Two Arduino's Communication with USART

In following schematic shows the connections to establish communication between two arduino's using Hardware Usart Arduino Uno connected to the keyboard scans the human inputs using keyboard and send the keystrokes as it is to the second arduino which shows the entered data.

Code for arduino connected to the Keypad (Tx) is :

#include <Keypad.h>

const byte ROWS = 4; // Four rows

const byte COLS = 3; // Three columns

// Define the Keymap

char keys[ROWS][COLS] = {

  {

    '1','2','3'  }

  ,

  {

    '4','5','6'  }

  ,

  {

    '7','8','9'  }

  ,

  {

    '*','0','#'  }

};

// Connect keypad ROW0, ROW1, ROW2 and ROW3 to these Arduino pins.

byte rowPins[ROWS] = { 

  5,4,3,2 };

// Connect keypad COL0, COL1 and COL2 to these Arduino pins.

byte colPins[COLS] = { 

  6,7,8 }; 

// Create the Keypad

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

#define ledpin 13

void setup()

{

  Serial.begin(9600);

}

void loop()

{

  char key = kpd.getKey();

  if(key)  // Check for a valid key.

  {

    Serial.print(key);

  }

}

we need arduino Keyboard library to compile the above code, can be found http://playground.arduino.cc/code/keypad

Arduino Connected to the Virtual Terminal(Rx) is:

#define password 123

#include<SoftwareSerial.h>

SoftwareSerial mySerial(10,11);//10-Rx  11-Tx

char data_buffer[15];

boolean read_data = false;

byte index;

void setup()

{

  Serial.begin(9600);

  mySerial.begin(9600);

  mySerial.println("welcome");

  mySerial.println("please enter password with starting letter * and ending letter # like *123#");

}

void loop(){

  if(Serial.available())

  {

    char input = Serial.read();

    if (input == '*')

    {

      read_data = true;

      index = 0;

    }

    else if(input == '#')

    {

      data_buffer[index] = 0;

      read_data  = false;

      mySerial.print("the value value you entered is");

      mySerial.println(atoi(data_buffer));

      if (atoi(data_buffer) == password){

        mySerial.println("password Matched");

      }

      else{

        mySerial.println("wrong Password");

      }

    }

    else

    {

      if(read_data)

      {

        data_buffer[index] = input;

        index = index + 1;

      }

    }

  }

}//end of loop

please see the video below to see how the schematic is done