#include <Keypad.h>

// symbols on the keypad
char keys [4][4] = {
  {'1','2','3','A'},
  {'5','6','7','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

byte rowPins[4] = {11, 10, 9, 8}; // connect row pinouts of the keypad
byte columnPins[4] = {7, 6, 5, 4}; // connect column pinouts of the keypad

// initialize a class Keypad
Keypad myKeypad = Keypad(makeKeymap(keys), rowPins, columnPins, 4, 4);

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600); // baud rate of 9600
}

void loop() {
  // put your main code here, to run repeatedly:
  char keyPressed = myKeypad.getKey();
  // if there is character input, send it to serial port
  if(keyPressed){
    Serial.println(keyPressed);
  }
}