The smaple code of this button module is in the folder “4*4 button experiment”. Firstly, you need to unzip class library file “Keypad.zip” and place it in subfolder “libraries” of folder “Aduino” .

Codes are as below:

#include

const byte ROWS = 4; // define row 4

const byte COLS = 4; // define column 4

char keys[ROWS][COLS] = {

{‘1′,’2′,’3′,’A’},

{‘4′,’5′,’6′,’B’},

{‘7′,’8′,’9′,’C’},

{‘*’,’0′,’#’,’D’}

};

// connect row ports of the button to corresponding IO ports on the board

byte rowPins[ROWS] = {2,3,4,5};

// connect column ports of the button to corresponding IO ports on the board

byte colPins[COLS] = {6,7,8,9};

// call class library performance function of Keypad

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

void setup(){

Serial.begin(9600);

}

void loop(){

char key = keypad.getKey();

if (key != NO_KEY){

Serial.println(key);

}

}

5. Upload the program

According to arduino tutorial, upload the program to the board.

6. Program fuction

Upload the program to the board, open serial monitor; press certain button on the module, it will