AICT001-3-1 Chapter 6: Input Devices - Answer

soilflippantAI and Robotics

Nov 17, 2013 (3 years and 11 months ago)

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1




AICT001
-
3
-
1

C
hapter
6
:

Input Devices

-

A
nswer



1.

Briefly differentiate between the following terms
:


a.

data and instruction

Data



Unprocessed text, numbers, images, audio and video

Instructions



Programs



Commands



User responses


b.

Program, command and user respon
d



Program: series of instructions that tells a computer what to so and how to
do it.

o




Commands: an instruction that causes a program to perform a specific
action.

o

Eg: click on mouse button, touch on screen, press a keyboard key.



User response : an instruc
tion a user issues by replying to a question
displayed by a program.

o

Eg: answer YES, NO, CANCEL


c.

QWERTY keyboard

and
DVORAK keyboard



QWERTY keyboard

o

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

QWERTY










DVORAK keyboard

o

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












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d.

pointing device and mouse



pointing device

o

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

o

Requi
red by software with Graphical User Interface (GUI)




Mouse

o

Pointing device that fits under palm of hand
.

o

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

o

As you
move, the pointer on the screen also moves
.

o

A pointer on screen takes s
everal shapes
.


e.

scanner and reading device



scanner : light sensing input device that reads printed text and graphics

and
translate the result into a form the computer can process.

o

Light
-
sensing device that captures data directly from source document

o

Source

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

o

Used for image processing, converting paper documents into
electronic images

o




Optical reader: a device that uses a light
source to read characters, marks
and codes and then convert them into dig
ital data that a computer can
process.

o

Eg: optical character recognition and optical mark recognition.


2.

List all the categories of input devices.

a.

The keyboard

b.

Pointing devices

c.

Scanners and Reading devices

d.

Input devices for the physically challenged users



3.

List different
types of
mouse and briefly explain how they work? Identify
several mouse operations.


a.

Mechanical mouse

o

Rubber or metal ball is on its underside

o

Movement of mouse translates into signals that computer
understand


b.

Optical mouse

o

No moving me
chanical parts inside

o

Senses light to detect mouse’s movement

o

More precise than mechanical mouse

o

Connect using a cable or wireless


c.

Cordless mouse

o

Communication with a receiver attached to a port on the
system unit



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4.

List other type of pointing device an
d how do they work?


a.

Trackball

o

Stationary pointing device with a ball on its top

o

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


b.

Touchpad

o

Touchpad is small, flat, rectangular pointing device that is sensitive to
pressure and motion

o

Often

used in mobile computers

o


c.

Pointing stick

o

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

o

Moves pointer as pressure is applied

o

Often used in mobile computers

o


d.

Light pen

o

Handheld input device that can detec
t light

o

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

o


e.

Digital pen

o


GAMES

o


f.

Game pad

o

Control pad on an audio player allows users to scroll through music,
adjust volume, and customize settings

o

Gamepad a pointing device that controls
the movement and actions of
players or objects in games

o


g.

Joystick

o

Joystick is vertical lever mounted on a base

o

Wheel is steering
-
wheel
-
type input device

o


h.

Light gun

o


i.

Dance pad

o



5.

What are input devices for PDA, tablet PC
,

smart phones
, kiosk
?


a.

PDA



S
tylus



Built
-
in keyboard



Voice input



Portable keyboard




b.

Tablet PC



Digital pen



Keyboard



Mouse



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c.

Smart phones



Camera



Whatever PDA have

d.

Kiosk



Touch screen



Keyboard


6.

Briefly explain different types of terminals.

Terminal consists of a keyboard, monitor, a video card
and memory.

a.

Dumb



no processing power



not independent device



accept input then transmit data to host, host process then return back (if
needed) to dumb terminal.

b.

Smart



Has processor



Process some function



Independent from host

c.

Special purpose terminal



Perfor
m specific task



Features uniquely design for use in a particular industry



Eg: POS (point
-
of
-
sale) and ATM.


7.

Define the term biometric
, biometric identifier
, biometric data

and biometric device
.

Identify various biometric devices and briefly explain their f
unction.


o

Biometric
-

A technology to a
uthenticate person’s identity by verifying personal
characteristic
. Use to access anything


o

biometric identifier


is a physiological (physic and chemical activities in body) or
behavioral characteristic eg: finger pr
ints, hand geometry voice


o

biometric device


translates a personal characteristic (input) into a digital code that
is compares with a digital code stored in the computer.

If not match, access deny.


o

Biometric data is sometimes stored on smart card, which
stores personal data on
microprocessor embedded in card



a.

Voice verification system compares live speech with stored voice pattern

b.

Signature verification system recognizes shape of signature

c.

Iris recognition system reads patterns in blood vessels in back o
f eye

d.

Face recognition


captures live face

e.

Hand geometry


measure the shape and the size of hand

f.

Retinal scanner


scan patterns of blood vessels in back of retina.


8.

Identify alternative input

devices for physically challenged users?



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Input device

a.

Keygua
rd allows users to rest hands on keyboard without accidentally pressing keys

b.

Head
-
mounted pointer controls pointer on screen

c.

gesture recognition



Computer will detect human motion



Computers with this

capability have potential to
recognise

sign language,
read lips, track facial movements or follow eye glazes


d.

computerized implant devices



For
paralysed

or speech impaired individuals



Doctor will implant
computerised

device containing transmitter into brain




As user thinks, transmitter will send signals

to computer