#include <Keypad.h>
String input_pass;
String pass = "2278";
String passBuz = "7777";
const uint8_t ROWS = 4;
const uint8_t COLS = 4;
char keys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[COLS] = { 5, 4, 3, 2 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; // Pins connected to R1, R2, R3, R4

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  Serial.begin(9600);
}

void loop() {
char key = keypad.getKey();

  if (key != NO_KEY) {
    if(key){
    if(key == '*')
    { 
      if ( input_pass == passBuz )
      {
        tone(12,700);
      }
if (input_pass == pass ){
  digitalWrite(13, HIGH );
}
    }
else if (key == 'D')
{
  input_pass = "";
}
else {
  input_pass += key;
}

    }
  
  Serial.println(input_pass );
}
}