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8/12/2019 Chap1.5 Input Devices
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The followin! are five simple techniBues which are used to carr$ out various
operations
% point ; means to move the mouse to the correct position' clic& ; to clic& means to press and release the left mouse #utton once It
allows the section of the menu item represented #$ the icon which is
currentl$ #ein! pointed to #$ the !raphics cursor The ri!ht cursor is usedto call up a menu options
( dou#le clic& ; means to press and release the left #utton twice inn rapid
succession It allows e>ecution of the pro!ram represented #$ the icon"which is currentl$ #ein! pointed to #$ the !raphics user
) simultaneous clic& ; means to press and release #oth the left and ri!ht
mouse to!ether The actual functionalit$ for simultaneous varies from
software pac&a!e to pac&a!e
+ dra! ; To dra! means to position the !raphics cursor over the !iven item"then depress the #utton and hold it down as the cursor is moved on the
screen 6ou ma$ dra! a icon to chan!e its location on the screen To draw!raphics o#*ects such as line" circles" curves etc
97: T/AC57A
It is similar to a mouse #ut its #all that is at the #ase of a mouse is place on the top
alon! with the #uttons in case of a tacall To move the !raphics cursor around thescreen "the #all is rolled with the fin!ers The whole device is not moved for movin! the
cursor hence the tracall reBuires less space than a mouse for the operation Thetracall #uilt in the &e$#oard are commonl$ used in APTPS The three commonl$used shapes for the #all are #utton" #all or a sBuare
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9C: 6STIC5
It is pointin! device that wor&s on the similar principle as the tracall To ma&e the
movement the spherical #all eas$" the spherical #all moves in a soc&et with a stic&
mounted on it The stic& can #e moved forward or #ac&wards " left or ri!ht and to theposition the cursor at the desired position The #utton on top is provided to select the
option" which is currentl$ pointed to #$ the cursor The #utton is clic&ed ot ma&e this
selection
DATA SCANNIN@ DEVICE
In order to reduce the possi#ilit$ of human error in data entr$" the data can #e entered
directl$ from the source document Data scannin! devices are input devices used fordirect data entr$ into the computer s$stem from source documents
=ith Data scannin! device followin! points to #e &ept in mind8
Eliminate some of the duplication of human efforts to !et the data in the computer
Improves data accurac$
The$ demand hi!h Bualit$ of input document
orm desi!n and in& specification #ecomes more critical
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9A: SCANNE/ 8 is an input device that translated paper documents into an electronic
format that can #e stored in a computer The input document ma$#e a t$ped te>t"
pictures" !raphics or even handwritten documentsIma!e scanners are also called optical scanners #ecause the$ use optical
technolo!$ for convertin! an ima!e into electronic form An intersection of a
hori2ontal and a vertical line of !raph is called the !rid point If there is a dar&point on the !rid point it is a % otherwise it is a 4 This is called a #it map
representation Each #it is the representation of the ima!e is called a pi>el
Ima!e scanner are of two t$pes8
9%: Flat bed scanner - it is li&e a cop$ machine consistin! of a #o>
havin! a !lass plate in its top and a lid that covers the !lassplate The document to #e scanned is place upside down on the
!lass plate
9': Hand held scanner8 has a set of li!ht emittin! diodes encased
in a small case that can #e convenientl$ held in hand durin!operation To scan a document the scanner is slowl$ dra!!ed
ver$ steadil$ and carefull$ over the document" therefore hand
held scanner are used onl$ in cases where hi!h accurac$ is notneeded
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97: ./ 9optical mar& reader: ; these scanners are capa#le to reco!ini2in! a pre-specified t$pe of mar& made #$ pencil or pen E>ample 8 man$ students mi!ht have
appeared in o#*ective t$pe tests where the$ had to mar& their answers to Buestions #$
a pencil to indicate their correct choice The answer sheets are directl$ fed to acomputer for !radin! with the use of an optical mar& reader
The actual techniBue used #$ an ./ device for reco!nition of mar&s involvesfocusin! a li!ht on the pa!e #ein! scanned and detectin! the reflected li!ht pattern
from the mar&s ./ needs
Pre printed forms need a !ood Bualit$ paper
7o>es to #e mar&ed in them accuratel$
The form should not #e folded
9C : 7A/ CDE /EADE/
Data is coded in the form of small lines 9&now as #ars: are &now as #ar codes 7ar codes
represents alphanumeric data #$ a com#ination of ad*acent vertical lines 9#ars: #$
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var$in! their width and spacin! #etween them A #ar code is reader is a device used for
readin!9decodin!: #ar coded data It ma$ #e hand held scanner or ma$ #e em#edded in a
stationar$ scanner It scans a #ar code ima!e and converts it into a an alphanumericvalue" which is then fed to the computer to which the #ar code reader is connected " *ust
as thou!h the alphanumeric value had #een t$ped on a &e$#oard
A #ar code reader uses a laser #eam scannin! technolo!$ The laser #eam is stro&edacross the patterns of #ars of a #ar code i!ht patterns are converted into electrical
pulses and then transmitted to reco!nition lo!ic circuits which converts it into an
alphanumeric value
7ar code readers are commonl$ found in supermar&ets and department stores
9D: .IC/ ;9ma!netic in& character reco!inition:
It is similar to C/ and is used #$ the #an&in! industr$ for faster processin! of thelar!e volume of cheBues #ein! handled ever$da$ 7an&s that emplo$ .IC/
technolo!$ use a special t$pe of cheBue The #an& identification code 9name " #ranch
etc: " account num#er" and the cheBue num#er are pre-printed 9encoded: usin!characters from a special character set on all these chec&s with a special in& that
contains ma!neti2a#le particles of iron o>ide #efore the cheBues are issued to the
customer
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9E: DI@ITIFE/
A di!iti2er is an input device used for convertin! 9di!iti2in!: pictures" maps"
Drawin! into di!ital form for stora!e in computers A di!iti2er consists of di!iti2in!
ta#let 9also &now as !raphics ta#let: associated with a st$lus The di!iti2in! ta#let is a flat
surface that contains hundreds of fine copper wire formin! a !rid Each copper wirereceives electric pulses The st$lus is li&e a pen or lens li&e cursor which converts the
pictures into the di!ital form Di!iti2ers are commonl$ used in the area of CAD
9computer aided desi!n: #$ the architects and en!ineers to desi!n cars"#uildin!s ro#ots
9: EECT/NIC CA/D /EADE/
The$ are small plastic cards havin! encoded data appropriate for the application for
which the$ are used An electronic card reader is connected to the computer which is
used to read the data encoded in the an electronic card and transfer it to the computerfor further processin!
Electronic cards are often used #$ #an&s and issued to customers for use in
AT. 9automatic teller machine: An AT. allows a customer to depositor withdraw cash ') hours a da$ without needin! to interact with the #an&
Electronic cards are also used #$ man$ ori!ani2ations for controllin!
access to ph$sicall$ secured area
The$ are of two t$pe
% ma!netic strip cards8 the$ have a ma!netic strip on their #ac&The data to #e encoded on the card is stored on the ma!netic
strip
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' smart card8 have #uilt in microprocessor chip instead f a
ma!netic strip" the data encoded on the card in permanentl$
stored in the memor$ of the microprocessor
9@: VICE /EC@INITIN DEVICE
The$ allow the person to input data to the computer s$stem #$ spea&in! to itThe$ have limited success #ecause the correct interpretation #$ the machine
of a lar!e num#er of words in a voca#ular$ of a lan!ua!e is difficult The
ma*or difficult$ has #een that people spea& with different accent and tones
It consists of an input device such as a telephone or a microphone that
converts human speech into electric si!nals
A si!nal pattern is sent to the computer where it is matched a!ainst the
pre-stored patterns to identif$ the input
=hen a close match is found" a word is reco!ni2ed #$ the s$stem
The set of pre-stored patterns is &now as the voca#ular$ of the s$stem
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9?: =E7 CA.E/A
A we# camera allow a computer to accept input *ust #$ focusin! on a o#*ect #$ ta&in!
its picture Picture so ta&en can #e transferred over the networ& to a distant placeIt creates an ima!e of an o#*ect in di!ital form9in %s and 4s: so that it can stored and
interpreted #$ the computer
9 :VIDE CA.E/A
A video camera ta&es continuous pictures and !enerates a di!italGanalo! si!nalsfor displa$ on a monitor or permanent recordin! A video camera captures ima!es
#$ #rea&in! down the ima!es into series of lines Each line is scanned one at a
time and continuousl$ var$in! intensities of redG!reen and #lue li!ht are filteredand converted into analo! si!nals These are then used to send picture over a
networ& throu!h computers
HHHHHHHHHHHHHHHHHHHHHHHHT?E END HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
http://en.wikipedia.org/wiki/File:Betacam_SP_camera.jpghttp://szwelldytech.en.made-in-china.com/product/WoAxDJcUalhd/China-PC-Camera-WD-W040-.html8/12/2019 Chap1.5 Input Devices
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