21-09-2012, 11:57 AM
Wireless Keyboard for Computer
WIRELESS KEYBOARD.doc (Size: 103 KB / Downloads: 44)
DESCRIPTION :
The main aim of this project is to transfer the data from keyboard to CPU without using physical serial cable. Data transfer from one place to other is communication. The communication is two types. Wired communication and another is wireless communication. This project is wireless communication using IR medium. In wired communication a physical serial cable is used to transfer the data. In normal keyboard data transmitted through the cable. This project is less cost compare to other medium which is used transmit the data.
TECHNOLGY :
Data Transmission is through IR which uses RC5 Protocol.
WORKING :
The communication between keyboard and computer is made through IR Medium. In this project two micro controllers is required. One at the transmitter which is inside the keyboard other at the receiver which inside the CPU. In IR transmitter, microcontroller receives the signal from the keyboard and it encodes that signal. This encoded signal is send to the IR transmitter; IR transmitter converts the encoded signal into light signal. At receiver end, the IR receiver receives this signal and converts it into the electrical signal. The microcontroller receives this electric signal and decodes it and performs the operation according to the received signal.
Vital Role of Micro Controller – AT89S52 in ‘Wireless Keyboard for Computer’
This is the main part of this project. During the transmission it receives the signal from keyboard. This encodes that received signal and transmitted in IR medium through the IR transmitter. At receiver end it receives IR signal from IR transmitter and then decode it. The decoded value it sends the signal to PC. Here two microcontrollers is used one at the transmitter and another at the receiver.
IR Transmitter
This IR led is used to emit the infrared rays at particular frequency. The emitting
light is not visible in human eyes.
The IR transmitter is inside the REMOTE control. One button is pressed it encode the value & sends that value in light signal.
IR Receiver
This receiver is used to receive the IR signal which is transmitted from IR transmitter. The IR receiver is inside the computer. It converts from the detected light signal to electrical signal. It decodes the received signal and then sends to the micro controller.
RS 232 Protocol
RS-232 was created for one purpose, to interface between Data Terminal Equipment (DTE) and Data Communications Equipment (DCE) employing serial binary data interchange. So as stated the DTE is the terminal or computer and the DCE is the modem or other communications device.
RS-232 pin-outs for IBM compatible computers are shown below. There are two configurations that are typically used: one for a 9-pin connector and the other for a 25-pin connector.