4x4 Matrix 16-Button Keypad Keyboard Module

Wiring sixteen individual buttons straight to a microcontroller would use up sixteen separate pins, but this keypad arranges its sixteen buttons into a 4x4 row-and-column matrix so a project can read every key using just eight pins and a short scanning routine that most Arduino keypad libraries already handle out of the box. The familiar 0-9, A-D, and asterisk/pound layout makes it a natural fit for security code locks, calculator-style projects, menu navigation on simple embedded devices, and any build that needs more input options than a couple of push buttons can offer. Its flat, low-profile design and adhesive backing option make it easy to mount flush onto the front of a project enclosure rather than leaving loose wiring exposed.