Arduino & 4x4 Matrix keypad

4x4 Keypad Pinout/Diagram

Arduino to Keypad Connection Diagram

After connecting as shown here we need to upload a code on our arduino. Here's the Code :

#include <Keypad.h>

const byte numRows= 4; //number of rows on the keypad

const byte numCols= 4; //number of columns on the keypad

char keymap[numRows][numCols]=

{

{'1', '2', '3', 'A'},

{'4', '5', '6', 'B'},

{'7', '8', '9', 'C'},

{'*', '0', '#', 'D'}

};

byte rowPins[numRows] = {9,8,7,6}; //Rows 0 to 3

byte colPins[numCols]= {5,4,3,2}; //Columns 0 to 3

//initializes an instance of the Keypad class

Keypad myKeypad= Keypad(makeKeymap(keymap), rowPins, colPins, numRows, numCols);

void setup()

{

Serial.begin(9600);

}

//If key is pressed, this key is stored in 'keypressed' variable

//If key is not equal to 'NO_KEY', then this key is printed out

//if count=17, then count is reset back to 0 (this means no key is pressed during the whole keypad scan process

void loop()

{

char keypressed = myKeypad.getKey();

if (keypressed != NO_KEY)

{

Serial.print(keypressed);

}