4×4 Matrix Keypad — 16-Key Tactile Pushbutton, 8-Pin Header, Arduino Compatible

4×4 Matrix Keypad — 16-Key Tactile Pushbutton, 8-Pin Header, Arduino Compatible

This 4×4 matrix keypad provides 16 tactile pushbutton switches (S1–S16) arranged in a 4-row × 4-column matrix, allowing a microcontroller to scan all 16 keys using only 8 digital pins. It's the most efficient way to add a full keypad to an Arduino project — compatible with the popular Keypad.h library for zero-effort key detection. The buttons have a satisfying click and the PCB terminates in a standard 8-pin male header for easy wiring.

Module Specifications

• Keys: 16 tactile pushbutton switches (4 rows × 4 columns)
• Key Labels: S1–S16 (customizable in software)
• Interface: 8-pin male header (4 row pins + 4 column pins)
• Supply Voltage: 3.3V and 5V compatible (no power supply needed — passive matrix)
• PCB Dimensions: 43 × 39mm (1.7" × 1.54")

8-Pin Header Pinout (top to bottom)

• Col 3 | Col 2 | Col 1 | Col 0 | Row 0 | Row 1 | Row 2 | Row 3

How Matrix Scanning Works

The MCU drives one column LOW at a time while reading all 4 row pins. When a button is pressed, the row pin connected to that button goes LOW, identifying both the row and column — and therefore which key was pressed. This allows 16 keys to be scanned with only 8 MCU pins.

Arduino Wiring (Keypad.h Library)

• Row pins (R0–R3) → Arduino D2–D5
• Column pins (C0–C3) → Arduino D6–D9
• Install Keypad.h library from Arduino Library Manager
• Define key map, row pins, and column pins in sketch

Typical Applications

• Password entry: PIN code input for Arduino security systems and door locks
• Calculator: Numeric input for Arduino calculator projects
• Menu navigation: 16-key navigation for LCD menu systems
• Hex input: 0–9 and A–F input for embedded system configuration
• Game controller: 16-button input for Arduino-based games
• Industrial HMI: Compact keypad for embedded control panels

Package Contents

• 1 × 4×4 matrix keypad PCB with 16 tactile pushbutton switches and 8-pin male header

16 keys, 8 pins, zero effort — the 4×4 matrix keypad with Keypad.h library support is the fastest way to add full keypad input to any Arduino or microcontroller project.

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