/*
wihokมาตรฐานวิชาชีพ62
*/
#include <LiquidCrystal_I2C.h>
#include <Servo.h>
Servo myservo;  // create servo object to control a servo
int potpin = 1;  // analog pin used to connect the potentiometer
int val;    // variable to read the value from the analog pin

#define LDR_PIN 2

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
  pinMode(LDR_PIN, INPUT);
  pinMode(13, OUTPUT);

  lcd.init();
  lcd.backlight();
}
void loop() {
  int analogValue = analogRead(A0);
  float voltage = analogValue / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  lcd.setCursor(2, 0);
  lcd.print("Room: ");
  if (lux > 50) {
    lcd.print("Light!");
  } else {
    lcd.print("Dark  ");
  }

  lcd.setCursor(0, 1);
  lcd.print("Light:");
  lcd.print(lux);
  lcd.print(" lux");
  if(lux < 300){
    digitalWrite(13, HIGH);
  }
  else{

    digitalWrite(13, LOW);
  }  
    val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023)
    val = map(val, 0, 1023, 0, 180);     // scale it to use it with the servo (value between 0 and 180)
    myservo.write(val);                  // sets the servo position according to the scaled value
    delay(15);                           // waits for the servo to get there
    
  delay(20);
}