/* THIS PROGRAM IS DESIGNED TO OPEN CURTAINS IF THE BRGHTNESS IS ABOVE 
100 LUX AND CLOSE CURTAINS IF THE BRIGHTNESS IS BELOW 100 LUX. */

// Importing stepper motor and LCD libraries
#include <Stepper.h> 
#include <LiquidCrystal.h>

#define STEPS_PER_REVOLUTION 200

// Pins connected to stepper motor
#define STEPPER_PIN_1 5 
#define STEPPER_PIN_2 4
#define STEPPER_PIN_3 3
#define STEPPER_PIN_4 2

// Pin connected to light sensor
#define LIGHT_SENSOR_PIN A0 

// Threshold value for light level (set to 511 i.e 100 lux)
#define LIGHT_THRESHOLD 511 

//Initialize Stepper module
Stepper stepper(STEPS_PER_REVOLUTION, STEPPER_PIN_1, STEPPER_PIN_2, STEPPER_PIN_3, STEPPER_PIN_4);

//Initialize LCD module
LiquidCrystal lcd(8, 9, 10, 11, 12, 13); 

bool curtainsClosed = false;
const float GAMMA = 0.7;
const float RL10 = 50;

void setup() {
  stepper.setSpeed(30);
  lcd.begin(16, 2);
  lcd.print("Curtains");
}

void loop() {
  curtains();
}

// Function to compare light level with threshold
void curtains() {
  // Convert the analog value from LDR into lux value:
  int lightLevel = analogRead(LIGHT_SENSOR_PIN);
  float voltage = lightLevel / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
  lcd.clear();
  //Display brightness on LCD 
  lcd.setCursor(0,1);
  lcd.print("Brightness:");
  lcd.print(int(lux));
  
  if (lightLevel <= LIGHT_THRESHOLD && !curtainsClosed) {
    lcd.clear();
    closeCurtains();
  } 
  else if (lightLevel > LIGHT_THRESHOLD && curtainsClosed) {
    lcd.clear();
    openCurtains();
  }
  delay(100); //Time taken to check again
}

// Function to open curtains
void openCurtains() {
  lcd.print("Curtains Closed");
  stepper.step(-200);
  curtainsClosed=false;
}

// Function to close curtains
void closeCurtains() {
  lcd.print("Curtains Opened");
  stepper.step(200);
  curtainsClosed=true;
}