distance = duration * 0.034 / 2;
  
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  
  // Opening the lid if an object or human is detected within 20cm
  if (distance < 10) {
    openLid();
    delay(2000); // Wait for 2 seconds before closing the lid
    closeLid();
  }
}

void openLid() {
  // Rotating the servo motor to open the lid
  lidServo.write(90); // Adjust the angle as per requirement
}

void closeLid() {
  // Rotating the servo motor to close the lid
  lidServo.write(0); // Adjust the angle as per requirement
}