#include <Wire.h> 
#include <Adafruit_GFX.h> 
#include <Adafruit_SSD1306.h> 
#include <Keypad.h> 

#define TINGGI_LAYAR 64 // Tinggi layar OLED yang digunakan 
#define LEBAR_LAYAR 128 // Lebar layar OLED yang digunakan 
const byte ROWS = 4; // Jumlah baris keypad 
const byte COLS = 4; // Jumlah kolom keypad 

Adafruit_SSD1306 oled ( LEBAR_LAYAR, TINGGI_LAYAR, &Wire, -1 ); 

char Keys [ ROWS ] [ COLS ] = { // Membuat array keypad 
  ( '1' , '2' , '3' , 'A' ) , 
  ( '4' , '5' , '6' , 'B' ) , 
  ( '7' , '8' , '9' , 'C' ) , 
  ( '*' , '0' , '#' , 'D' ) };

byte rowPins [ ROWS ] = { 14 , 12 , 19 , 18 }; 
byte colPins [ COLS ] = { 5 , 4 , 2 , 15 };

Keypad customKeypad = Keypad ( makeKeymap ( Keys ) , rowPins , colPins , ROWS , COLS );   

char customKey; // Variabel penampung input keypad 
int number = 0; // Variabel penampung nilai angka 
int password = 1379; // Password 

void setup ( ) { 
  Serial.begin ( 9600 ); 
  // initialize OLED display with 12C address 0x3c 
  if ( !oled.begin ( SSD1306_SWITCHCAPVCC , 0x3C ) ) {
  Serial.println ( F ( "failed to start SSD1306 OLED" ) ); 
  while ( 1 ); 
  }
  oled.clearDisplay ( ); 
  
  oled.setTextSize ( 1 ); // Atur ukuran text 
  oled.setTextColor ( WHITE ); // Atur warna text 
  oled.setCursor ( 20 , 20 ); // Atur posisi text pada display 
  oled.println ( "SELAMAT DATANG" ); // Text yang dicetak 
  delay ( 2000 ); 
  oled.display ( ); 
  oled.clearDisplay(); // menampilkan display OLED
}

void loop() {
  oled.setTextSize ( 1 );  
  oled.setTextColor ( WHITE ); 
  oled.setCursor ( 0 , 0 ); 
  oled.print( "Input Password" ); // Tampilan pada layar 
  customKey = customKeypad.getKey ( ) ; // Baca input keypad

//-Prosedur jika input berupa angka-- 
  switch ( customKey ) {
  case '0' ... '9' : 
    oled.setTextSize ( 1 ); 
    oled.setTextColor ( WHITE ); 
    oled.setCursor ( 0,10 ); 
    number = number * 10 + ( customKey - '0' ); 
    oled.print ( number ); 
    oled.display ( ); 
    oled.clearDisplay ( ); 
  break; 
  
//-- Jika input ' # ' maka cek password --- 
  case ' # ' : 
    if(number == password) { // Jika password benar , maka 
    oled.setTextSize ( 1 ); 
    oled.setTextColor ( WHITE ); 
    oled.setCursor ( 0,10 ); 
    oled.print ( "Access Accepted" ) ; // Tampilan LCD 
    number = 0; 
    oled.display ( ); 
    oled.clearDisplay ( );
  }
    else { // Jika salah , maka
    oled.setTextSize( 1 ); 
    oled.setTextColor( WHITE ); 
    oled.setCursor ( 0,10 ); 
    oled.print ( " nvalid Password" ); // Tampilan LCD 
    oled.display ( ); 
    delay ( 2000 ); 
    number = 0; 
    oled.clearDisplay ( ); 
  break;
   
   // Jika input '*' maka hapus tampilan-- 
  case '*': 
    number = 0; 
    oled.clearDisplay ( ); 
  break;
  }
}}