Gebruik om data in rekenaar in te voer
Twee hoof soorte:
• manual
• automatic
MEGANIES
MUIS
Oud (balletjie)
Nadele:
•Balletjie verloor
•Word vuil – haak vas
•Nie baie akkuraat
OPTIES
Koord
Koordloos
LED of laser – bespeur beweging relatief tot oppvl
Blink oppvl werk nie
Bluetooth
Infrarooi
Voordele:
•Geen kabels in pad
•Meer beweging
•Verder van rekenaar
Nadele:
•Batterye
•Duurder
•Sein verloor
•Makliker gesteel
SLEUTELBORD
SOORTE:
Ergonomies – voorkom RSI
Speletjies – spesiaal aangepas
QWERTY– eerste 6 sleutels spel
•Pyltjies
•Numeries
•Funksies
•Opdragte
•Konsep:
•Plat
•Raamwerk van geprogrammeerde sleutels
•Papier bo-oor met prente/woorde
•Kinders, restaurante
SCANNER
FLATBED
Skandeerders werk deur die skyn van 'n ligstraal op die oppervlak van die voorwerp wat jy skandeer.
Hierdie lig word dan weerspieël terug op 'n sensor wat die kleur van die lig bepaal. Dit word dan
gebruik om die digitale beeld op te bou.
Items wat geskandeer word, word gewoonlik gestoor in 'n foto-formaat.
Dit kan ook gebruik word om teks op papier te omskep in 'n digitale formaat wat deur die rekenaar
gebruik word. Spesiale sagteware - Optical Character Recognition - kan gebruik word om teks om te
sodat dit met 'n woordverwerker geredigeer kan word. As die oorspronklike teks nie van ‘n goeie
gehalte is nie kan jy opeindig met baie foute.
HANDHELD SCANNERS
is gewoonlik net 'n paar sentimeter breed en word in die hand gehou terwyl hulle oor die dokument te
gerol word. Die beelde wat geproduseer word, is oor die algemeen nie so hoë gehalte as die wat
geskandeer is met 'n flatbed scanner nie.
Voordele
Akkuraat en redelik hoë kwaliteit
Beelde kan verbeter word met 'n grafiese program
Nadele
Beelde kan baie geheue spasie opneem
Beelde kan kwaliteit verloor in die skandering en digitalisering proses
Die gehalte van die finale beeld is afhanklik van die kwaliteit van die oorspronklike beeld
MIKROFOON
Word gebruik om klank in te voer.
Die klank word waargeneem deur die
mikrofoon en 'n elektriese sein word na die
rekenaar gestuur.
Spesiale hardeware omskep analoog data in
digitale data.
Spraakherkenning stelsels - laat die gebruiker
teks inlees en dan omskep die rekenaar dit in
teks.
Diktering kan baie vinniger wees as tik, maar
die sagteware is nie volmaak nie en woorde
kan verkeerd geinterpreteer word.
WebCam
‘n Real-time kamera is (gewoonlik,
maar nie altyd 'n video kamera nie)
wat se beelde kan verkry word deur
die internet.
Digitale kamera
•Neem foto's elektronies en stoor in digitale formaat.
• word op 'n geheue kaart gestoor
•Foto’s kan afgelaai word van die geheue kaart op 'n
rekenaar en dan gedruk, geberg of gemanipuleer word
met 'n foto redigering program.
•Nie tevrede met foto – vee dadelik uit
kwaliteit hang af van die resolusie of die aantal pixels wissel van 4 - 12 megapixels (miljoene pixels in die
beeld)
•meer pixels - beter gehalte
•Kan dikwels ook kort video clips met klank neem.
•SD-kaart (Secure Digital)
drie verskillende groottes: die oorspronklike grootte, die
"mini" grootte, en die "mikro" grootte.
Digitale kamera
Voordele
Geen film, geen ontwikkeling
Beelde kan onmiddellik gesien en ongewenste beelde geskrap word
Beelde kan geredigeer word, vergroot of verbeter word
Ekstra of groter geheue kaarte kan gekoop word
Nadele
Duurder as gewone kameras
As die geheue vol is, moet die beelde afgelaai word na 'n rekenaar
GRAPHICS TABLET
Gebruik deur grafiese ontwerpers en illustreerders.
meer akkurate sketse op skerm as met muis.
akkuraat tot binne honderdstes van 'n duim.
plat tablet waarop jy teken met 'n spesiale pen.
As jy teken op die tablet , vertoon die beeld op die skerm.
Voordele
Meer natuurlik om met 'n stylus te teken
‘n Groter vlak van akkuraatheid kan bereik word
Nadele
Nie geskik vir algemene werk soos wys en klik op die menu-items
Baie duurder as 'n muis
RAAKBLAD
invoer toestel gewoonlik op 'n skootrekenaar.
gebruik word i.p.v. ‘n muis.
Deur jou vinger oor die oppervlak te beweeg tel sensors die rigting en spoed van die
beweging op. Die sensors reageer net op 'n vinger en nie 'n potlood of ander
voorwerp. Daar is gewoonlik twee knoppies langs die touchpad wat gebruik word om
die linker en regter muis knoppie te vervang.
Voordele
Nuttig vir skootrekenaars i.p.v. muis
Kort vinger bewegings is al wat nodig is
Nadele
oefening en vaardigheid
Klam, sweterige vingers kan die seine ontwrig
JOYSTICK
Beweeg in baie rigtings en die rekenaar weet na watter rigting dit verskuif
knoppies se posisie kan deur die rekenaar gelees word.
ook gebruik vir beheer van masjiene soos hyskrane, vragmotors en rolstoele.
Voordele
beter speletjie ervaring
Nadele
Sommige mense vind joysticks moeilik om te beheer as 'n muis.
nie besonder sterk en kan maklik breek
TOUCH SCREEN
werk as beide 'n toevoer en 'n afvoertoestel.
Raak met vinger aan opsies op die skerm.
Werk goed met 'n menu-gedrewe koppelvlak - 'n OTM
maklik om te gebruik en dikwels in openbare plekke
Voordele
Maklik om te gebruik - intuïtief, nie opleiding nodig
Geen ekstra randapparatuur soos 'n muis
Sagteware kan die skerm verander terwyl dit gebruik word
Nadele
Nie geskik is vir invoer van groot hoeveelhede data
Nie baie akkuraat vir detail nie
Vermoeiend om te gebruik vir 'n lang periodes
Duurder as alternatiewe soos 'n muis
Nie robuust - kan gou foutief raak as misbruik.
MAGNETIC INK CHARACTER RECOGNITION
banks use a technique called 'Magnetic Ink Character
Recognition' (MICR) which enables them to process 300
cheques per minute with 100% accuracy.
At the bottom of each cheque are a series of numbers
which record: the cheque number, the bank code, the
customer's account number
These numbers are written in a special ink which contains
iron particles.
This ink is magnetised and commonly called
'magnetic ink'. It can be read by a special machine
called a Magnetic Ink Character reader (MICR).
OPTICAL MARK READER (OMR)
Have you ever looked closely at the National Lottery ticket selection form? Or have you ever had
to do a multiple choice test at school where you had to use a pencil to show your answer
These forms are scanned by a special piece of equipment called an 'Optical Mark Reader' (OMR).
they detect the presence of your pencil mark by reflecting light onto it. Less light is reflected
where a mark has been made.
The OMR then interprets the pattern of marks and sends the results to the computer for storage,
analysis and reporting.
Advantages
A fast method of inputting large amounts of data
Only one computer needed to collect and process the data
OMR is much more accurate than data being keyed in by a person
Disadvantages
If the marks don't fill the space completely, or aren't in a dark enough pencil, they may not be
read correctly
Only suitable for recording one out of a selection of answers, not suitable for text input
The OMR reader needs the answers to be on the prepared forms which will all be identical to
one another.
OPTICAL CHARACTER RECOGNITION (OCR)
An OCR system consists of a normal scanner and some special software. The scanner is used to scan text on a
document or piece of paper into the computer. The OCR software then examines the page and changes the
letters into a form that can be edited or processed by a normal word processing package.
The ability to scan the characters accurately depends on how clear the writing is.
Scanners have been improved to be able to read different styles and sizes of text as well as neat handwriting.
Although they are often up to 95% accurate, any text scanned with OCR needs careful checking because some
letters can be misread.
OCR is used to automatically recognise postcodes on letters at sorting offices.
Advantages
•Cheaper than paying someone to manually enter
large amounts of text
•Much faster than someone manually entering large
amounts of text
•The latest software can recreate tables and the
original layout
Disadvantages
•Not 100% accurate, there are likely to be some mistakes made during the process
•All documents need to be checked over carefully and then manually corrected
•If the original document is of poor quality or the handwriting difficult to read, more mistakes will occur
•Not worth doing for small amounts of text
BARCODE READER
An input device that converts a pattern of printed bars into a number that a computer can read.
They are often used by businesses to quickly input price and product information.
Most items that are for sale in shops have a barcode printed somewhere on
the packaging. The barcode is a series of vertical bars of varying widths that
give information about:
the country of manufacture
the name of the manufacturer
a product code
The barcode does NOT contain the price of the item - this is held on the company database.
A barcode reader is an automatic input device which is used to scan or 'read' the barcode by
using a visible red light. The reflected light is translated into digital data that is interpreted by the
computer to identify the product and price from the database.
The main advantage of using a barcode system is that any price change only needs to be made to
the database and not every single product package.
Barcodes are also used on books to show the book's ISBN number - have a look at any textbook
that you have in your bag. They are also used on library tickets so that when your ticket is
MAGNETIC STRIP READER
Magnetic strips are usually found of the back of most credit cards, cheque guarantee cards,
loyalty cards, membership cards etc.
The magnetic strip can hold personal details about the card number such as account number and
name. The strip can contain up to 60 characters, stored magnetically.
To read the data on the card, it is 'swiped' through a Magnetic Stripe Reader machine and the
data is read and fed back to the computer.
Advantages
Simple to use
Cheap to produce
Data can be altered if necessary
Security has been improved by the use of PIN numbers which must be entered into a machine to
confirm that you are the rightful card owner
Disadvantages
Very limited storage capacity for data
Data can be easily destroyed by strong magnetic fields
Not always secure as thieves can obtain the readers and read the data on the card.
BIOMETRIC DEVICES
There is an increasing trend towards using biometric data from people
in order to identify them. Finger print and retinal identification are
being used in many places now and even facial recognition systems are
starting to be introduced.
Special devices are needed to capture the biometric data which is then
passed onto the computer for processing and identification.
Biometric authentification methods can be used to identify you at
ATMs to withdraw cash, in computer networks to allow you to log on
and many schools are now introducing 'fingerprint registration'!
SENSORS
Sensors are used to detect physical quantities outside
a computer such as light, temperature and pressure.
They collect data automatically and usually at regular
intervals. This data can either be transmitted
immediately to the computer or it can be stored for a
period of time and a batch of readings sent in one go.
In order to process input from sensors, a device called
an 'Analogue to Digital Converter' (ADC) must be
connected between the computer and the sensor.
This device converts the analogue signals from the
sensors to digital data that the computer can process.
RFID (Radio Frequency Identification)
use of a wireless non-contact radio system to transfer data from a tag attached to an object, for the
purposes of automatic identification and tracking.
The tag contains electronically stored information which can be read from up to several metres (yards)
away.
Unlike a bar code, the tag does not need to be within line of sight of the reader and may be embedded
in the tracked object.
can be used to bill motorists for access to toll roads or parking.
Contain an integrated circuit for storing and processing information, modulating and demodulating a
radio-frequency (RF) signal, collecting DC power from the incident reader signal, and other
specialized functions; and an antenna for receiving and transmitting the signal.
A sheep with an ear tag
FID tags used in libraries: square
book tag, round CD/DVD tag and
rectangular VHS tag.
RFID chip, next to a
grain of rice
An RFID tag used
for electronic toll
collection