#include <LCD-I2C.h> // Include LCD I2C library

LCD_I2C lcd(0x27, 16, 2); // Set up LCD (address, columns, rows)

#define pinTrig 2 // Ultrasonic sensor trigger pin
#define pinEcho 4 // Ultrasonic sensor echo pin
#define pinLed 5  // LED pin

// Function to measure distance from ultrasonic sensor
float getDistance(int trig, int echo) {
  pinMode(trig, OUTPUT);
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  
  pinMode(echo, INPUT);
  float distance = pulseIn(echo, HIGH) / 58.0; // Convert pulse time to cm

  // Handle possible error with pulseIn returning 0
  if (distance == 0) {
    return -1;  // Return -1 to indicate error
  } else {
    return distance;
  }
}

void setup() {
  Serial.begin(115200); // Activate serial monitor
  
  // Initialize LCD display
  lcd.init();
  lcd.display(); 
  lcd.backlight(); 
  
  // Initialize sensor and LED pins
  pinMode(pinTrig, OUTPUT);
  pinMode(pinEcho, INPUT);
  pinMode(pinLed, OUTPUT);
}

void loop() {
  lcd.clear(); // Clear the screen
  lcd.setCursor(5, 0); // Set position column 5, row 0
  lcd.print("Akhdan"); // Print on LCD
  lcd.setCursor(7, 1); // Set position column 7, row 1
  lcd.print("8K"); // Print on LCD
  delay(1000);
  
  lcd.clear(); // Clear the screen
  lcd.setCursor(1, 0); // Set position column 1, row 0
  lcd.print("Aku Belajar"); // Print on LCD
  lcd.setCursor(8, 1); // Set position column 8, row 1
  lcd.print("Robotika"); // Print on LCD
  delay(1000);

  // Read distance from the ultrasonic sensor
  float jarak = getDistance(pinTrig, pinEcho);

  // Check if the distance reading is valid
  if (jarak != -1) {
    // Display the distance on the LCD
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print("Jarak (cm) = ");
    lcd.setCursor(1, 1);
    lcd.print(jarak);
    
    // Check if the object is within 200 cm
    if (jarak <= 200) {
      digitalWrite(pinLed, HIGH); // Turn on the LED
      lcd.clear();
      lcd.print("Object Detected!");
    } else {
      digitalWrite(pinLed, LOW); // Turn off the LED
      lcd.clear();
      lcd.print("No Object");
    }
  } else {
    lcd.clear();
    lcd.print("Sensor Error");
  }

  delay(1000); // Small delay for readability
}