Connecting a 4X4 Membrane Keypad to an Arduino

You can use any Arduino compatible board with 8 free digital pins

First install the Keypad Library

In the Arduino IDE go to:

Sketch->Include Library->Manage Libraries,then search for Keypad and install.

Open the example sketch and edit it.

Example–>Keypad–>HelloKeypad

#include <Keypad.h>

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char keys[ROWS][COLS] = {
{'1','2','3','A'},
{'4','5','6','B'},
{'7','8','9','C'},
{'*','0','#','D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad

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

void setup(){
Serial.begin(9600);
}

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

if (key){
Serial.println(key);
}
}

Connecting the Arduino to the Keypad

Testing

Upload the sketch to your Arduino and open the Serial Monitor. Press any key and see if it is displayed correctly in the serial monitor. If you get wrong key check the connection – rows and columns might be reversed on your keypad.