YSEF Robotics

4x4 Matrix Keypad Module

The 4x4 Matrix Keypad is a simple input device used in robotics and embedded systems for number or command entry. It provides 16 keys (0–9, A–D, *, #) arranged in a matrix form to save microcontroller pins.

How It Works?

The keypad has 8 pins — 4 rows and 4 columns. When a key is pressed, a connection is made between a specific row and column, allowing the microcontroller to identify which key was pressed by scanning the matrix.

Key Features

16 Keys arranged in 4x4 matrix
Easy interfacing with Arduino and Raspberry Pi
Durable and compact membrane design
Requires only 8 digital I/O pins


// 4x4 Keypad Interfacing with Arduino

#include 

// Define number of rows and columns
const byte ROWS = 4;
const byte COLS = 4;

// Define the keymap matching your keypad layout
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

// Arduino pins connected to the keypad rows
byte rowPins[ROWS] = {9, 8, 7, 6};

// Arduino pins connected to the keypad columns
byte colPins[COLS] = {5, 4, 3, 2};

// Create the Keypad object
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  Serial.begin(9600);
  Serial.println("Keypad ready. Press any key...");
}

void loop() {
  char key = keypad.getKey();  // Get the key pressed (if any)
  if (key) {
    Serial.print("Key Pressed: ");
    Serial.println(key);
  }
}

Applications of 4x4 Keypad Module

Used widely for input in embedded, IoT, and robotics systems.

Password Locks

Used in electronic door locks or security systems.

Robot Control

Used for manual robot navigation and operation.

Menu Selection

For selecting options in embedded display menus.

DIY Calculators

Used as numeric input for mini calculators or IoT projects.

Keypad Module (4x4 Matrix)