26-11-2012, 04:01 PM
PC-MC BASED WIRELESS COMMUNICATION
1PC-MC BASED WIRELESS.DOC (Size: 370.5 KB / Downloads: 32)
Introduction
Computers and the related technologies are becoming more and more ubiquitous.
Various technical arenas in the field of Computer Science and Engineering, or Information Technology have come very near to the common people. The number of homes with Personal Computers is gradually increasing. A day will come, somewhere in the long future, when PC is referred to in the same class of Food, clothing and shelter". Improvements in the Networking technologies have fostered growth of very dense networks. Land line telephones have been becoming less and less popular and people now prefer communicating while on the move.
A Remote Control is perhaps the most popular gadget today. Right from the intense creativity of remotely controlling laser chip markers to the highly destructive remotely ignitable bombs, from the pins to the planes, remote control is not only occupying a omnipresence state, but is also enhancing its scope and domains.
When people have a good connectivity at their disposal, with tremendous power of mobile computing to supplement the same, we can think of connecting their home appliances to the personal computer or a laptop". With this, people would be able to turn on and off, and to some extent, control the appliances at their home even from a distant place. One of the very basic examples of an utility of this is switching on the air conditioner in the room just some time before reaching home, so that the room is sufficiently cool by then.
Personal computer:
PC is the main element of the communication between the PC and the Micro Controller, PC sends the data to be transmitted to the receiver side device, but the data cannot be transmitted directly from the computer, so it employs a serial communication with the Micro Controller. This requires a Micro Controller to be connected to the PC, so that it is programmed in order to receive data from the computer and transmit the data to the receiver section through the transmitting antenna.
Micro Controller:
The micro controller is a programmable device that performs a specific task. In the transmitter section of the arrangement, the microcontroller is used to receive data from the personal computer and the data is transmitted further through the transmitter. The micro controller operates on +5volts that is provided by the power supply.
The communication between the microcontroller and the pc is serial and this is done using the connector ‘RS 232’ that receives the data from the hyper terminal of the pc.
The RS 232 and the microcontroller has a difference in the voltage levels for the binary digits 0 and 1. So we employ MAX 232, a TTL converter between them, so that the data is received by the microcontroller is valid. The TTL converter converts the voltage levels of the RS 232 to match to that of the microcontroller.
Power supply:
The microcontroller needs a +5 volts DC voltage supply to operate its internal flip flops and other circuits. The voltage can be supplied from a DC voltage source or through a converter that converts the AC to +5 volts DC voltage.
In order to supply the DC voltage, we employed a Bridge rectifier that converts the AC to DC and the output of the rectifier could not be taken directly due to the fluctuations of the voltage levels of the converted signal, to overcome this, a voltage regulator is employed that converts the pulsated voltage into +5 volts that could be fed to the microcontroller.
Transmitter:
The main objective of the project is to see that the data transmission from one point to other is made possible. This needs a transmitter and a receiver, the transmitter takes the data from the microcontroller and transmits the data to the receiver side where the receiver receives the data. We employ an RF module, which operates at a predetermined RF frequency. The transmitter and the receiver must be synchronized.
The range of the communication of the wireless communication is directly proportional to the size of the antenna employed at the transmitter and receiver sides. The RF transmitter employed also needs a voltage feed of +5 volts to modulate the data received from the microcontroller to avoid the interference of noise and other signals. Depending upon the employed RF module, different type of modulation like OOK (on-off keying), amplitude modulation, or frequency modulation is done.
Receiver:
In the receiver section, the receivers play a vital role of receiving the data transmitted by the transmitter from the air. This must be very effective in receiving the modulated signal from the transmitter and performing the demodulation on it and sending the data to the microcontroller.
The receiver, similar to that of the transmitter needs a supply feed to demodulate and transfer the data to the microcontroller, this is done by the power supply at the receiver section.