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Published September 17, 2018 © GPL3+

Making a Wireless Keyboard Using Arduino and Zigbee

How to make a wireless keyboard using Xbee with Arduino? This particular project demonstrates how to transmit the data from a PS2 keyboard.

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Making a Wireless Keyboard Using Arduino and Zigbee

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Group all Htabs Arduino

Description

The mouse and the Keyboard form the standard input unit for a Personal computer. The QWERT keyboard which is used in the PC comes with a PS2 connector or USB port connector. The PS2 keyboard uses a simple synchronous serial protocol using only two wires for communication. Due to its simplicity the PS2 keyboards are widely used with simple microcontroller based boards also. The PS2 keyboard always acts as a slave device which can send the equivalent ASCII value of the key which has been pressed to its master device which can be a PC or a microcontroller.

The ZigBee is the name of a wireless protocol maintained by the IEEE 802.15 standard. This is a protocol specified for wireless Personal Area Network (PAN) using low powered wireless transceivers. There are already wireless transmitter and receiver modules which can do point to point communication. The Xbee is the brand name a wireless transceiver device which works on the ZigBee protocol and can form PAN networks.

Xbee modules have an approximate range of 100 meters and are used in industries, scientific fields, medical fields etc. The Xbee module even though uses complex packet data based Zigbee protocol for communicating with each other, they can communicate with other devices using simplest serial communication protocol and hence they are widely used in microcontroller base boards. This particular project demonstrates how to transmit the data from a PS2 keyboard to a remote computer using Xbee transceivers.

Any AVR microcontroller based board which follows the standard Arduino schematic and is flashed with the Arduino bootloader can be called an arduino board. The arduino boot-loaderenables different Arduino boards to be connected and programmed with the Arduino IDE. The Arduino board used in this project is the Arduino pro-mini board and the IDE version of the arduino is 1.0.3 for windows.

The image of the Arduino pro-mini board and the Arduino IDE are shown below:

Fig. 2: Typical Arduino Pro-Mini Board

Fig. 3: Arduino IDE Software Window

Since the Arduino pro-mini board has no circuitary for interfacing it with the serial port or the USB port of the PC, an external USB to TTL converter board is required to connect it with the PC. This hardware helps in programming the Arduino board and also helps in the serial communication with the USB port of the PC.

Fig. 4: External USB to TTL converter board for programming Arduino and serial communication

It is assumed that the reader has gone through the project how to get started with the Arduino and tried out all the things discussed there. The image of the Xbee S1 series module used in this project is shown in the following image. Since the pitch of the pins of the modules are not breadboard compatible one can use the Xbee based design boards which comes with breadboard compatible pins.

Fig. 5: Xbee S1 Series Module

Since the Xbee modules communicate using serial communication protocol with the interfacing devices they can be connected to a microcontroller using a minimum of four pins, Power supply, and Ground, UART Data Out, and UART Data In pins. The Xbee modules have several digital and analog I/O pins apart from these pins and the pin out of an Xbee module is shown in the following table:

PIN

DESCRIPTION

Power Supply

UART Data Out

UART Data In

Digital Output 8 (not supported as of 2/28/09)

Module Reset (reset pulse must be at least 200 ns)

PWM Output 0 / RX Signal Strength Indicator

PWM Output 1

Do not connect

DTR / Pin Sleep Control Line or Digital Input 8

Ground

Analog Input 4 or Digital I/O 4

Clear-to-Send Flow Control or Digital I/O 7

Module Status Indicator

Voltage Reference for A/D Inputs

Associated Indicator, Analog Input 5 or Digital I/O 5

Request-to-Send Flow Control, Analog Input 6 or Digital I/O 6

Analog Input 3 or Digital I/O 3

Analog Input 2 or Digital I/O 2

Analog Input 1 or Digital I/O 1

Analog Input 0 or Digital I/O 0

Fig. 6: Pin Out of Xbee module

Since the Xbee modules communicate using serial communication protocol with the interfacing devices they can be connected to a microcontroller using a minimum of four pins, Power supply, and Ground, UART Data Out, and UART Data In pins.The pin number 2, UART Data Out is connected to the RX1 pin of the Arduino pro mini board and pin number 3 UART Data In is connected to the TX0 pin.

The keyboard always has 6 pin mini-DIN male connector for PS2 interface and the host device always has the corresponding female pin. The images and the pin-outs of the PS2 male and female connectors are shown in the following image, the only difference between the PS2 keyboard and mouse connectors are in their color.

The image of the PS2 male pin

Fig. 7: 6 Pin Mini-DIN Male Connector For PS2 Interface

The image of the PS2 female pin

Fig. 8: 6 Pin Mini DIN Female Connector Plug for PS2 interface

The pin-out of the PS2 male and female connectors

Fig. 9: Pin-Out Of PS2 Male Connector and Pin-Out Of PS2Female Connectors

When it comes to connecting the female connector with the circuit board one should be able to identify the pins at the bottom of the PS2 connector and the following image will be helpful.

Fig. 10: Bottom of Mini DIN Female Connector Plug for PS2 interface

The implementation of the project which can receive the data from the PS2 keyboard and transmit the characters one typed on the keyboard to a remote computer through Xbee is represented using the following block diagram:

Fig. 11: Block Diagram Of Data Transmission bewteen Keyboard and Computer Using Xbee

The code written for this project reads the data from the PS2 keyboard using the custom PS2 library file called “PS2Keyboard.h” which has all the necessary routines for accessing a PS2 keyboard. The details of how to use this library to interface a PS2 keyboard is already discussed in a previous project on how to interface the PS2 keyboard with the Arduino. There are basically three functions which the user can directly make use in their code and are namely “keyboard.begin()”, keyboard.available() and “keyboard.read()”. The details of the functions are discussed in the following.

keyboard.begin()

The function keyboard.begin() is used to perform all the necessary things to initialize an ASCII keyboard using PS2 protocol. Once the initialization is done properly each time a key is pressed the keyboard starts sending the equivalent ASCII value of the key which has been pressed. The function takes one parameter and it is the number of the pin in the Arduino board which acts as the Data pin of the keyboard.

keyboard.available()

This function can be used to check if a data regarding a key press is available from the keyboard. This function is always called before calling the keyboard.read() function which is used to read the data from the keyboard. The function returns a non-zero positive value whenever a key press is detected.

keyboard.read()

The function keyboard.read() can be used to read the ASCII value of a key which has been pressed from the keyboard. The function does not take any parameter and it returns the ASCII value of the key. The function keyboard.read() is always called after the function keyboard.read() returns a non-zero positive value.

The Arduino board writes the PS2 keyboard data to the Xbee for transmission with the help of serial communication functions provided by the Arduino library. The functions like Serial.begin() which helps to initialize the serial port with a given baud rate, Serial.write() to send a data to the serial port, Serial.available() and Serial.read() functions to read data from the serial port are used in this project and they are already discussed in previous projects on how to do serial communication with the Arduino, how to send and receive serial data using arduino and how to do serial debugging with the Arduino. The method of interfacing a Xbee module and transmission of data using it is discussed in as previous project on how to interface Xbee module with Arduino.

When the coding is finished one can verify and upload the code to the Arduino board as explained in the project how to get started with the Arduino. As soon as the board is powered up the Xbee in the Arduino board automatically establishes communication with another Xbee which is connected to the serial port of a PC. The second Xbee board can be connected to the PC using the same USB to TTL converter board which has been used to program the Arduino board. The letters typed on the PS2 keyboard will get transmitted and can be read on the PC using any serial monitoring software or using the Arduino IDE’s serial monitoring software itself as explained in the project how to do serial debugging with the Arduino.

Components

109, 275-Reads

Arduino Pro Mini

The Arduino Pro Mini is an ATmega168 based microcontroller board. The board comes with built-in arduino bootloader. It has 14 digital input/output pins (of which 6 can be used as PWM...

66, 918-Reads

LED

Light emitting diodes

...

48, 878-Reads

Resistor

Resistor is a passive component used to control current in a circuit. Its resistance is given by the ratio of voltage applied across its terminals to the current passing through it. Thus a particular value of resistor, for fixed voltage, limits the current through it. They are omnipresent in...

39, 876-Reads

Potentiometer

Potentiometer (Pot) is another class of variable resistors and is used as an adjustable voltage divider. It consists of a fixed resistance track having connections at both ends and a sliding contact, called wiper, which moves along this track by turning the spindle. If only one of the connections and wiper are used, it behaves as...

23479 reads

Code

Demonstration on How to Wirelessly send PS2Keyboard Data Using Xbee

/*============================ EG LABS ===================================//

 Demonstration on how to wirelessly send ps2keyboard data using Xbee


 The circuit:

 LCD:

 * LCD RS pin to digital pin 12

 * LCD Enable pin to digital pin 11

 * LCD D4 pin to digital pin 7

 * LCD D5 pin to digital pin 6

 * LCD D6 pin to digital pin 5

 * LCD D7 pin to digital pin 4

 * LCD R/W pin to ground

 * 10K resistor:

 * ends to +5V and ground

 * wiper to LCD pin 3

 * LED anode attached to digital output 9

 * LED cathode attached to ground through a 1K resistor


 KEYBOARD:

 DATA PIN TO PIN NUMBER 8

 CLOCK PIN TO PIN NUMBER 3


 XBEE:

 RX PIN OF XBEE TO TX0 PIN OF ARDUINO

 SHORT THE GROUND PINS OF ARDUINO AND XBEE

============================== EG LABS ===================================*/


#include "PS2Keyboard.h"

// include the library code:

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins

LiquidCrystal lcd(12, 11, 7, 6, 5, 4);


#define DATA_PIN 8

PS2Keyboard keyboard;


void setup() 

{

  pinMode(9, OUTPUT);     

  lcd.begin(16, 2);

  lcd.print("ENGINEERS GARAGE");

  lcd.setCursor(0, 1);

  lcd.print("KEYBOARD to XBEE");

  

  keyboard.begin(DATA_PIN);                        // initialize the PS2 keyboard


  Serial.begin(9600);

  Serial.println("ENGINEERS GARAGE");

  delay(1000);

  digitalWrite(9, HIGH);  

}


void loop()

{

  if(keyboard.available())            // check if there is any data coming from the keyboard

  {

    char dat = keyboard.read();             // read the data from the keyboard

    Serial.write(dat);

  }else;

}

Credits

TechnicalEngineer

4 projects • 49 followers

Making a Wireless Keyboard Using Arduino and Zigbee

Story

Group all Htabs Arduino

Schematics

Project-On-Wireless-Keyboard-Using-Xbee-Arduino-Circuit

Code

Demonstration on How to Wirelessly send PS2Keyboard Data Using Xbee

Credits

TechnicalEngineer

Comments

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Making a Wireless Keyboard Using Arduino and Zigbee

Making a Wireless Keyboard Using Arduino and Zigbee

Story

Group all Htabs Arduino

Schematics

Project-On-Wireless-Keyboard-Using-Xbee-Arduino-Circuit

Code

Demonstration on How to Wirelessly send PS2Keyboard Data Using Xbee

Credits

TechnicalEngineer

Comments

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