Implementation of Wireless PC Communication System by using Transceiver

Technology is playing a vital role in our daily life. Advancement in wireless communication is the most actively growing technologies of our time. It has reduced the complexities that made human life easier. This technology has greatly influenced the telephonic system and internet technology.

Introduction to Wireless Communication

The transfer of information the points without any physical connections like cables is termed as wireless communication. It is a type of data communication system. In broad words, wireless communication uses signals for data transmission.

Wireless communication works through electromagnetic signals. These are broadcasted into the atmosphere through a device. The transmitting device can be a sender or an intermediate device which propagates wireless signals. The communication between the two devices occurs when the transmitter and the receiver capture the signal forming a wireless bridge between the devices. Wireless communications are of various types depending on the technology, ecosystem, and delivery method. Here are the different communication systems.

• Satellite Communication
• Wireless network communication
• Mobile communication
• Infrared communication
• Bluetooth communication

Though these communication technologies have unique architecture, they work on the transmission and receiving of the data wirelessly.

Wireless communication through Radio Frequency has many advantages as it does not require any line of sight connection between the transmitter and receiver while the line of sight connection exists in infrared communication. A wireless RF transmitter and receiver can be built using an HT12D Decoder, HT12E encoder, and an RF module. The range of RF communication is high relative to the IR communication. RF transmission is stronger and reliable than the IR transmission because

• The radio frequency signals can travel longer distances than the infrared signals.
• RF signals can be transmitted through the obstacle
• RF signals do not interfere with other RF signals over one frequency band.

Wireless Transmitter

HT12E is an encoder IC Which will convert the 4 bit parallel data given to pins D0 to D3 to serial data and at the output pin Dout. This output serial data are given to the RF transmitter. Address inputs A0 to A7 can be used to provide data security and can be connected to GND (i.e., logic ZERO) or left open (i.e., logic ONE).

The status of these address pins should match the address pins of the receiver for transmission of data. The data will be transmitted when the Transmit Enable pin (TE) is LOW. The resistor of 750KΩ will provide the external resistance for the operation of the internal oscillator in HT12E.

Wireless Receiver

An RF receiver receives the transmitted data from the RF transmitter. HT12D decoder will convert the received serial data to 4 bit parallel data D0 to D3. The status of the address pins A0 to A7 should match with the status of the address pins at HT12E for transmission of the data.

The LEDs connected to the circuit glows when valid data transmits from the transmitter to the receiver. A 33kΩ resistor will provide the necessary for the working of the internal oscillator of HT12D.

Wireless PC Communication System using Transceiver

The wireless PC communication system uses 2.4GHz trans-receiver to establish communication between the two computers. This system is used in offices for communication between the employees and the manager.

A wireless PC communication system uses a pair of 2.4GHz transceiver modules which is powered by 5 volts DC and an alarm circuit. This system is used for bi-directional real-time chat communication from one PC to another using the hyper terminal.

A pair of transceiver modules are connected to the PCs using a DB9 connector and a serial data cord using RS232 protocol is used for communication between the module and the PC. An onboard AC to DC power supply is used at both ends to power the units.

While one of the users attempts to initiate the chat, an intimation is created using a buzzer sound upon the receipt of the message. Thereafter, the other user can start communication over the chat mode from the PC. Wireless PC communication system project works only on operating systems having hyper terminal and the computer must have an RS232 serial port.

Block Diagram

Hardware Requirements

• 2.4GHz Transceiver
• Resistors
• Capacitors
• Diodes
• Transistors
• Transformers
• Voltage Regulator
• 555 Timers
• Buzzer

Circuit Operation

The circuit uses a standard power supply comprising of a step-down transformer from 230Vto 12V and 4 diodes forming a bridge rectifier that delivers pulsating DC which is then filtered by an electrolytic capacitor of about 470µF to 1000µF. The filtered DC being unregulated, IC LM7805, and LM1117 are used to get 5V DC constant at its pin no 3 irrespective of input DC varying from 7V to 15V.

555 Timer

A 555 timer is used to provide a time delay in various applications. The timer circuit consists of a 555 timer IC, resistor and capacitor combination, and a transistor. The timer circuit is connected to pin 14 of the microcontroller through a slide switch.

A 5V supply is given to pin 8 and 4 of the IC. The 555 timers are used in the astable mode to vary the frequencies. The timer circuit has a male pin connector to interface with the motherboard. Since the frequency cannot be changed, the 555 timer circuit is used to generate the artificial frequency

MAX232

The MAX 232 is an integrated circuit used as a voltage converter. This IC is used in communication systems where the voltage level conversion is required to make TTL devices to be compatible with RS 232 standards of PC serial ports and vice versa.

The controller operates at the TTL logic level (0-5v) while the serial communication PC works at RS232 standards (+25v to -25v). This makes it difficult to establish a direct link for communication. MAX 232 acts as an intermediate link between them. MAX 232 is a dual transmitter/receiver that is typically used to convert the RX, TX, CTS and RTS signals.

2.4GHz Transceiver

This is an RF-based 2.4GHz frequency transceiver designed for low power wireless applications. The RF transceiver is integrated with a highly configurable baseband modem. This is a low-cost device.

This concept is the future can be further enhanced to link a number of systems forming a network of computers so that a number of employees can communicate with each other.

Applications of wireless communication

• Wireless security systems
• Car alarm systems
• Sensor reporting
• Remote control
• Automation system

Thus, this is all about the Wireless PC communication system and its applications. We hope that you have got a better understanding of this concept. Furthermore, any queries regarding this topic or wireless communication projects, please give your valuable suggestions by commenting in the comment section below.

Here is a question for you, what is the main function of RS232?