#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};
uint8_t rowPins[ROWS] = {9,8,7,6};

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


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

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

  if (key!=NO_KEY)  {
    Serial.println(key);
  }

  // put your main code here, to run repeatedly:

}