Membrane 3x4 Matrix Keypad

This key­pad has 12 but­tons, arranged in a tele­phone-line 3x4 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.TECHNICAL DETAILSWeight: 7.5 gramsKey­pad dimen­sions: 70mm x 77mm x 1mm (2.75″ x 3″ x 0.035″)Length of cable con­nec­tor: 85mm7‑pin 0.1″ pitch con­nec­torThere 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:Arduino #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 );123456789101112131415#include “Arduino.h”#include “Keypad.h” con­st byte ROWS = 4; //four rowscon­st byte COLS = 3; //three columnschar 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 key­padbyte 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