computer Education: 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