4x3 Matrix Membrane Keypad (12 Button)

Product Overview

The 4x3 Matrix Membrane Keypad is a compact, ultra-thin numeric input interface designed for microcontroller projects requiring secure code entry or menu selection. Featuring 12 tactile buttons arranged in a standard 3-column by 4-row telephone grid layout, this keypad provides key inputs for numeric digits 0 through 9, as well as the asterisk and pound symbols. The flexible membrane structure includes a convenient peel-and-stick self-adhesive backing, allowing simple mounting onto enclosures, boxes, or flat control surfaces.

Technical Specifications and Connections

This membrane keypad communicates via a matrix scanning layout, reducing required microcontroller I/O pins down to just 7 connections (4 row lines and 3 column lines). It terminates in an 85mm flexible ribbon cable attached to a 7-pin standard 0.1 inch (2.54mm) pitch female header, making it directly compatible with breadboards, DuPont jumper wires, and standard header pins. Keypad physical body dimensions are 77mm in length by 70mm in width with an ultra-thin profile of 1mm, weighing approximately 7.5 grams.

Pinout Configuration

When facing the front of the keypad, the 7 connector pins from left to right correspond to Pin 1 (Row 1), Pin 2 (Row 2), Pin 3 (Row 3), Pin 4 (Row 4), Pin 5 (Column 1), Pin 6 (Column 2), and Pin 7 (Column 3). By setting row pins as outputs and column pins as inputs with internal pull-ups, microcontrollers can easily scan key presses using standard Arduino Keypad software libraries.

Applications

Common applications include electronic door locks, security passcode entry panels, DIY alarm systems, menu navigation controls for embedded devices, vending machine prototypes, and automated robotics control interfaces.