/*
-------------------------------------------------------------------------
Smart Parking System

Components:
 1) Arduino UNO (1 Nos)
 2) Ultrasonic Sensor (3 Nos)
 3) IR Sensor (1 Nos)
 4) LCD display (1 Nos)
 5) Servo Motor (1 Nos)
 6) Red Led (3 Nos)
 7) Green Led (3 Nos)

Author: Priyadharshini H
Date: 24-10-2023

Github: itzpriya 
-------------------------------------------------------------------------
*/

#include <LiquidCrystal.h>
#include <Servo.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

#define t1 10
#define t2 9
#define t3 8

#define IR_SENSOR_PIN 7
#define SERVO_PIN 6

#define GREEN_LED1 A0
#define GREEN_LED2 A2
#define GREEN_LED3 A4

#define RED_LED1 A1
#define RED_LED2 A3
#define RED_LED3 A5

Servo servoMotor;
int distanceThreshold = 150;

void setup() {
  lcd.begin(16,2);
  lcd.setCursor(0,0);
  
  pinMode(IR_SENSOR_PIN, INPUT_PULLUP);
  
  pinMode(GREEN_LED1, OUTPUT);
  pinMode(GREEN_LED2, OUTPUT);
  pinMode(GREEN_LED3, OUTPUT);
  
  pinMode(RED_LED1, OUTPUT);
  pinMode(RED_LED2, OUTPUT);
  pinMode(RED_LED3, OUTPUT);

  servoMotor.attach(SERVO_PIN);
  
  Serial.begin (9600);
}

long readDistance(int triggerPin, int echoPin) {
  
  pinMode(triggerPin, OUTPUT); 
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  pinMode(echoPin, INPUT);
  return pulseIn(echoPin, HIGH);
}

void handleLEDs(float distance, int greenLedPin, int redLedPin) {
  if (distance >= distanceThreshold){
    digitalWrite(greenLedPin, HIGH);
    digitalWrite(redLedPin, LOW);
    Serial.println("Empty slot!!");
  } else {
    digitalWrite(redLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
    Serial.println("Car is parked");
  }
}

void loop() {
  //... same code as above ...
  float d1 = 0.01723 * readDistance(t1, t1);
  float d2 = 0.01723 * readDistance(t2, t2);
  float d3 = 0.01723 * readDistance(t3, t3);
  
  Serial.println("d1 = " + String(d1) + "cm");
  Serial.println("d2 = " + String(d2) + "cm");
  Serial.println("d3 = " + String(d3) + "cm");
  
  if (digitalRead(IR_SENSOR_PIN) == LOW) { // Vehicle detected by IR sensor
    if (d1 > 100 || d2 > 100 || d3 > 100) {
      servoMotor.write(90); // Assuming 90 degrees opens the gate
      delay(500);
      servoMotor.write(0); // Assuming 0 degrees closes the gate after some time
      delay(500);
    } else {
      // Do nothing or maybe sound a buzzer to indicate parking full
    }
  }

  // Handle LEDs based on the distance readings
  handleLEDs(d1, GREEN_LED1, RED_LED1);
  handleLEDs(d2, GREEN_LED2, RED_LED2);
  handleLEDs(d3, GREEN_LED3, RED_LED3);
  
if (d1>100 & d2>100 & d3>100){
  lcd.setCursor(0,0);
  lcd.print("3 Slots Free");
  lcd.setCursor(0,1);
  lcd.print("Slot 1 2 3 Free");
  delay(500);
  }
else if((d1>100 & d2>100)|(d2>100 & d3>100)|(d3>100 & d1>100))
  {
  lcd.setCursor(0,0);
  lcd.print("2 Slots Free");
  lcd.setCursor(0,1);
    if(d1>100 & d2>100)
    lcd.print("Slot 1 & 2 Free");
    else if(d1>100 & d3>100)
    lcd.print("Slot 1 & 3 Free");
    else
    lcd.print("Slot 2 & 3 Free");
  delay(500);
  }
else if(d1<100 & d2<100 & d3<100)
  {
  lcd.setCursor(0,0);
  lcd.print("No Slot Free");
  lcd.setCursor(0,1);
  lcd.print("Parking Full");
  delay(500);
  }
else if((d1<100 & d2<100)|(d2<100 & d3<100)|(d3<100 & d1<100))
  {
  lcd.setCursor(0,0);
  lcd.print("1 Slot Free");
  lcd.setCursor(0,1);
    if(d1>100)
      lcd.print("Slot 1 is Free");
    else if (d2>100)
       lcd.print("Slot 2 is Free");
    else
       lcd.print("Slot 3 is Free");
  delay(500);
   }
  delay(100);
}