#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <EEPROM.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);

// Sensor pins
#define SENSOR1_PIN 6       // DS18B20 sensor 1
#define SENSOR2_PIN 7       // DS18B20 sensor 2
#define SENSOR3_PIN 8       // DS18B20 sensor 3
#define SENSOR4_PIN 9       // DS18B20 sensor 4

// Output pins
#define RELAY1 10         // RELAY control pin
#define RELAY2 11         // RELAY control pin
#define RELAY3 12         // RELAY control pin
#define RELAY4 13         // RELAY control pin
#define BUZZER A4        // Buzzer control pin

// DS18B20 setup for 4 sensors
OneWire oneWire1(SENSOR1_PIN);
OneWire oneWire2(SENSOR2_PIN);
OneWire oneWire3(SENSOR3_PIN);
OneWire oneWire4(SENSOR4_PIN);

DallasTemperature sensor1(&oneWire1);
DallasTemperature sensor2(&oneWire2);
DallasTemperature sensor3(&oneWire3);
DallasTemperature sensor4(&oneWire4);

float temperature1 = 0;
float temperature2 = 0;
float temperature3 = 0;
float temperature4 = 0;

int level = 0;
int index1 = 0;
int index2 = 0;

int my_1st_digit = 0;
int my_2nd_digit = 0;
int my_3rd_digit = 0;
int my_4th_digit = 0;
int password_1st_digit = 1;
int password_2nd_digit = 2;
int password_3rd_digit = 3;
int password_4th_digit = 4;

int t1_mode = 1;
int t1_low_value = 0;
int t1_high_value = 0;
int t2_mode = 1;
int t2_low_value = 0;
int t2_high_value = 0;
int t3_mode = 1;
int t3_low_value = 0;
int t3_high_value = 0;
int t4_mode = 1;
int t4_low_value = 0;
int t4_high_value = 0;

int backlight_mode = 1;

int upButton = 4;
int downButton = 3;
int selectButton = 2;
int backButton = 5;


unsigned long start_time = 0;
unsigned long hold_time = 0;

unsigned long backlight_start_time = 0;
bool backlightOn = false;          // Track backlight state
int backlight_duration = 5000;

void welcome_screen() {
  lcd.setCursor(3, 0);
  lcd.print("--<WELCOME>--");
  lcd.setCursor(3, 1);
  lcd.print("Multifunction");
  lcd.setCursor(4, 2);
  lcd.print("Temperature");
  lcd.setCursor(5, 3);
  lcd.print("Controller");
}

void main_screen() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("T1: ");
  lcd.print(temperature1);
  lcd.print((char)223);
  lcd.print("C");
  lcd.print("  R1: ");
  lcd.print("OFF");
  lcd.setCursor(0, 1);
  lcd.print("T2: ");
  lcd.print(temperature2);
  lcd.print((char)223);
  lcd.print("C");
  lcd.print("  R2: ");
  lcd.print("OFF");
  lcd.setCursor(0, 2);
  lcd.print("T3: ");
  lcd.print(temperature3);
  lcd.print((char)223);
  lcd.print("C");
  lcd.print("  R3: ");
  lcd.print("OFF");
  lcd.setCursor(0, 3);
  lcd.print("T4: ");
  lcd.print(temperature4);
  lcd.print((char)223);
  lcd.print("C");
  lcd.print("  R4: ");
  lcd.print("OFF");
}

void about_device_screen() {
  lcd.clear();
  lcd.setCursor(3, 0);
  lcd.print("MultiFunction");
  lcd.setCursor(2, 1);
  lcd.print("Temp Controller");
  lcd.setCursor(1, 2);
  lcd.print("4 channel, 4 modes");
  lcd.setCursor(1, 3);
  lcd.print("4 DS18B20, 4 RELAY");
}
void about_developer_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("ABUL KASEM");
  lcd.setCursor(1, 1);
  lcd.print("Sub-Assistant Engr.");
  lcd.setCursor(3, 2);
  lcd.print("BPDB, Dinajpur");
  lcd.setCursor(0, 3);
  lcd.print("[email protected]");
}

void my_1st_digit_screen() {
  lcd.clear();
  lcd.setCursor(3, 0);
  lcd.print("Enter Password");
  lcd.setCursor(8, 2);
  lcd.print(my_1st_digit);
  lcd.print("*");
  lcd.print("*");
  lcd.print("*");
}
void my_2nd_digit_screen() {
  lcd.setCursor(3, 0);
  lcd.print("Enter Password");
  lcd.setCursor(8, 2);
  lcd.print("*");
  lcd.print(my_2nd_digit);
  lcd.print("*");
  lcd.print("*");
}
void my_3rd_digit_screen() {
  lcd.setCursor(3, 0);
  lcd.print("Enter Password");
  lcd.setCursor(8, 2);
  lcd.print("*");
  lcd.print("*");
  lcd.print(my_3rd_digit);
  lcd.print("*");
}
void my_4th_digit_screen() {
  lcd.setCursor(3, 0);
  lcd.print("Enter Password");
  lcd.setCursor(8, 2);
  lcd.print("*");
  lcd.print("*");
  lcd.print("*");
  lcd.print(my_4th_digit);
}

void menu_screen() {
  lcd.clear();
  lcd.setCursor(1, 0);
  lcd.print("Setting");
  lcd.setCursor(1, 1);
  lcd.print("About Device");
  lcd.setCursor(1, 2);
  lcd.print("About Developer");
  switch (index1) {
      case 0: lcd.setCursor(0, 0); lcd.print(">"); break;
      case 1: lcd.setCursor(0, 1); lcd.print(">"); break;
      case 2: lcd.setCursor(0, 2); lcd.print(">"); break;
    }
}
void setting_screen() {
  lcd.clear();
  lcd.setCursor(7, 0);
  lcd.print("Setting");
  if (index2 == 0 || index2 == 1 || index2 == 2){
   lcd.setCursor(1, 1);
   lcd.print("T1 Mode   : ");
   switch (t1_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
   lcd.setCursor(1, 2);
   lcd.print("T1 L.Value: ");
   lcd.print(t1_low_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   lcd.setCursor(1, 3);
   lcd.print("T1 H.Value: ");
   lcd.print(t1_high_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   switch (index2) {
      case 0: lcd.setCursor(0, 1); lcd.print(">"); break;
      case 1: lcd.setCursor(0, 2); lcd.print(">"); break;
      case 2: lcd.setCursor(0, 3); lcd.print(">"); break;
    }
  } 
  else if (index2 == 3 || index2 == 4 || index2 == 5){
   lcd.setCursor(1, 1);
   lcd.print("T2 Mode   : ");
   switch (t2_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
   lcd.setCursor(1, 2);
   lcd.print("T2 L.Value: ");
   lcd.print(t2_low_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   lcd.setCursor(1, 3);
   lcd.print("T2 H.Value: ");
   lcd.print(t2_high_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   switch (index2) {
      case 3: lcd.setCursor(0, 1); lcd.print(">"); break;
      case 4: lcd.setCursor(0, 2); lcd.print(">"); break;
      case 5: lcd.setCursor(0, 3); lcd.print(">"); break;
    }
  } 
  else if (index2 == 6 || index2 == 7 || index2 == 8){
   lcd.setCursor(1, 1);
   lcd.print("T3 Mode   : ");
   switch (t3_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
   lcd.setCursor(1, 2);
   lcd.print("T3 L.Value: ");
   lcd.print(t3_low_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   lcd.setCursor(1, 3);
   lcd.print("T3 H.Value: ");
   lcd.print(t3_high_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   switch (index2) {
      case 6: lcd.setCursor(0, 1); lcd.print(">"); break;
      case 7: lcd.setCursor(0, 2); lcd.print(">"); break;
      case 8: lcd.setCursor(0, 3); lcd.print(">"); break;
    }
  } 
  else if (index2 == 9 || index2 == 10 || index2 == 11){
   lcd.setCursor(1, 1);
   lcd.print("T4 Mode   : ");
   switch (t4_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
   lcd.setCursor(1, 2);
   lcd.print("T4 L.Value: ");
   lcd.print(t4_low_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   lcd.setCursor(1, 3);
   lcd.print("T4 H.Value: ");
   lcd.print(t4_high_value);
   lcd.print((char)223); // Degree symbol
   lcd.print("C");
   switch (index2) {
      case 9: lcd.setCursor(0, 1); lcd.print(">"); break;
      case 10: lcd.setCursor(0, 2); lcd.print(">"); break;
      case 11: lcd.setCursor(0, 3); lcd.print(">"); break;
    }
  } 
  else if (index2 == 12){
   lcd.setCursor(1, 1);
   lcd.print("Backlight : ");
   switch (backlight_mode) {
      case 1: lcd.print("Normal"); break;
      case 2: lcd.print("Always"); break;
    }
   switch (index2) {
      case 12: lcd.setCursor(0, 1); lcd.print(">"); break;
    }
  } 
}

void login_success_screen() {
  lcd.clear();
  lcd.setCursor(7, 1);
  lcd.print("Success");
}
void incorrect_password_screen() {
  lcd.clear();
  lcd.setCursor(1, 1);
  lcd.print("Incorrect Password");
}
//////////////////////////////////////////////
void t1_mode_screen() {
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("T1 Mode");
  lcd.setCursor(6, 2);
  lcd.print("<");
  switch (t1_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
  lcd.print(">");
}
void t1_low_value_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T1 L.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t1_low_value);
  lcd.print(">+");
}
void t1_high_value_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T1 H.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t1_high_value);
  lcd.print(">+");
}
///////////////////////////////////////////////
void t2_mode_screen() {
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("T2 Mode");
  lcd.setCursor(6, 2);
  lcd.print("<");
  switch (t2_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
  lcd.print(">");
}
void t2_lvalue_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T2 L.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t2_low_value);
  lcd.print(">+");
}
void t2_hvalue_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T2 H.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t2_high_value);
  lcd.print(">+");
}
///////////////////////////////////////
void t3_mode_screen() {
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("T3 Mode");
  lcd.setCursor(6, 2);
  lcd.print("<");
  switch (t3_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
  lcd.print(">");
}
void t3_lvalue_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T3 L.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t3_low_value);
  lcd.print(">+");
}
void t3_hvalue_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T3 H.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t3_high_value);
  lcd.print(">+");
}
//////////////////////////////////////
void t4_mode_screen() {
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("T4 Mode");
  lcd.setCursor(6, 2);
  lcd.print("<");
  switch (t4_mode) {
      case 1: lcd.print("Heater"); break;
      case 2: lcd.print("Cooler"); break;
      case 3: lcd.print("Over T"); break;
      case 4: lcd.print("Under T"); break;
    }
  lcd.print(">");
}
void t4_lvalue_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T4 L.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t4_low_value);
  lcd.print(">+");
}
void t4_hvalue_screen() {
  lcd.clear();
  lcd.setCursor(5, 0);
  lcd.print("T4 H.Value");
  lcd.setCursor(7, 2);
  lcd.print("-<");
  lcd.print(t4_high_value);
  lcd.print(">+");
}
/////////////
void saved_screen() {
  lcd.clear();
  lcd.setCursor(8, 1);
  lcd.print("Saved");
}
void backlight_screen() {
  lcd.clear();
  lcd.setCursor(6, 0);
  lcd.print("Backlight");
  lcd.setCursor(6, 2);
  lcd.print("<");
  switch (backlight_mode) {
      case 1: lcd.print("Normal"); break;
      case 2: lcd.print("Always"); break;
    }
  lcd.print(">");
}


//*********************************************************
void buttonPress() {
  if (!digitalRead(upButton)) {
    if (backlight_mode == 1) {
      lcd.backlight();               // Turn on the backlight
      backlightOn = true;
      backlight_start_time = millis(); 
    }
    if (level == 1) index1++;
    else if (level == 30) my_1st_digit++;
    else if (level == 31) my_2nd_digit++;
    else if (level == 32) my_3rd_digit++;
    else if (level == 33) my_4th_digit++;
    else if (level == 2) index2++;
    else if (level == 200) t1_mode++;
    else if (level == 201) t1_low_value++;
    else if (level == 202) t1_high_value++;
    else if (level == 203) t2_mode++;
    else if (level == 204) t2_low_value++;
    else if (level == 205) t2_high_value++;
    else if (level == 206) t3_mode++;
    else if (level == 207) t3_low_value++;
    else if (level == 208) t3_high_value++;
    else if (level == 209) t4_mode++;
    else if (level == 210) t4_low_value++;
    else if (level == 211) t4_high_value++;
    else if (level == 212) backlight_mode++;
    updateMenu();
    delay(100);
    start_time = millis();
    while (!digitalRead(upButton)){
      hold_time = millis() - start_time;
      if (hold_time > 1000) {
        if (level == 201) t1_low_value++;
        else if (level == 202) t1_high_value++;
        else if (level == 204) t2_low_value++;
        else if (level == 205) t2_high_value++;
        else if (level == 207) t3_low_value++;
        else if (level == 208) t3_high_value++;
        else if (level == 210) t4_low_value++;
        else if (level == 211) t4_high_value++;
        updateMenu();
        delay(100);
      }
    }
  }
  if (!digitalRead(downButton)) {
    if (backlight_mode == 1) {
      lcd.backlight();               // Turn on the backlight
      backlightOn = true;
      backlight_start_time = millis(); 
    }
    if (level == 1) index1--;
    else if (level == 30) my_1st_digit--;
    else if (level == 31) my_2nd_digit--;
    else if (level == 32) my_3rd_digit--;
    else if (level == 33) my_4th_digit--;
    else if (level == 2) index2--;
    else if (level == 200) t1_mode--;
    else if (level == 201) t1_low_value--;
    else if (level == 202) t1_high_value--;
    else if (level == 203) t2_mode--;
    else if (level == 204) t2_low_value--;
    else if (level == 205) t2_high_value--;
    else if (level == 206) t3_mode--;
    else if (level == 207) t3_low_value--;
    else if (level == 208) t3_high_value--;
    else if (level == 209) t4_mode--;
    else if (level == 210) t4_low_value--;
    else if (level == 211) t4_high_value--;
    else if (level == 212) backlight_mode--;
    updateMenu();
    delay(100);
    start_time = millis();
    while (!digitalRead(downButton)){
      hold_time = millis() - start_time;
      if (hold_time > 1000) {
        if (level == 201) t1_low_value--;
        else if (level == 202) t1_high_value--;
        else if (level == 204) t2_low_value--;
        else if (level == 205) t2_high_value--;
        else if (level == 207) t3_low_value--;
        else if (level == 208) t3_high_value--;
        else if (level == 210) t4_low_value--;
        else if (level == 211) t4_high_value--;
        updateMenu();
        delay(100);
      }
    }
  }
  if (!digitalRead(selectButton)) {
    if (backlight_mode == 1) {
      lcd.backlight();               // Turn on the backlight
      backlightOn = true;
      backlight_start_time = millis(); 
    }
    executeAction();
    updateMenu();
    delay(100);
    while (!digitalRead(selectButton));
  }
  if (!digitalRead(backButton)) {
    if (backlight_mode == 1) {
      lcd.backlight();               // Turn on the backlight
      backlightOn = true;
      backlight_start_time = millis(); 
    }
    if (level == 1) level = 0;
    else if (level == 30 || level == 31 || level == 32 || level == 33 || level == 4 || level == 5 || level == 2) level = 1;
    else if (level == 200 || level == 201 || level == 202 || level == 203 || level == 204 || level == 205 || level == 206 ||
             level == 207 || level == 208 || level == 209 || level == 210 || level == 211 || level == 212) level = 2;
    updateMenu();
    delay(100);
    while (!digitalRead(backButton));
  }
}

void reset_digit() {
  my_1st_digit = 0;
  my_2nd_digit = 0;
  my_3rd_digit = 0;
  my_4th_digit = 0;
}

//*************************************************************
void executeAction() {
  if (level == 0) {
    level = 1;
    index1 = 0;
  } 
  else if (level == 1) {
    switch (index1) {
      case 0: level = 30; break;
      case 1: level = 4; break;
      case 2: level = 5; break;
    }
  } 
  else if (level == 2) {
    switch (index2) {
      case 0: level = 200; break;
      case 1: level = 201; break;
      case 2: level = 202; break;
      case 3: level = 203; break;
      case 4: level = 204; break;
      case 5: level = 205; break;
      case 6: level = 206; break;
      case 7: level = 207; break;
      case 8: level = 208; break;
      case 9: level = 209; break;
      case 10: level = 210; break;
      case 11: level = 211; break;
      case 12: level = 212; break;
    }
  }
  else if (level == 30) {
    level = 31;
  } else if (level == 31) {
    level = 32;
  } else if (level == 32) {
    level = 33;
  } 
  else if (level == 33) {
    if (my_1st_digit == password_1st_digit && my_2nd_digit == password_2nd_digit && my_3rd_digit == password_3rd_digit && my_4th_digit == password_4th_digit) {
      login_success_screen();
      delay(1000);
      reset_digit();
      level = 2;
    } else {
      incorrect_password_screen();
      delay(1000);
      reset_digit();
      level = 1;
    }
  }
  else if (level == 200) {saved_screen(); delay(1000); level = 2;}
  else if (level == 201) {saved_screen(); delay(1000); level = 2;}
  else if (level == 202) {saved_screen(); delay(1000); level = 2;}
  else if (level == 203) {saved_screen(); delay(1000); level = 2;}
  else if (level == 204) {saved_screen(); delay(1000); level = 2;}
  else if (level == 205) {saved_screen(); delay(1000); level = 2;}
  else if (level == 206) {saved_screen(); delay(1000); level = 2;}
  else if (level == 207) {saved_screen(); delay(1000); level = 2;}
  else if (level == 208) {saved_screen(); delay(1000); level = 2;}
  else if (level == 209) {saved_screen(); delay(1000); level = 2;}
  else if (level == 210) {saved_screen(); delay(1000); level = 2;}
  else if (level == 211) {saved_screen(); delay(1000); level = 2;}
  else if (level == 212) {saved_screen(); delay(1000); level = 2;}
  
} 

//***********************************************************
void updateMenu() {
  if (level == 0) main_screen();
  else if (level == 1) {
    if (index1 < 0) index1 = 2;
    if (index1 > 2) index1 = 0;
    menu_screen();
  }
  else if (level == 4) {
    about_device_screen();
  }
  else if (level == 5) {
    about_developer_screen();
  }
  else if (level == 30) {
    if (my_1st_digit < 0) {
      my_1st_digit = 9;
    }
    if (my_1st_digit > 9) {
      my_1st_digit = 0;
    }
    my_1st_digit_screen();
  } else if (level == 31) {
    if (my_2nd_digit < 0) {
      my_2nd_digit = 9;
    }
    if (my_2nd_digit > 9) {
      my_2nd_digit = 0;
    }
    my_2nd_digit_screen();
  } else if (level == 32) {
    if (my_3rd_digit < 0) {
      my_3rd_digit = 9;
    }
    if (my_3rd_digit > 9) {
      my_3rd_digit = 0;
    }
    my_3rd_digit_screen();
  } else if (level == 33) {
    if (my_4th_digit < 0) {
      my_4th_digit = 9;
    }
    if (my_4th_digit > 9) {
      my_4th_digit = 0;
    }
    my_4th_digit_screen();
  }
  else if (level == 2) {
    if (index2 < 0) index2 = 12;
    if (index2 > 12) index2 = 0;
    setting_screen();
  }
  else if (level == 200) {
    if (t1_mode < 1) {
      t1_mode = 4;
    }
    if (t1_mode > 4) {
      t1_mode = 1;
    }
    t1_mode_screen();
  }
    else if (level == 201) {
    if (t1_low_value < 0) {
      t1_low_value = 99;
    }
    if (t1_low_value > 99) {
      t1_low_value = 0;
    }
    t1_low_value_screen();
  }
  else if (level == 202) {
    if (t1_high_value < 0) {
      t1_high_value = 99;
    }
    if (t1_high_value > 99) {
      t1_high_value = 0;
    }
    t1_high_value_screen();
  }
  else if (level == 203) {
    if (t2_mode < 1) {
      t2_mode = 4;
    }
    if (t2_mode > 4) {
      t2_mode = 1;
    }
    t2_mode_screen();
  }
    else if (level == 204) {
    if (t2_low_value < 0) {
      t2_low_value = 99;
    }
    if (t2_low_value > 99) {
      t2_low_value = 0;
    }
    t2_lvalue_screen();
  }
  else if (level == 205) {
    if (t2_high_value < 0) {
      t2_high_value = 99;
    }
    if (t2_high_value > 99) {
      t2_high_value = 0;
    }
    t2_hvalue_screen();
  }
  else if (level == 206) {
    if (t3_mode < 1) {
      t3_mode = 4;
    }
    if (t3_mode > 4) {
      t3_mode = 1;
    }
    t3_mode_screen();
  }
    else if (level == 207) {
    if (t3_low_value < 0) {
      t3_low_value = 99;
    }
    if (t3_low_value > 99) {
      t3_low_value = 0;
    }
    t3_lvalue_screen();
  }
  else if (level == 208) {
    if (t3_high_value < 0) {
      t3_high_value = 99;
    }
    if (t3_high_value > 99) {
      t3_high_value = 0;
    }
    t3_hvalue_screen();
  }
  else if (level == 209) {
    if (t4_mode < 1) {
      t4_mode = 4;
    }
    if (t4_mode > 4) {
      t4_mode = 1;
    }
    t4_mode_screen();
  }
    else if (level == 210) {
    if (t4_low_value < 0) {
      t4_low_value = 99;
    }
    if (t4_low_value > 99) {
      t4_low_value = 0;
    }
    t4_lvalue_screen();
  }
  else if (level == 211) {
    if (t4_high_value < 0) {
      t4_high_value = 99;
    }
    if (t4_high_value > 99) {
      t4_high_value = 0;
    }
    t4_hvalue_screen();
  }
  else if (level == 212) {
    if (backlight_mode < 1) {
      backlight_mode = 2;
    }
    if (backlight_mode > 2) {
      backlight_mode = 1;
    }
    backlight_screen();
  }
}

void backlightMode() {
  // Turn off the backlight if the hold time has passed
  if (backlightOn && (millis() - backlight_start_time >= backlight_duration)) {
    lcd.noBacklight();              // Turn off the backlight
    backlightOn = false;
  }
  if (backlight_mode == 2) {
      lcd.backlight();               // Turn on the backlight
    }
}





//******************************************************
void setup() {
  lcd.init();
  lcd.noBacklight();
  pinMode(upButton, INPUT_PULLUP);
  pinMode(downButton, INPUT_PULLUP);
  pinMode(selectButton, INPUT_PULLUP);
  pinMode(backButton, INPUT_PULLUP);
  pinMode(RELAY1, OUTPUT);
  pinMode(RELAY2, OUTPUT);
  pinMode(RELAY3, OUTPUT);
  pinMode(RELAY4, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  digitalWrite(RELAY1, LOW);
  digitalWrite(RELAY2, LOW);
  digitalWrite(RELAY3, LOW);
  digitalWrite(RELAY4, LOW);
  digitalWrite(BUZZER, LOW);
  // Initialize DS18B20 sensors
  sensor1.begin();
  sensor2.begin();
  sensor3.begin();
  sensor4.begin();
  lcd.backlight();
  welcome_screen();
  delay(3000);
  updateMenu();
  delay(2000);
  lcd.noBacklight();
}

void loop() {
  backlightMode();
  buttonPress();

  // Request temperature data from all sensors
  sensor1.requestTemperatures();
  sensor2.requestTemperatures();
  sensor3.requestTemperatures();
  sensor4.requestTemperatures();

  // Read temperatures in Celsius
  float temperature1 = sensor1.getTempCByIndex(0);
  float temperature2 = sensor2.getTempCByIndex(0);
  float temperature3 = sensor3.getTempCByIndex(0);
  float temperature4 = sensor4.getTempCByIndex(0);

  // Handle sensor 1
  if (temperature1 != DEVICE_DISCONNECTED_C) {
    // Relay and buzzer control for different modes
    switch (t1_mode) {
      case 1:
        // Relay ON when below lower threshold, OFF when above upper threshold
        if (temperature1 <= t1_low_value) {
          digitalWrite(RELAY1, HIGH); // Turn relay ON
        } else if (temperature1 >= t1_high_value) {
          digitalWrite(RELAY1, LOW);  // Turn relay OFF
        }
        break;
      case 2:
        // Reverse logic: Relay OFF below lower threshold, ON above upper threshold
        if (temperature1 <= t1_low_value) {
          digitalWrite(RELAY1, LOW); // Turn relay OFF
        } else if (temperature1 >= t1_high_value) {
          digitalWrite(RELAY1, HIGH);  // Turn relay ON
        }
        break;
      case 3:
        // Activate buzzer above lower threshold, relay ON above upper threshold
        if (temperature1 >= t1_low_value) {
          digitalWrite(BUZZER, HIGH); // Turn buzzer ON
        }
        else {
          digitalWrite(BUZZER, LOW); // Turn buzzer ON
        }
        if (temperature1 >= t1_high_value) {
          digitalWrite(RELAY1, HIGH); // Turn relay ON
        }
        break;
      case 4:
        // Activate buzzer below lower threshold, relay ON below upper threshold
        if (temperature1 <= t1_low_value) {
          digitalWrite(RELAY1, HIGH); // Turn relay ON
        }
        
        if (temperature1 <= t1_high_value) {
          digitalWrite(BUZZER, HIGH); // Turn buzzer ON
        }
        else {
          digitalWrite(BUZZER, LOW); // Turn buzzer ON
        }
        break;
      default:
        Serial.println("Invalid mode!");
    }
  } else {
    Serial.println("Sensor 1 not found!");
  }


}