#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);
}
void loop() {
char key = keypad.getKey();
if (key != NO_KEY) {
Serial.println(key);
}
}