#include <ESP32Servo.h>

// Pin definitions
#define TRIG_PIN 4   // Trig pin for HC-SR04
#define ECHO_PIN 5   // Echo pin for HC-SR04
#define SERVO_PIN 2  // Servo control pin

// Create Servo object
Servo myServo;

// Define constants
const int OPEN_ANGLE = 90;          // Servo open position
const int CLOSE_ANGLE = 0;          // Servo closed position
const int DISTANCE_THRESHOLD = 20; // Distance threshold in cm

void setup() {
  // Initialize serial communication
  Serial.begin(115200);

  // Configure pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  // Attach servo to the defined pin
  myServo.attach(SERVO_PIN);

  // Set initial servo position (closed)
  myServo.write(CLOSE_ANGLE);
}

void loop() {
  // Measure distance using the ultrasonic sensor
  long distance = measureDistance();
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Open or close the trash can based on distance
  if (distance > 0 && distance < DISTANCE_THRESHOLD) {
    myServo.write(OPEN_ANGLE); // Open the trash can
    delay(3000);               // Keep open for 3 seconds
  } else {
    myServo.write(CLOSE_ANGLE); // Close the trash can
  }

  delay(100); // Short delay for sensor stability
}

// Function to measure distance using HC-SR04
long measureDistance() {
  // Send a 10us pulse to TRIG_PIN
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Read the pulse width on ECHO_PIN
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance in cm
  long distance = duration * 0.034 / 2;

  return distance;
}