1. Wireless Message Communication Between Two Computers

2. Wireless Message Communication between Two Computers
Introduction
The aim of this project is to develop a system for wireless message communication between two computers using 2.4 GHz trans-receiver units.
In offices, communication between employees is essential.
This project uses a pair of 2.4 GHz transceiver modules duly powered by 5 volt DC and alarm circuits.
They are used for bidirectional real time chat communication from one PC to another wirelessly using hyper terminal.

3. Wireless Message Communication between Two Computers
Description
The user attempts to initiate a chat, intimation upon that message is received first by a buzzer sound.
There after the other user can start communicating over the chat mode from his PC.
A pair of transceiver modules are connected to the PCs using a DB9 (De-Sub) connector and through serial data cord using RS232 protocol communication between the module and the PC.
An on-board dedicated ac to dc power supply is used at both ends to power the units.

4. Wireless Message Communication between Two Computers
Block Diagram

5. Wireless Message Communication between Two Computers
Hardware Requirements
2.4GHz transceiver
Resistors
Capacitors
Diodes
Transformer
Voltage Regulators
555 timers
Transistor
Buzzer

6. Wireless Message Communication between Two Computers
MAX 232
The MAX232 is an integrated circuit that converts signals from an RS-232serial port to signals suitable for use in TTL compatible digital logic circuits.
The MAX232 is a dual driver/receiver and typically converts the RX, TX, CTS and RTS signals .
When a MAX232 IC receives a TTL level to convert, it changes a TTL Logic 0 to between +3 and +15V, and changes TTL Logic 1 to between -3 to -15V, and vice
versa for converting from RS232 to TTL.

7. Wireless Message Communication between Two Computers
DB9 CONNECTOR
The DB9 (originally DE-9) connector is an analog 9-pin plug of the D-Sub miniature connector family (D-Sub or Sub-D).

8. Wireless Message Communication between Two Computers
555 TIMER
The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications.
The original name was the SE555 (metal can)/NE555 (plastic DIP) and the part was described as "The IC Time Machine".
Depending on the manufacturer, the standard 555 package includes over 20 transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-in-line package (DIP-8).

9. Wireless Message Communication between Two Computers
PIN DIAGRAM OF 555
The 555 timer IC is a simple 8 pin DIL package IC.
It can:
Be used as a monostable
Be used as an astable
Source or sink 100mA
Use supply voltages of 5v to 15v
Disrupt the power supply - use a decoupling capacitor

10. Wireless Message Communication between Two Computers
Pc Communication

11. Wireless Message Communication between Two Computers
Plug-and-communicate (no configuration required).
Transparent operation supports existing software & systems.
Simple configuration using software & standard AT commands.
Retries & acknowledgements for guaranteed packet delivery.
RS-232/422/485 protocol & multi-drop bus support.
Peer-to-peer, point-to-point & point-to-multipoint networks.

12. Wireless Message Communication between Two Computers
Future Scope
This concept in future can be further enhanced to link more number of systems forming a network.
To dedicated computers such that number of employees can communicate with each other.
Wireless message communication between two computers works only on operating systems having hyper terminal (E.g. Windows XP). The computer must have a RS232 serial port.