Adafruit Membrane 3x4 Matrix Keypad 12-button 7-pin .1" pitch 70x77mm adhesive

12-button membrane keypad for microcontroller

This 3x4 matrix keypad provides twelve tactile keys in a telephone-style layout. The thin, flexible membrane measures 70mm by 77mm and only 1mm thick, with an adhesive backing that sticks to most surfaces. It connects through a 7-pin 0.1" pitch header, requiring just seven microcontroller pins to scan the full grid. A 7-pin extra-long header strip is included for breadboard prototyping.

Low-profile design with minimal electrical load

The membrane construction adds only 7.5 grams and 1mm of height, so it fits inside tight enclosures without affecting airflow or adding thermal mass. Scanning the matrix draws negligible current from the microcontroller, leaving the power budget untouched for other peripherals. No active cooling or additional power circuitry is required, and the passive design produces zero acoustic noise during operation.

Adhesive backing and breadboard header simplify

The pre-applied adhesive lets you mount the keypad directly on a panel, enclosure wall, or handheld device after removing the protective paper. The included 7-pin extra-long header strip plugs straight into a standard 0.1" breadboard, giving 85mm of cable reach for comfortable wiring. No soldering is necessary for temporary prototypes, while the header pins also support permanent soldered connections.