#include <Servo.h>

Servo servo;
const int trigPin = 6; // Ultrasonic sensor trigger pin
const int echoPin = 5; // Ultrasonic sensor echo pin

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  servo.attach(3); // Servo attached to pin 3

  // Initialize serial communication
  Serial.begin(9600);
}

void loop() {
  int duration, distance;
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); // 10µs pulse for reliable trigger
  digitalWrite(trigPin, LOW);

  // Measure the pulse input in echo pin
  duration = pulseIn(echoPin, HIGH);

  // Calculate distance (half the duration divided by 29.1 from datasheet)
  distance = (duration/2) / 29.1;


  // Determine and display trash level indication
  if (distance < 400 && distance >= 300) {
    Serial.println("Bin is nearly full"); // Bin is nearly full
  } else if (distance > 100 && distance <= 300) {
    Serial.println("Bin is moderately full"); // Bin is moderately full
  } else if (distance > 0 && distance <= 100) {
    Serial.println("Bin is mostly empty"); // Bin is mostly empty
  } else {
    Serial.println("Bin is full");
  }

  // Servo control for dustbin lid
  if (distance <= 50 && distance >= 0) {
    servo.write(90); // Open lid (adjust angle as needed)
    delay(2000); // Keep lid open for 2 seconds
  } else {
    servo.write(0); // Close lid (adjust angle as needed)
  }

  delay(100); // Small delay to stabilize readings
}