Logical Password Sequence

// Program written by Dan Hostler, August 2020.
// Feel free to use as you need to.
// PayPal donations appreciated at danhostler1985@yahoo.com




// LIBRARIES. (PLEASE INSTALL THESE LIBRARIES IF YOU HAVE NOT YET)
#include <Wire.h>               // deals with I2C connections
#include <LiquidCrystal_I2C.h>  // activates the LCD I2C library
#include <Keypad.h>             // activates the Keypad library




// VARIABLES FOR THE 8-NUMBER PASSWORD INPUT DATA
#define Password_Length 9                    // Amount of digits plus one null character (8 + 1 = 9) defines password length
char userInput[Password_Length];             // This variable will store the user input in a string
char Master[Password_Length] = "12345678";   // This variable holds the correct password that the user string must match, change as needed
char customKey;                              // This variable holds key input of every key pressed
byte pressCount = 0;                         // This variable holds a counter for the amount of times the keys were pressed




// KEYPAD CONFIGURATION (PLEASE MODIFY THIS SECTION IF YOUR KEYPAD WIRING IS DIFFERENT FROM BELOW)
const byte ROWS = 4; // Constants for row and 
const byte COLS = 3; // column size of your keypad.

char twelveKeys[ROWS][COLS] =                     // Physical layout of the keypad being used in this program
{ 
    {'1', '2', '3'}, 
    {'4', '5', '6'},
    {'7', '8', '9'},
    {'C', '0', 'E'} // C = CLEAR, E = ENTER
};

byte rowPins[ROWS] = {9, 8, 7, 6};  // Defines how rowPins are connected on the Arduino to the keypad: 9 = R1, 8 = R2, 7 = R3, 6 = R4
byte colPins[COLS] = {5, 4, 3};     // Defines how colPins are connected on the Arduino to the keypad: 5 = C1, 4 = C2, 3 = C3, 2 = C2 (if you have a 4x4 keypad) 




// OBJECT CONFIGURATIONS
Keypad customKeypad = Keypad(makeKeymap(twelveKeys), rowPins, colPins, ROWS, COLS); // Creates keypad "object"
LiquidCrystal_I2C lcd(0x27, 16, 2);                                                 // Creates LCD "object" (I2C address, rows, columns)




// PROGRAM SETUP
void setup() {

  // LCD Initialization
  lcd.backlight(); 
  lcd.init();
  lcd.clear();

}




// MAIN PROGRAM LOOP
void loop() {

  lcd.setCursor(0,0);
  lcd.print(" Type Password:");                                       // One space is offset to center the text on the LCD
  customKey = customKeypad.waitForKey();                              // Program will halt here until a key is pushed

  if (customKey != NO_KEY && customKey != 'C' && customKey != 'E')    // If the user presses the number keys, the data is entered
  {
  userInput[pressCount] = customKey;                                  // Password string is being collected by the userInput variable
  lcd.setCursor(pressCount + 4, 1);                                   // Four is added to pressCount to center the input on the LCD
  lcd.print("*");                                                     // Asterisks are printed for confidentiality 
  pressCount++;                                                       // Key press count will roll over until 8 digits are entered
  }

  else if (customKey == 'C')    // C is to clear the entire password input from any point and start over again as
  {                             // it calls up the clearData function.
  lcd.clear();
  clearData(); 
  }

  else if (customKey == 'E')    // If less than 8 digits are entered, the input will be invalid and 
  {                             // an error message will flash, then call the clearData function to
  lcd.clear();                  // start the entering process all over again.
  lcd.setCursor(0,0);
  lcd.print("INVALID ENTRY");
  delay(800);
  clearData();
  }

   
  if (pressCount == 8)         // Once 8 digits are entered, the function to check the password string is called up and
  {                            // both the character and string data are sent to the function.
  lcd.clear();
  waitHere();                  
  }

}


// THIS FUNCTION CHECKS THE PASSWORD STRING
void waitHere(){

  lcd.setCursor(0,0);
  lcd.print(" Type Password:"); 
  lcd.setCursor(0,1);
  lcd.print("    ********");                    // Password data is hidden as asterisks for confidentiality purposes and
                                                // is offset by 4 spaces to center the input on the LCD
                                                 
  customKey = customKeypad.waitForKey();        // Program will halt here until a key is pushed
  
  if (customKey != NO_KEY && customKey == 'E')  // The ENTER button is pushed and the password goes through the routine.
  {
  lcd.clear();
  lcd.setCursor(0,0);
    if (!strcmp(userInput, Master))             // The user input string is matched up with the Master password string and matches up
    {                                           // running the routine to grant access before returning back to the beginning.
    lcd.setCursor(0,0);
    lcd.print("ACCESS GRANTED.");
    lcd.setCursor(0,1);
    lcd.print("WELCOME!!");
    delay(5000);
    clearData(); 
    }
    else if (strcmp(userInput, Master))         // The user input string is matched up with the Master password string and does not match up
    {                                           // running the routine to deny access before returning back to the beginning.
    lcd.setCursor(0,0);
    lcd.print("ACCESS DENIED.");
    delay(2000);
    clearData(); 
    }
  }

  if (customKey != NO_KEY && customKey == 'C')  // If the CLEAR button is pushed, the data is cleared and the program starts over.
  {
  lcd.clear();
  clearData(); 
  }
  
  if (customKey != NO_KEY && customKey == '0')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '1')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '2')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '3')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '4')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '5')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '6')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '7')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '8')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }

  if (customKey != NO_KEY && customKey == '9')  // This numberical button has no purpose and does nothing when pressed.
  {
  waitHere();
  }
  
}




// OPTIONAL FUNCTIONS TO USE IN CASE YOU WISH TO EXPAND OUT YOUR PROGRAM
//void accessGranted(){
//  
//}
//
//void accessDenied(){
//  
//}




// CLEARS THE ARRAY DATA, STARTS PROGRAM ALL OVER AGAIN
void clearData() {  
  while (pressCount != 0) 
  {
  userInput[pressCount--] = 0;    // Clears out the user input data, both digit and string data are reset to zero.
  }
  setup();                        // Returns program back to the beginning
}