Input Device of Computer

What is peripheral?

v  Devices that connects to a system unit and is controlled by the Central Processing Unit (CPU) in the computer

•         What is input ?

•          Any data or instructions entered into memory of computer

What are the two types of input?

v  Data

Ø  Unprocessed text, numbers, images, audio and video

v  Instructions

Ø  Programs

Ø  Commands

Ø  User responses

•         What are input devices ?

•          Input devices is any hardware component that allows an user to enter data or instructions into a computer

The categories of input devices:

•          The keyboard

•          Pointing devices

•          Scanners and Reading devices

•          Input devices for the physically challenged users

•         What is a keyboard?

•          An input device that contains keys, users press to enter data into a computer system.keyboard Converts letters, numbers and other characters into electronic signals that are machine-readable.

                       It is a 8-bit code (ASCII-8) or able to accommodate 256 different

                     Characters.

•          Desktop computer typically have from 101 to 105 keys

•         Required by software with Command Line Interface (CLI)

•         How is the keyboard divided?

•          Typing area

•          Numeric keypad

•          Function keys, special keys that issue command

•            The types of keyboards:

v  QWERTY

v  DVORAK

v  Enhanced keyboard

v  Wireless keyboard

v  Portable keyboard

v  Laptop keyboard

v  Handheld keyboard

v  Ergonomic keyboard

v  Virtual keyboard

v  QWERTY keyboard

v  The most widely used type of keyboard, so named because the first letters on the top alphabetic line spell QWERTY

v  DVORAK keyboard

v  A type of keyboard that places frequently types letters in the middle of the typing area

          Enhanced keyboard

v  A keyboard that has 12 function keys along the top : 2 Control (CTRL) keys and 2 Alternate (ALT) keys along the bottom and a set of arrow keys and other additional keys between the typing area and the numeric keypad

       Wireless or Cordless keyboard

v  Battery-powered keyboard that transmits data using wireless technology, such as radio waves or infrared light waves

•         Portable keyboard

•          A full sized keyboard, that an end-user conveniently can attach or remove from a handheld computer or PDA

•         Laptop and Handheld keyboard

•          Notebook and many handheld computers have built-in keyboards

•           Ergonomics keyboard

v  Design to minimise strain on hands or wrists

v  Ergonomics incorporates comfort, efficiency and safety into design of items of workplace

•         Virtual keyboard.

        Projects infrared image of keyboard onto any flat surface

•         What is a pointing device?

v  An input device that allows the user to control a pointer on the display screen

v  Required by software with Graphical User Interface (GUI)

•         The types of pointing devices

•          Mouse

•          Trackball

•          Touchpad

•          Pointing stick

•          Joystick and Wheel

•          Light pen

•          Touch screen

•          Stylus or Digital pen

•         What is a Mouse ?

•          Pointing device that fits under palm of hand

•          Pointing device controls movement of pointer, also called mouse pointer

•          A pointer on screen takes several shapes

 The types of pointing devices :

•          Mechanical mouse

•          Optical mouse   

•          Cordless mouse

•          How does a mechanical mouse work ?

•          Rubber or metal ball is on its underside

•          Movement of mouse translates into signals that computer understand

•         How does an optical mouse work ?

•          Senses light to detect mouse’s movement

•          More precise than mechanical mouse

•          Connect using a cable or wireless

•         Wireless or Cordless mouse

•         What is a trackball ?

•          Stationary pointing device with a ball on its top

•          To move pointer, rotate ball with thumb, fingers or palm of hand.

What is a Touch pad?

•          Touch pad is small, flat, rectangular pointing device that is sensitive to pressure and motion. It Often used in laptop computers.

•          What is a pointing stick?

•          Pointing stick is pointing device shaped like pencil eraser positioned between keys on keyboard

•          Moves pointer as pressure is applied

•          Often used in laptop computers

•         What are a joystick and a wheel?

•          Joystick

•          Is vertical lever mounted on a base

•          It enables the user to move within the screen’s environment

•          Widely used in computer games industry

•          Wheel

•          Wheel is steering-wheel-type input device

•          Users turn the wheel to simulate driving a car, truck etc.

•          Most wheels also include foot pedals to simulate car brakes and accelerator

•          What is a light pen?

•                     Handheld input device that can detect light

•          Press light pen against screen surface and then press button on pen

•         What is a Touch screen ?

•          Monitor has a touch-sensitive panel

•          Touch areas of screen with finger

•          Used to issue simple commands or choose from a list of options

•          Often used with kiosk

•          What is a stylus or digital pen ?

•          Looks like a ballpoint pen, but uses pressure to write text and draw lines

•          Used with graphics tablets, flat electronic boards and handheld computers

 

•          What is an Electronic signature ?

•          Is a legal signature created using special software, stylus and graphics tablet

•          Also called as e-signature

•    What is a scanner ?

•          Light-sensing device that captures data directly from source document

•          Source document is original form of data (printed text or graphics)

•          Used for image processing, converting paper documents into electronic images

•          What is an optical reader?

•          Device that uses light source to read characters, marks and codes and then converts them into digital data

•          What is an OCR font?

•          OCR device determines characters’ shapes by detecting patterns of light and dark

•          OCR software converts shapes into characters the computer can understand

•         What is a turnaround document?

•          It is a document that after being output by the computer can be used to record data and this data can then be input to the computer using a document reader

•          Portion you return has information printed in OCR characters

•          What is an Optical Mark Recognition (OMR) ?

•          Reads hand-drawn pencil marks such as small circles or rectangles

•          Used for ballots, enrollment application, attendance, questionnaires, course evaluation and multiple choice tests and examination

•          What is a Bar code?

•          Identification code that consists of a set of vertical lines and spaces of different widths

•          The symbol of the Universal Product Code (UPC)

•           What is a Bar code scanner?

v  Uses laser beam to read bar codes

• What is a Magnetic-Ink Character Recognition (MICR) reader?

v  Can read text printed with magnetized ink

v  Banking industry almost exclusively uses MICR for cheque processing

•          What is Biometrics?

•          Authenticates person’s identity by verifying personal characteristic

•          Fingerprint scanner captures curves and indentations of fingerprint

•          Hand geometry system measures shape and size of person’s hand

•          What are examples of Biometric technology?

•          Voice verification system compares live speech with stored voice pattern

•          Signature verification system recognizes shape of signature

•          Iris recognition system reads patterns in blood vessels in back of eye

•          Biometric data is sometimes stored on smart card, which stores personal data on 

            microprocessor embedded in card.