conceptual framework input devices

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Conceptual Framework

Unit 1

Computer Application and Management Information System; NMBA 018


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Input Devices◦ Keyboard,◦ Pointing Devices,◦ Voice Speech Devices,◦ Scanner,◦ MICR,◦ OMR,◦ Bar Code Reader,◦ Digital Camera

Topics to cover:


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An electromechanical device/peripheral used

• to provide data and • control signals to an information processing

system such as a computer or information appliance.

Examples: keyboards, mouse, scanners, digital cameras and joysticks, etc.

What are Input Devices?


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Keyboard


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Most popular for direct entry of data and instructions

Standard QWERTY keyboard is used Enhanced keyboard has 101keys Special keys - PageUp, PageDown, PrintScreen etc. Looks like electronic typewriter keyboard with

additional keys linked to the CPU and it is also linked to the computer screen so that the data entered into

the memory can be seen by the user as he types in the data

Keyboard


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Keys Description

Typing Keys • Include the letter keys (A-Z) and digit keys (0-9)

Numeric Keypad • Used to enter numeric data or cursor movement. • Generally, consists of a set of 17 keys

Function Keys • Twelve function keys• Each key has unique meaning and use

Control keys • Provide cursor and screen control• Includes four directional arrow keys• Also include Home, End, Insert, Delete, Page Up, Page

Down, Control(Ctrl), Alternate(Alt), Escape(Esc)

Special Purpose Keys • Special purpose keys such as Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, and Print Screen.

Types of Keys in a Keyboard


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Used to communicate with the computer by pointing to locations on the screen

Does not need keying of characters

Provides a cursor on screen to perform move, click, or drag operations

Examples – Mouse, Joystick, Trackball, Touch screen

Pointing Devices


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Mouse


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Small hand-held pointing device palm size box containing 3 buttons and a ball

underneath, which senses the movement of the mouse and sends the corresponding signals to CPU on pressing the buttons

used to move cursor on the screen, issue commands and select an option from group of choices.

allows to create graphic elements on the screen

Mouse


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Type DescriptionMechanical • Comprises of rubber ball at the bottom surface

• Mouse pointer moves on the screen when the ball rotates on the surface on moving the mouse

• Least expensiveOptical • Uses light beam to detect movement

• No need of regular cleaning as does not consist any moving part

• No chance of mechanical failureWireless • Mouse without wire/cord to connect to computer

• Communicates to computer using Radio Frequency (RF) technology

• Transmitter is fitted within the mouse and Receiver is a separate device that plugs into computer - a special card in an expansion slot or a built-in component

Types of Mouse


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Joystick


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Pointing device that moves in all directions and controls movement of cursor

Consists a stick attached to a plastic base with flexible rubber sheath

Provides three types of controls:◦ Digital: limited movement – up, down, left and

right◦ Glide & Direct: movements in all directions

including 360degrees◦ Direct control also responds as per the distance &

speed of the movement

Joystick


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Computer Games, Applications like Flight simulators and

training simulators CAD/CAM systems To control industrial robots In mobile phones

Uses of Joysticks


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A ball nestled in a square cradle Alternative to mouse as uses less desk

space When ball is rotated in any direction, cursor

moves in that direction on the screen

Trackball


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Hand-held electro-optical pointing device Helps in drawing images and selecting

objects on screen consists of a photocell and an optical

system placed in a small tube

Light Pen


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Special kind of display screen device Allows direct selection or activation of the

computer functions on touching the screen Registers the input when finger or other object

is placed on the screen Advantages

◦ minimum effort◦ No additional peripherals required

Disadvantages◦ Expensive◦ Not suitable for inputs of large amount of data

Touch Screen


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converts voice into electrical pulses and then into digital signals for onward transmission to a computer for processing.

Voice recognition systems are very useful in offices for word processing

manager can directly dictate letters and notes to word processor through a speech recognition system

can accept oral commands and execute them not popular due to storage of limited vocabularies

and variations in way of pronouncing words by different persons

Voice Speech Devices


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Converts text or image to an electronic representation viewed on the screen

Scans input data using light beam and transforms it into ASCII code and image

Bundled with software to communicate to computer and save as graphic files

Stores images in both greyscale and colour mode

Scanner


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reads the presence or absence of a mark on a paper optically

It is used to read multiple choice answers in a test and the data are transferred to a computer for processing.

OMR - Optical Mark Reader


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Uses highly stylised character shapes printed in a special ink containing particles that can be magnetised.

The MICR reader can only identify characters.

Banking industry uses this device for sorting of cheques

MICR - Magnetic Ink Character Recognition


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an optical scanner used for reading bar-coded data and converts it into electrical pulses

direct data entry device Bar-coded data is generally used in labelling

goods, numbering the books or encoding ID or A/c numbers

Bar Code Reader


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Stores images digitally rather than recording them on film

Uses memory card to store the images which can be seen later from the card

Advantage – making photos is inexpensive and fast

Digital Camera


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Assignment 11. What are different types of scanners?

Compare the advantages and disadvantages.

2. Write short note on:a) OMRb) MICRc) Bar Code Readerd) Digital Camerae) OCRf) Microphone

conceptual framework input devices

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