#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'},

 { '5', '6', '7', '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);

}



void loop(){

 char key = keypad.getKey();



  if (key != NO_KEY) {

   Serial.println(key);

 }

}