Input Device of a Computer System

Input devices in computer is devices which used for giving input to CPU (Central Processing Unit).

INTRODUCTION COMPUTER H/W

Simple hardware and their attachment in a typical PC is shown In the figure. The  input  devices  are  the  hardware  that  allows  us  to  put  information  into  a  computer.

IMPORTANCE  OF INPUT  DEVICES

Input devices play a major role in the processing of any data via the computer system because the output of the computer is always based on the given input. Generally, data, which is given to the input devices, is row. Therefore, it is the function of the input devices to manipulate the raw data and then send it for further processing. The preparation of input is the initial step in the creation of useful information.

TYPE OF INPUT DEVICES

• Key Board
• Mouse
• Track Ball
• Joy Stick
• Scanner
• Magnetic Ink Character Recognisation (MICR)
• Optical Character Reader (OCR)
• Optical Mark Reader (OMR)
• Bar Code Reader (BCR)
• Speech Recognisation
• Digitizing Tablet
• Digital Camera
• Touch Screen
• Touch Pad
• Light Pen

Key Board

KEYBOARD

Keyboard is the most common data entry device. Using  a  keyboard , the  user  can  type  text  and  execute  commands . keyboard  is  designed  to  resemble  a  regular  typewriter  with  a  few  additional  keys . Data is entered into computer by simply pressing various keys. The  number  of  keys  on  a  typical  keyboard  varies  from  82  keys  to  108  keys . custom  keyboards  that  have  slightly  different  key  arrangements  than  a  standard  keyboard .

Parts of Keyboard

Layout of keyboard :  The  layout  of   the  keyboard  can  be  divided  into  the  following  five  sections:

• Typing Keys
• Function Keys
• Numeric Keypad
• Control Keys
• Special Purpose Keys

MOUSE

Mouse  is  a  small  hand-held  pointing  devices , which  is  rectangular-shaped  with  a  rubber  ball  embedded  at  its  lower  side  and  buttons  on  the  top . The  Mouse  may  be  classified  as  a  mechanical  mouse  or  an  optical  mouse , based  on  technology  it  uses .

A  mouse  allows  us  to  create  graphic  element  on  the  screen , such  as  lines , curves ,and  freehand  shapes . It  is  much  easier  and  convenient  to  work  as  compared  to  the  keyboard.

Mouse

TRACK BALL

Trackball is another pointing device that resembles a ball nestled in a square cradle and serves as an alternative to a mouse. Like a mouse, a trackball is also used to control cursor movements and the actions on a computer screen. 

Track Ball

JOYSTICK

Joystick is a device that moves in all directions and controls the movement of the cursor. The joystick offers three types of control: digital, glide, and direct. Digital control allows movement in a limited numbers of directions such as up, down, left, and right.

A joystick is generally used to control the velocity of the screen cursor movement rather than its absolute position. 

Joystick

SCANNER

Scanner is a device used to make a soft copy of document or photo. It is just like a camera which takes snap of your document or photo and feed to computor.

Scanner

BAR CODE READER

Bar Code Reader is photoelectric scanners that read the Bar Codes, or vertical zebra striped marks, printed on product containers. Super market use a Bar Code system called the Universal Product Code (UPC)

The bard code identify the product to the super market’s computer, which has a descriptions and the latest price of the product. The computer automatically tells the POS (Point of sells) terminal what the price is?

Bar Code Reader

SPEECH RECOGNITION

Speech or voice input devices convert a persons speech into digital form these input devices, when combined with appropriate software, form voice recognition system. This system enables users to operate Micro Computers using voice commands.

There are two types of voice recognition systems:

• Continuous Speech
• Discrete Speech

Speech Recognition System

DIGITAL CAMERA

Images can be input into a computer using a digital camera. These images can then be manipulated in many ways using the various imaging tools available.

The digital camera takes a still photograph, stores it, and then sends it as digital input into the computer. The images are then stored as digital files.

Digital Camera

DIGITIZING TABLET

This is an input device that enables you to enter drawings and sketches into a computer. It comprise of a digitizing tablet and a cursor or pen.

A cursor (also called a puck) is similar to a mouse, except that it has a window with cross hairs for pinpoint placement, and it can have as many as 16 buttons.

Digitizing tablets are also called digitizers, graphics tablets, touch tablets, or simply tablets.

Digitizing Tablet

TOUCH SCREEN

Touch Screen is a type of display screen that has a touch sensitive transparent panel covering the screen.

Although Touch Screen provides a natural interface for computer novices, they are unsatisfactory for most application because the finger is such a relatively large object.

Touch Screen

TOUCH PAD

A small, touch-sensitive pad used as a pointing device on some portable computers.

By moving a finger or other object along the pad, you can move the pointer on the display screen.

Touch Pad

LIGHT PEN

Light pen is an input device that utilizes a light-sensitive detector to select objects on a display screen.

A light pen is similar to a mouse, except that with a light pen you can move the pointer and select objects on the display screen by directly pointing to the objects with the pen.

Light Pen