#include <Servo.h>

const int trashTrigPin = 3;     // Ultrasonic sensor for trash level, trig pin
const int trashEchoPin = 2;    // Ultrasonic sensor for trash level, echo pin
const int peopleTrigPin = 12;    // Ultrasonic sensor for people detection, trig pin
const int peopleEchoPin = 13;   // Ultrasonic sensor for people detection, echo pin
const int servoPin = 11;          // Servo motor control pin
const int ledPin = 5;           // Red LED notification pin

Servo lidServo;

void setup() {
  Serial.begin(9600);
  pinMode(trashTrigPin, OUTPUT);
  pinMode(trashEchoPin, INPUT);
  pinMode(peopleTrigPin, OUTPUT);
  pinMode(peopleEchoPin, INPUT);
  pinMode(servoPin, OUTPUT);
  pinMode(ledPin, OUTPUT);

  lidServo.attach(servoPin);
}

void loop() {
  int trashLevel = getDistance(trashTrigPin, trashEchoPin);
  int peopleDistance = getDistance(peopleTrigPin, peopleEchoPin);

  // Blink the LED until trash level reduces below the threshold
  if (trashLevel < 7) {
    blinkLED(); 
  }

  // Open lid when people come close
  if (peopleDistance < 12) {
    openLid();`
    delay(5000);
    closeLid();
  }
}

int getDistance(int trigPin, int echoPin) {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  return pulseIn(echoPin, HIGH) * 0.034 / 2; // Convert echo time to centimeters
}

void openLid() {
  lidServo.write(180);
}

void closeLid() {
  lidServo.write(0); 
}

void blinkLED() {
    digitalWrite(ledPin, HIGH);
    delay(500);
    digitalWrite(ledPin, LOW);
    delay(500);
}