#4.10.2.1. 예제 

#include <Keypad.h>

char keymap[3][3] = {

  {'1', '2', '3'},

  {'4', '5', '6'},

  {'7', '8', '9'}

};

byte rowPins[3] = {9, 8, 7};

byte colPins[3] = {5, 4, 3}; 

Keypad myKeypad = Keypad(makeKeymap(keymap), rowPins, colPins, 3, 3);

void setup() {

  Serial.begin(9600);

  pinMode(10, OUTPUT);

}

void loop() {

  char keypressed = myKeypad.getKey();

  if (keypressed != NO_KEY) {

    Serial.println(keypressed);

    if (keypressed == '1') {

      digitalWrite(10, HIGH);

    } else if (keypressed == '2') {

      digitalWrite(10, LOW);

    }

  }

}