#include <Keypad.h>
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);
////
int buzzerPin = 10;
bool FMelody = false;
String KeyWord = "242424";
String buf = "";
long unsigned int Timer = 0;

void setup() {
  Serial.begin(9600);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  ChekInput();
  PrintMessage();
  GoMelody();
  
}

void GoMelody()
{
  if(FMelody == true)
  {
    tone(buzzerPin, 31);
    delay(1000);
    noTone(buzzerPin);
    delay(1000);
    tone(buzzerPin, 100, 1000);
    delay(2000);
    FMelody = false;
  }
}

void ChekInput()
{
  char key = keypad.getKey();
  if (key != NO_KEY){ 
    Timer = millis();
    buf += key;
    if (buf.equals(KeyWord)){
      FMelody = true;
      buf = "";
    }
  }
}
void PrintMessage()
{
  if (FMelody){
      Serial.println("It was entered keyword, launch the melody");
      Serial.println("Wait till melody has been played");
  }
  else if(!buf.equals(""))
    if(millis() - Timer >= 5000){
      Timer = millis();
      Serial.println("You print " + buf);
       buf = "";
      Serial.println("It was NOT entered keyword");
    }
}