4×4 Matrix Keypad

A 4×4 Matrix Keypad is a compact and versatile input device used in embedded systems, microcontroller projects, and security applications. It consists of 16 tactile keys arranged in a 4-row by 4-column grid, allowing efficient data entry with minimal wiring.

Key Features:

• Layout: 4 rows × 4 columns (16 keys)
• Interface: Matrix scanning using 8 GPIO pins
• Key Labels: Typically 0-9, A-D, *, and # (customizable)
• Operating Voltage: 3.3V – 5V (compatible with most MCUs)
• Material: Soft rubber or hard plastic with conductive backing
• Applications: Password entry, menu navigation, calculators, and robotics control

The 4×4 keypad is commonly used with Arduino, Raspberry Pi, STM32, and other microcontrollers, offering a simple yet reliable method for user input in various DIY and commercial applications.