3×4 Membrane Matrix Keypad

This small 4 button membrane matrix keypad allows control buttons to be added to a project with as little programming and soldering as possible.

Features of the 4×3 Matrix Keypad:

Keypads are one of the most popular components that are widely used in electronics. Everybody can communicate with the system by switches. Normally, every key occupies one digital pin of the microcontroller. But by using a 3×4 keypad you can reduce the occupied pins. With this module, you can use all 12 switches by occupying only 7 pins of the microcontroller.

How it works:

The Keypad 4×3 features a total of 12 buttons in Matrix form. Consider 4 rows as input and 3 columns as output. Each switch is connected from one side to a row and from the other side to a column. For example, if we press switch number 1, the input of this row is saved at the output of its column. The image below shows the internal circuit of this keyboard.

4×3 Matrix Keypad Pinout

This module has 9 pins:

ROW1: Input pin – Row 1
ROW2: Input pin – Row 2
ROW3: Input pin – Row 3
ROW4: Input pin – Row 4
COL1: Output pin – Column 1
COL2: Output pin – Column 2
COL3: Output pin – Column 3
NC: Not used