Please note, I am using a 20x4 I2C LCD display in this sketch, please adjust to your display needs.
/* || @file Keypad Password || @version 1.0 || @author Andrew Mascolo || @date May 7, 2013 || || @description || Simple use of keypad, password and LCD */ #include <Keypad.h> #include <Wire.h> #include <LiquidCrystal_I2C.h> #define Password_Lenght 7 // Give enough room for six chars + NULL char LiquidCrystal_I2C lcd(0x20,20,4); char Data[Password_Lenght]; // 6 is the number of chars it can hold + the null char = 7 char Master[Password_Lenght] = "123456"; byte data_count = 0, master_count = 0; bool Pass_is_good; char customKey; const byte ROWS = 4; const byte COLS = 3; char keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'} }; byte rowPins[ROWS] = { 2,3,4,5}; //connect to the row pinouts of the keypad byte colPins[COLS] = { 10,9,8}; //connect to the column pinouts of the keypad Keypad customKeypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS); //initialize an instance of class NewKeypad void setup() { lcd.init();// initialize the lcd lcd.backlight(); } void loop() { lcd.setCursor(0,0); lcd.print("Enter Password"); customKey = customKeypad.getKey(); if (customKey) // makes sure a key is actually pressed, equal to (customKey != NO_KEY) { Data[data_count] = customKey; // store char into data array lcd.setCursor(data_count,1); // move cursor to show each new char lcd.print(Data[data_count]); // print char at said cursor data_count++; // increment data array by 1 to store new char, also keep track of the number of chars entered } if(data_count == Password_Lenght-1) // if the array index is equal to the number of expected chars, compare data to master { lcd.clear(); lcd.setCursor(0, 0); lcd.print("Password is "); if(!strcmp(Data, Master)) // equal to (strcmp(Data, Master) == 0) lcd.print("Good"); else lcd.print("Bad"); delay(1000);// added 1 second delay to make sure the password is completely shown on screen before it gets cleared. lcd.clear(); clearData(); } } void clearData() { while(data_count !=0) { // This can be used for any array size, Data[data_count--] = 0; //clear array for new data } return; }