#include <LiquidCrystal.h>

// LCD pin configuration
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

// Constants for the LDR
const float GAMMA = 0.7;
const float RL10 = 50;
const int ldrPin = A0; // Analog pin connected to AO of the LDR module
const int backlightPin = 6; // PWM pin for backlight control

void setup() {
  pinMode(backlightPin, OUTPUT);
  lcd.begin(16, 2); // Initialize the LCD
  lcd.print("Ambient Light:");
  Serial.begin(9600);
}

void loop() {
  int analogValue = analogRead(ldrPin);
  float voltage = analogValue / 1024.0 * 5.0;
  float resistance = 2000.0 * voltage / (1.0 - voltage / 5.0);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  int backlightBrightness = map(lux, 0, 1000, 255, 0); // Map lux to brightness (0-255)
  backlightBrightness = constrain(backlightBrightness, 0, 255);

  analogWrite(backlightPin, backlightBrightness); // Set backlight brightness

  lcd.setCursor(0, 1); // Set cursor to the second row
  lcd.print("Lux: ");
  lcd.print((int)lux); // Print the lux value

  delay(100);
}