#include <Keypad.h>

// Define the keypad layout (4x4 matrix)
const byte ROW_NUM = 4; // four rows
const byte COL_NUM = 4; // four columns

// Define the row and column pinouts
char keys[ROW_NUM][COL_NUM] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

byte pin_rows[ROW_NUM] = {0, 1, 2, 3}; // Connect to the row pinouts
byte pin_column[COL_NUM] = {4, 5, 8, 9}; // Connect to the column pinouts

// Create the keypad object
Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COL_NUM);

void setup() {
  Serial.begin(115200); // Start Serial Monitor at 115200 baud
  Serial.println("Enter a number:");
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    Serial.print("You pressed: ");
    Serial.println(key);
  }
}