#include "Keypad.h" const byte ROWS = 4; // number of rows const byte COLS = 3; // number of columns char keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'#','0','*'} }; byte rowPins[ROWS] = {8, 7, 6, 5}; // row pinouts of the keypad R1 = D8, R2 = D7, R3 = D6, R4 = D5 byte colPins[COLS] = {4, 3, 2}; // column pinouts of the keypad C1 = D4, C2 = D3, C3 = D2 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); }