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

# define BETA 3950.0
# define DELAY_TIME 100
# define STARTING "  starting ...  "
# define WATERING "    watering    "

# define NUMBER_BYTE_CODE 0
# define NUMBER_BYTE {B11100, B10100, B11100, B00000, B00000, B00000, B00000, B00000}

# define TEMP_SENSOR_IN A0

# define TIME_LINE 0
# define TEMPERATURE_LINE 1

LiquidCrystal_I2C lcd (0x27, 16, 2);

float current_temp = 0.0;
unsigned short write_lcd = 1;

//const char *ALL_MENU[] = {};

void setup()
{
  byte special_char[] = NUMBER_BYTE;
  
  lcd.init();
  lcd.createChar(NUMBER_BYTE_CODE, special_char);
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.display();
  lcd.clear();
  lcd.print(STARTING);
  Serial.begin(9600);
}

void loop()
{
  read_temperature_v2();
  display_temperature();
  delay(DELAY_TIME); 
}

void read_temperature(){
 
  int reading = analogRead(TEMP_SENSOR_IN);
  float tmp = ( ( (reading * 5) / 1024.0) - 0.5) * 100;
  
  if (tmp != current_temp){
    current_temp = tmp;
    write_lcd = 1;
  }
}

void read_temperature_v2(){

  int reading = analogRead(TEMP_SENSOR_IN);
  float tmp = 1 / (log(1 / (1023. / reading - 1)) / BETA + 1.0 / 298.15) - 273.15;
  
   if (tmp != current_temp){
    current_temp = tmp;
    write_lcd = 1;
  }
}

void display_temperature(){
  
  if (!write_lcd) return;
  
  lcd.clear();
  
  char float_str[4];
  dtostrf(current_temp, 2, 1,float_str);
    
  lcd.setCursor(5, TEMPERATURE_LINE);
  lcd.print(float_str);
  lcd.write(NUMBER_BYTE_CODE);
  lcd.print("C");
  
  write_lcd = 0;
}