#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4); // the I2C LCD address of your display might differ, in this case,
// replace this line: LiquidCrystal_I2C lcd(0x3F,20,4)
// with this:         LiquidCrystal_I2C lcd(I2C_adrs_of_your_display,20,4)
// to find it, first upload and run the I2C_scanner.txt code to your arduino - it will show you the I2C_adrs_of_your_display

// DECLARATION:
// Power for LCD
int LCD_power = 8;
int buzzerPin = 9; // You can use any digital pin
// beep/light
int signal_pin = 10;
int main_state = 0;
const int button_1 = 2;
boolean button_1_state = 0;
const int button_2 = 3;
boolean button_2_state = 0;
int timer = 1;
int timer_sec;
float timer_fast;
float timer_faster;
int timer_sec_remainder;
int timer_min;
int SEQ = 300;
// Bomb wires:
const int Red_wire = 12;
boolean R = 0;
const int Black_wire = 11;
boolean B = 0;
const int Green_wire = 7;
boolean G = 0;
const int Yellow_wire = 8;
boolean Y = 0;
int D_current[] = {R, B, G, Y};
// Disarm state:
int D_State = 0;
int D0[] = {0, 0, 0, 0};
int D1[] = {0, 0, 0, 0};
int D2[] = {0, 0, 0, 0};
int D3[] = {0, 0, 0, 0};
int readVcc() {
  // Read 1.1V reference against AVcc
  // set the reference to Vcc and the measurement to the internal 1.1V reference
#if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
  ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
  ADMUX = _BV(MUX5) | _BV(MUX0) ;
#else
  ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#endif

  delay(2); // Wait for Vref to settle
  ADCSRA |= _BV(ADSC); // Start conversion
  while (bit_is_set(ADCSRA, ADSC)); // measuring

  uint8_t low  = ADCL; // must read ADCL first - it then locks ADCH
  uint8_t high = ADCH; // unlocks both

  long result = (high << 8) | low;

  result = 1125300L / result; // Calculate Vcc (in mV); 1125300 = 1.1*1023*1000
  return result; // Vcc in millivolts
}


void setup() {
  pinMode(LCD_power, OUTPUT);
  digitalWrite(LCD_power, HIGH);
  // Signal pin:
  pinMode(signal_pin, OUTPUT);
  // Buttons:
  pinMode(button_1, INPUT);
  pinMode(button_2, INPUT);
  lcd.init();                      // initialize the lcd
  Serial.begin(9600);              // initialize debug serial
  // Bomb wires:
  pinMode(Red_wire, INPUT_PULLUP);
  pinMode(Black_wire, INPUT_PULLUP);
  pinMode(Green_wire, INPUT_PULLUP);
  pinMode(Yellow_wire, INPUT_PULLUP);
  // Initialize the buzzer pin as an OUTPUT
  pinMode(buzzerPin, OUTPUT);
  // INTRO MESSAGE TO LCD:

  digitalWrite(signal_pin, 1);
  delay(50);
  digitalWrite(signal_pin, 0);
  delay(50);
  digitalWrite(signal_pin, 1);
  delay(50);
  digitalWrite(signal_pin, 0);
  delay(50);

  lcd.backlight();
  lcd.clear();

  // INTRO:
  delay(500);
  lcd.setCursor(1, 0);
  lcd.print("Created");
  delay(500);
  lcd.setCursor(1, 0);
  lcd.print("Created by");
  delay(500);
  lcd.setCursor(1, 0);
  lcd.print("Created by Ben");
  delay(500);
  lcd.setCursor(0, 1);
  lcd.print("www.airsoft-onli");
  delay(1500);

  lcd.setCursor(0, 1);
  lcd.print(".airsoft-online-");
  delay(500);

  lcd.setCursor(0, 1);
  lcd.print("rsoft-online-jap");
  delay(500);

  lcd.setCursor(0, 1);
  lcd.print("ft-online-japan.");
  delay(500);

  lcd.setCursor(0, 1);
  lcd.print("online-japan.com");
  delay(2000);
  lcd.clear();

  readVcc();
  if (readVcc() >= 3800)
  {
    lcd.setCursor(0, 0);
    lcd.print("Voltage = ");
    lcd.print(readVcc() / 1000.00);
    lcd.print("v");
    lcd.setCursor(0, 1);
    lcd.print("Voltage Good!");
    delay(3000);
  }

  if (readVcc() <= 3800)
  {
    lcd.setCursor(0, 0);
    lcd.print("voltage =");
    lcd.print(readVcc() / 1000.00);
    lcd.print("v");
    lcd.setCursor(0, 1);
    lcd.print("Replace Battery!");
    delay(1000000);
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set timer [min]:");
  lcd.setCursor(0, 1);
  lcd.print("timer = ");
  lcd.print(timer);
}


void loop() {
  // STATE 0 - SET THE TIMER:
  if (main_state == 0) {
    button_1_state = digitalRead(button_1);
    if (button_1_state == LOW) {
      delay(100);
    }
    else if (button_1_state == HIGH) {
      timer = timer + 1;
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Set timer [min]:");
      lcd.setCursor(0, 1);
      lcd.print("timer = ");
      lcd.print(timer);
      delay(150);
    }
    button_2_state = digitalRead(button_2);
    if (button_2_state == LOW) {
      delay(1);
    }
    else if (button_2_state == HIGH) {
      //lcd.clear();
      //lcd.setCursor(0,0);
      //lcd.print("Timer set");
      //lcd.setCursor(0,1);
      //lcd.print("Timer[min] = ");
      //lcd.print(timer);
      main_state = 1;
      //delay(1000);
    }
  } // END STATE 0


  // STATE 1 - SET SNOOZE AND DISARM:
  else if (main_state == 1) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Generating");
    delay(500);
    lcd.setCursor(0, 0);
    lcd.print("Generating.");
    delay(500);
    lcd.setCursor(0, 0);
    lcd.print("Generating..");
    delay(500);
    lcd.setCursor(0, 0);
    lcd.print("Generating...");
    delay(500);
    lcd.setCursor(0, 1);
    lcd.print("Done!");
    delay(1000);

    // print a random number from 1 to 24, random(1, 25)
    randomSeed(analogRead(0));
    int SEQ = random(1, 25);
    // SETTING THE SEQ:
    if (SEQ == 1) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: R,B,G (01)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {1,0,0,0}; // *
      D1[0] = 1;
      //int D2[] = {1,1,0,0}; // **
      D2[0] = 1;
      D2[1] = 1;
      //int D3[] = {1,1,1,0}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[2] = 1;
      delay(2000);
    }
    else if (SEQ == 2) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: R,B,Y (02)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {1,0,0,0}; // *
      D1[0] = 1;
      //int D2[] = {1,1,0,0}; // **
      D2[0] = 1;
      D2[1] = 1;
      //int D3[] = {1,1,0,1}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 3) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: R,G,B (03)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {1,0,0,0}; // *
      D1[0] = 1;
      //int D2[] = {1,0,1,0}; // **
      D2[0] = 1;
      D2[2] = 1;
      //int D3[] = {1,1,1,0}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[2] = 1;
      delay(1000);
    }
    else if (SEQ == 4) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: R,G,Y (04)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {1,0,0,0}; // *
      D1[0] = 1;
      //int D2[] = {1,0,1,0}; // **
      D2[0] = 1;
      D2[2] = 1;
      //int D3[] = {1,0,1,1}; // Disarmed
      D3[0] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 5) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: R,Y,B (05)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {1,0,0,0}; // *
      D1[0] = 1;
      //int D2[] = {1,0,0,1}; // **
      D2[0] = 1;
      D2[3] = 1;
      //int D3[] = {1,1,0,1}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 6) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: R,Y,G (06)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {1,0,0,0}; // *
      D1[0] = 1;
      //int D2[] = {1,0,0,1}; // **
      D2[0] = 1;
      D2[3] = 1;
      //int D3[] = {1,0,1,1}; // Disarmed
      D3[0] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 7) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: B,R,G (07)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,1,0,0}; // *
      D1[1] = 1;
      //int D2[] = {1,1,0,0}; // **
      D2[0] = 1;
      D2[1] = 1;
      //int D3[] = {1,1,1,0}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[2] = 1;
      delay(1000);
    }
    else if (SEQ == 8) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: B,R,Y (08)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,1,0,0}; // *
      D1[1] = 1;
      //int D2[] = {1,1,0,0}; // **
      D2[0] = 1;
      D2[1] = 1;
      //int D3[] = {1,1,0,1}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 9) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: B,G,R (09)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,1,0,0}; // *
      D1[1] = 1;
      //int D2[] = {0,1,1,0}; // **
      D2[1] = 1;
      D2[2] = 1;
      //int D3[] = {1,1,1,0}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[2] = 1;
      delay(1000);
    }
    else if (SEQ == 10) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: B,G,Y (10)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,1,0,0}; // *
      D1[1] = 1;
      //int D2[] = {0,1,1,0}; // **
      D2[1] = 1;
      D2[2] = 1;
      //int D3[] = {0,1,1,1}; // Disarmed
      D3[1] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 11) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: B,Y,R (11)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,1,0,0}; // *
      D1[1] = 1;
      //int D2[] = {0,1,0,1}; // **
      D2[1] = 1;
      D2[3] = 1;
      //int D3[] = {1,1,0,1}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 12) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: B,Y,G (12)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,1,0,0}; // *
      D1[1] = 1;
      //int D2[] = {0,1,0,1}; // **
      D2[1] = 1;
      D2[3] = 1;
      //int D3[] = {0,1,1,1}; // Disarmed
      D3[1] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 13) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: G,R,B (13)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,1,0}; // *
      D1[2] = 1;
      //int D2[] = {1,0,1,0}; // **
      D2[0] = 1;
      D2[2] = 1;
      //int D3[] = {1,1,1,0}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[2] = 1;
      delay(1000);
    }
    else if (SEQ == 14) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: G,R,Y (14)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,1,0}; // *
      D1[2] = 1;
      //int D2[] = {1,0,1,0}; // **
      D2[0] = 1;
      D2[2] = 1;
      //int D3[] = {1,0,1,1}; // Disarmed
      D3[0] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 15) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: G,B,R (15)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,1,0}; // *
      D1[2] = 1;
      //int D2[] = {0,1,1,0}; // **
      D2[1] = 1;
      D2[2] = 1;
      //int D3[] = {1,1,1,0}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[2] = 1;
      delay(1000);
    }
    else if (SEQ == 16) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: G,B,Y (16)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,1,0}; // *
      D1[2] = 1;
      //int D2[] = {0,1,1,0}; // **
      D2[1] = 1;
      D2[2] = 1;
      //int D3[] = {0,1,1,1}; // Disarmed
      D3[1] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 17) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: G,Y,R (17)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,1,0}; // *
      D1[2] = 1;
      //int D2[] = {0,0,1,1}; // **
      D2[2] = 1;
      D2[3] = 1;
      //int D3[] = {1,0,1,1}; // Disarmed
      D3[0] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 18) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: G,Y,B (18)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,1,0}; // *
      D1[2] = 1;
      //int D2[] = {0,0,1,1}; // **
      D2[2] = 1;
      D2[3] = 1;
      //int D3[] = {0,1,1,1}; // Disarmed
      D3[1] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 19) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: Y,R,B (19)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,0,1}; // *
      D1[3] = 1;
      //int D2[] = {1,0,0,1}; // **
      D2[0] = 1;
      D2[3] = 1;
      //int D3[] = {1,1,0,1}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 20) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: Y,R,G (20)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,0,1}; // *
      D1[3] = 1;
      //int D2[] = {1,0,0,1}; // **
      D2[0] = 1;
      D2[3] = 1;
      //int D3[] = {1,0,1,1}; // Disarmed
      D3[0] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 21) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: Y,B,R (21)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,0,1}; // *
      D1[3] = 1;
      //int D2[] = {0,1,0,1}; // **
      D2[1] = 1;
      D2[3] = 1;
      //int D3[] = {1,1,0,1}; // Disarmed
      D3[0] = 1;
      D3[1] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 22) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: Y,B,G (22)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,0,1}; // *
      D1[3] = 1;
      //int D2[] = {0,1,0,1}; // **
      D2[1] = 1;
      D2[3] = 1;
      //int D3[] = {0,1,1,1}; // Disarmed
      D3[1] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 23) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: Y,G,R (23)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,0,1}; // *
      D1[3] = 1;
      //int D2[] = {0,0,1,1}; // **
      D2[2] = 1;
      D2[3] = 1;
      //int D3[] = {1,0,1,1}; // Disarmed
      D3[0] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    else if (SEQ == 24) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("KEY: Y,G,B (24)");
      // Set the Disarm steps {R,B,G,Y}:
      //int D0[] = {0,0,0,0}; // Fully armed
      //int D1[] = {0,0,0,1}; // *
      D1[3] = 1;
      //int D2[] = {0,0,1,1}; // **
      D2[2] = 1;
      D2[3] = 1;
      //int D3[] = {0,1,1,1}; // Disarmed
      D3[1] = 1;
      D3[2] = 1;
      D3[3] = 1;
      delay(1000);
    }
    // Move to next state:
    main_state = 2;
  } // END STATE 1



  // STATE 2 -:
  else if (main_state == 2) {
    // CONFIRM USER WROTE DOWN THE KEY:
    lcd.setCursor(0, 1);
    lcd.print("Press Red to ARM");
    button_2_state = digitalRead(button_2);
    if (button_2_state == LOW) {
      delay(100);
    }

    else if (button_2_state == HIGH) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("ARMED:");
      lcd.setCursor(7, 0);
      //lcd.print(timer_sec);
      timer_min = int(timer_sec / 60);
      timer_sec_remainder = timer_sec % 60;
      if (timer_min < 10) {
        lcd.print("0");
      }
      else {
        Serial.print(" ");
      }
      lcd.print(timer_min);
      if (timer_sec_remainder < 10) {
        lcd.print(":0");
      }
      else {
        lcd.print(":");
      }
      lcd.print(timer_sec_remainder);
      timer_sec = timer * 60;
      timer_fast = timer_sec / 6;
      timer_faster = timer_fast / 3;
      // Move to next state:
      main_state = 3;
    }

  }
  // END STATE 2



  // STATE 3 -:
  // - run timer
  else if (main_state == 3) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("ARMED:");
    lcd.setCursor(7, 0);
    //lcd.print(timer_sec);
    timer_min = int(timer_sec / 60);
    timer_sec_remainder = timer_sec % 60;
    if (timer_min < 10) {
      lcd.print("0");
    }
    else {
      Serial.print(" ");
    }
    lcd.print(timer_min);
    if (timer_sec_remainder < 10) {
      lcd.print(":0");
    }
    else {
      lcd.print(":");
    }
    lcd.print(timer_sec_remainder);
    if (D_State == 0) {
      lcd.setCursor(0, 1);
      lcd.print("***");
    }
    else if (D_State == 1) {
      lcd.setCursor(0, 1);
      lcd.print("**");
    }
    else if (D_State == 2) {
      lcd.setCursor(0, 1);
      lcd.print("*");
    }



    if (timer_sec <= 0) {
      main_state = 4;
    }
    else if (timer_sec < timer_faster) {
      digitalWrite(signal_pin, 1);
      delay(50);
      timer_sec = timer_sec - 1;
      digitalWrite(signal_pin, 0);
      delay(200);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(200);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(200);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(200);
    }
    else if (timer_sec < timer_fast) {
      digitalWrite(signal_pin, 1);
      delay(50);
      timer_sec = timer_sec - 1;
      digitalWrite(signal_pin, 0);
      delay(400);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(400);
    }
    else if (timer_sec > 1) {
      digitalWrite(signal_pin, 1);
      delay(50);
      timer_sec = timer_sec - 1;
      digitalWrite(signal_pin, 0);
      delay(950);
    }


    //- check D_current
    check_D_current();

    if (D_State == 0) {
      if (
        D_current[0] == D0[0] and
        D_current[1] == D0[1] and
        D_current[2] == D0[2] and
        D_current[3] == D0[3]
      ) {
        Serial.println(" ");
      }
      else {
        if (
          D_current[0] == D1[0] and
          D_current[1] == D1[1] and
          D_current[2] == D1[2] and
          D_current[3] == D1[3]
        ) {
          digitalWrite(signal_pin, 1);
          delay(1000);
          D_State = 1;
          digitalWrite(signal_pin, 0);
          delay(50);
          digitalWrite(signal_pin, 1);
          delay(50);
          digitalWrite(signal_pin, 0);
          delay(50);
          digitalWrite(signal_pin, 1);
          delay(50);
          digitalWrite(signal_pin, 0);
        }
        //----- if D_current != D1 -> BOOM
        else {
          digitalWrite(signal_pin, 1);
          main_state = 4;
          delay(1000);
          digitalWrite(signal_pin, 1);
        }
      }
    } // end D_State == 0



    if (D_State == 1) {
      if (
        D_current[0] == D1[0] and
        D_current[1] == D1[1] and
        D_current[2] == D1[2] and
        D_current[3] == D1[3]
      ) {
        Serial.println(" ");
      }
      else {
        Serial.println(D2[0]);
        Serial.println(D2[1]);
        Serial.println(D2[2]);
        Serial.println(D2[3]);
        Serial.println(" ");
        if (
          D_current[0] == D2[0] and
          D_current[1] == D2[1] and
          D_current[2] == D2[2] and
          D_current[3] == D2[3]
        ) {
          digitalWrite(signal_pin, 1);
          delay(1000);
          D_State = 2;
          digitalWrite(signal_pin, 0);
          delay(50);
          digitalWrite(signal_pin, 1);
          delay(50);
          digitalWrite(signal_pin, 0);
          delay(50);
          digitalWrite(signal_pin, 1);
          delay(50);
          digitalWrite(signal_pin, 0);
        }
        else {
          digitalWrite(signal_pin, 1);
          main_state = 4;
          delay(1000);
          digitalWrite(signal_pin, 1);
        }
      }
    } // end D_State == 1



    if (D_State == 2) {
      //--- if D_current == D0 : pass
      if (
        D_current[0] == D2[0] and
        D_current[1] == D2[1] and
        D_current[2] == D2[2] and
        D_current[3] == D2[3]
      ) {
        Serial.println(" ");
      }
      //--- else if D_current != D0:
      else {
        //----- else if D_current == D1 -> D_state = 1
        if (
          D_current[0] == D3[0] and
          D_current[1] == D3[1] and
          D_current[2] == D3[2] and
          D_current[3] == D3[3]
        ) {
          digitalWrite(signal_pin, 1);
          delay(1000);
          D_State = 3;
          digitalWrite(signal_pin, 0);
          delay(50);
          digitalWrite(signal_pin, 1);
          delay(50);
          digitalWrite(signal_pin, 0);
          delay(50);
          digitalWrite(signal_pin, 1);
          delay(50);
          digitalWrite(signal_pin, 0);
        }
        //----- if D_current != D1 -> BOOM
        else {
          digitalWrite(signal_pin, 1);
          main_state = 4;
          delay(1000);
          digitalWrite(signal_pin, 1);
        }
      }
    } // end D_State == 2



    if (D_State == 3) {
      lcd.clear();
      lcd.setCursor(0, 0);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(50);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(50);
      digitalWrite(signal_pin, 1);
      delay(50);
      digitalWrite(signal_pin, 0);
      delay(50);
      lcd.print("  BOMB DEFUSED");
      delay(1000000);
    } // end D_State == 3


  } // END STATE 3


  // STATE 4 - BOOM, TERRORISTS WIN:
  else if (main_state == 4) {
    lcd.clear();
    lcd.setCursor(0, 0);
    digitalWrite(signal_pin, 10);
    lcd.print("  BOMB EXPLODED");
    for (int i = 200; i > 0; i--)  // this is the ultra hi definition explosion sound xD
  {
    tone(buzzerPin, i);
    delay(20);
  }
  noTone(buzzerPin);
  delay(100000);


  } // END STATE 4

} // END LOOP

// Check current bomb wires config:
void check_D_current() {
  R = digitalRead(Red_wire);
  B = digitalRead(Black_wire);
  G = digitalRead(Green_wire);
  Y = digitalRead(Yellow_wire);
  // Print for debug:
  Serial.println("D_current:");
  D_current[0] = R;
  D_current[1] = B;
  D_current[2] = G;
  D_current[3] = Y;
  Serial.println(D_current[0]);
  Serial.println(D_current[1]);
  Serial.println(D_current[2]);
  Serial.println(D_current[3]);
  Serial.println(" ");
}


/* DISARM SEQUENCE REF:
  R,B,G 1
  R,B,Y 2
  R,G,B 3
  R,G,Y 4
  R,Y,B 5
  R,Y,G 6

  B,R,G 7
  B,R,Y 8
  B,G,R 9
  B,G,Y 10
  B,Y,R 11
  B,Y,G 12

  G,R,B 13
  G,R,Y 14
  G,B,R 15
  G,B,Y 16
  G,Y,R 17
  G,Y,B 18

  Y,R,B 19
  Y,R,G 20
  Y,B,R 21
  Y,B,G 22
  Y,G,R 23
  Y,G,B 24
*/