Membranes 3 × 4 Matrix Keypad extras - 3 × 4

Description

Punch in your secret key into this numeric matrix keypad. This keypad has 12 buttons, arranged in a telephone-line 3 × 4 grid. It's made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything. The keys are connected into a matrix, so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad. Check the tutorials tab for links to an Arduino library and example code.

We include a 7 extra-long header strip so you can plug this into a breadboard with ease.

Weight: 7.5 grams
Keypad dimensions: 70mm x 77mm x 1mm (2.75 ″ x 3 ″ x 0.035 ″)
Length of cable + connector: 85mm
7-pin 0.1 ″ pitch connector

There is a very nice Matrix Keypad Arduino library that works great with this item. The only thing we suggest is to change the initialization code in the examples to this:
#include "Arduino.h"
#include "Keypad.h"

const byte ROWS = 4; // four rows
const byte COLS = 3; // three columns
char keys [ROWS] [COLS] = {
{'1', '2', '3'},
{'4', '5', '6'},
{'7', '8', '9'},
{'*', '0', '#'}
};
byte rowPins [ROWS] = {8, 7, 6, 5}; // connect to the row pinouts of the keypad
byte colPins [COLS] = {4, 3, 2}; // connect to the column pinouts of the keypad

Keypad keypad = Keypad (makeKeymap (keys), rowPins, colPins, ROWS, COLS);

This will swap the * and # keys and also let you connect to the Arduino to match this image

Product information