I2C Keypad

// I2C Keypad for Arduino
// Venkateswara Rao.E 
// 19-oct-2015
// Credits to  @author Alexander Brevig

#include <Wire.h>
#include <Keypad_I2C.h>
#include <Keypad.h>
#define I2CADDR 0x38

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','#'}
};

// Digitran keypad, bit numbers of PCF8574 i/o port
byte rowPins[ROWS] = {0, 1, 2, 3}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {4, 5, 6}; //connect to the column pinouts of the keypad

Keypad_I2C kpd( makeKeymap(keys), rowPins, colPins, ROWS, COLS, I2CADDR, PCF8574 );

void setup(){
	  Wire.begin( );
	  kpd.begin( makeKeymap(keys) );
	  Serial.begin(9600);
	  Serial.println( "start" );
}

void loop(){
	  char key = kpd.getKey();
	  
	  if (key){
		Serial.println(key);
	  }
}