#include <LiquidCrystal.h> 
#include <Keypad.h> 

#define redLED 11 
#define greenLED 12

const byte rows = 4; 
const byte cols = 4; 

char keyMap [rows] [cols] = { 
 {'1', '2', '3', 'A'},
 {'4', '5', '6', 'B'},
 {'7', '8', '9', 'C'},
 {'*', '0', '#', 'D'}
};

char password ='6'; 

byte rowPins [rows] = {1, 2, 3, 4}; 
byte colPins [cols] = {5, 6, 7, 8}; 

Keypad myKeypad = Keypad( makeKeymap(keyMap), rowPins, colPins, rows, cols);

LiquidCrystal lcd (A0, A1, A2, A3, A4, A5); 

void setup(){
 lcd.begin(16, 2);
 pinMode(redLED, OUTPUT); 
 pinMode(greenLED, OUTPUT);
 setLocked (true); 
}
void loop(){
 lcd.setCursor(0, 0);
 lcd.print(" Welcome");
 lcd.setCursor(0, 1);
 lcd.print(" Enter Password");
 char whichKey = myKeypad.waitForKey(); 
 if(whichKey == '*' || whichKey == '#' || whichKey == 'A' || whichKey == 'B' || whichKey == 'C' || whichKey == 'D')
 {
 setLocked (true);
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.print(" Invalid Key! ");
 delay(1000);
 lcd.clear();
 }
 if(whichKey == password )
 {
 setLocked (false);
 lcd.clear();
 lcd.setCursor(0, 0);
  lcd.print(" Accepted ");
 delay(1000);
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.clear();
 setLocked (true);
 }
 else
 {
 setLocked (true);
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.print(" Try again ");
 delay(1000);
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.clear();
 }
 delay(200);
}
void setLocked(int locked){
 if(locked){
 digitalWrite(redLED, HIGH);
 digitalWrite(greenLED, LOW);
 }
 else{
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, HIGH);
 }

}