#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // Address 0x27, 16 column and 2 rows

const int trigPin1 = 12; // Trigger pin of ultrasonic sensor 1
const int echoPin1 = 13; // Echo pin of ultrasonic sensor 1
const int trigPin2 = 14; // Trigger pin of ultrasonic sensor 2
const int echoPin2 = 15; // Echo pin of ultrasonic sensor 2

// Threshold distance for vacancy (in centimeters)
const float vacancyThreshold = 500.0;

// Function prototype
float measureDistance(int trigPin, int echoPin);

void setup() {
  Serial.begin(9600);
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  
  // Set ultrasonic sensor pins as input and output
  pinMode(trigPin1, OUTPUT);
  pinMode(echoPin1, INPUT);
  pinMode(trigPin2, OUTPUT);
  pinMode(echoPin2, INPUT);
}

void loop() {
  // Measure distance from ultrasonic sensor 1
  float distance1 = measureDistance(trigPin1, echoPin1);
  
  // Measure distance from ultrasonic sensor 2
  float distance2 = measureDistance(trigPin2, echoPin2);
  
  // Display status on LCD
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Space 1: ");
  if (distance1 < vacancyThreshold) {
    lcd.print("Vacant   ");
  } else {
    lcd.print("Occupied");
  }
  lcd.setCursor(0, 1);
  lcd.print("Space 2: ");
  if (distance2 > vacancyThreshold) {
    lcd.print("Vacant   ");
  } else {
    lcd.print("Occupied");
  }
  
  delay(1000); // Delay for readability
}

float measureDistance(int trigPin, int echoPin) {
  // Generate ultrasonic pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Measure echo time
  float duration = pulseIn(echoPin, HIGH);
  
  // Calculate distance in centimeters
  float distance = duration * 0.034 / 2;
  
  return distance;
}