Chapter 2 - input and output devices

name 2 uses of keyboards

• input of data into application softwares

• typing in commands to the computer

advantages of keyboards

• fast entry of new text into a document

• easy to use

• easier to do verification checks as data is entered

disadvantages of keyboards

• difficult to use if user has limited arm or wrist use

• slow method compared to direct data entry

• uses up valuable desk space

uses of numeric keypad

• automatic teller machines

• typing in phone numbers

• point of sale terminals

• chip and PIN devices

• fast entry of numeric data into spreadsheets

advantages of numeric keypads

• faster than standard keyboards

• small easy to carry around

disadvantages of numeric keypads

• small keys makes it difficult to input data

• the order of numbers on keypad is not intuitive

uses of mouse

• opening, closing, minimising software

• grouping, moving, deleting files

• image editing

• control selection from a menu or selecting an icon

• scrolling up and down

advantages of mouse

• faster method of choosing an option compared to using a keyboard

• very quick way to navigate through applications and the internet

• does not take up large desk areas

disadvantage of mouse

• difficult to use if user has limited arm/wrist use

• easy to damage, can be clogged up with dirt

• difficult to use if there is no flat surfaces

uses of touchpad

• opening, closing, minimising software

• grouping, moving, deleting files

• image editing

• control selection from a menu or selecting an icon

• scrolling up and down

advantages of touchpad

• faster method of choosing an option compared to using a keyboard

• very quick way to navigate through applications and the internet

• does not take up large desk areas

• no need for a separate mouse, big advantage if there is no flat surfaces

disadvantage of touchpad

• difficult to use if user has limited arm/wrist use

• difficult to control pointer

• difficult to do functions like drag and drop

uses of trackerball

• alternative for people with RSI

• industrial control room environment to navigate through process screens

• select functions in luxury cars

advantages of trackerball

• no need fine control

• easier to use than mouse for people with limited arm/wrist use

• more accurate positioning on screen

• more robust

• need less desk space

disadvantages of trackerball

• not supplied with computer so it would be more expensive

• not a standard equipment so user may need training

uses of remote control

• alter functions for:

  • TV

  • satellite systems

  • DVD/Blue-ray players

  • Hi-Fi systems

• control multi-media systems

• control processes in industrial applications

advantages of remote control

can be operated from a reasonable distance

disadvantages of remote control

• difficult to use if operator has limited hand/wrist movement

• easy to block signal

uses of joystick

• gaming

• simulators to mimic actual controls

advantages of joystick

• easier to navigate the screen

• control is more realistic for some applications

disadvantages of joystick

more difficult to control the on-screen pointer

uses of driving wheel

• gaming

• simulators to mimic actual controls

advantages of driving wheel

• easier to control steering movements, more natural

• more realistic ‘driving experience’

disadvantage of driving wheel

• quite expensive

• movements can be too sensitive

uses of touch screens

• self-service tills

• choosing options on automatic teller machines

• public transport systems

• mobile phones, tablets, satellite navigation systems

• interactive whiteboard

• computer-based training where answers are selected during on-screen testing

• used as output device because they work as a flat-screen monitor

advantages of touchscreens

• faster entry of options

• very easy

• no training needed to use it

• can expand size of display

disadvantages of touch screens

• limited number of input options available

• can lead to health problems if operator has to use the system frequently

• screen can get very dirty

uses of scanners

• scan in documents and convert into a format for use in various software packages

• scan in old documents, protecting the orignials, as well as producing records in case the paper copies are lost or destroyed

• scan in photographs

• scan in barcodes at POS terminals

advantages of scanners

• images can be stored for editing at a later date

• when used with OCR, much faster and more accurate than typing in documents again

• it is possible to recover damaged documents and photographs by scanning in and then using appropriate software to produce an acceptable copy

disadvantages of scanners

• limited quality depending on how good a resolution the scanner is capable of

• they can be fairly slow at scanning, especially if the colour scanning mode is chosen or if the chosen scanning resolution is high

uses of digital cameras

• taking photos

• data-capture device

• take photos of patient’s teeth in dentistry

• creation of virtual reality tours around buildings

advantages of digital cameras

• easier to produce high quality photos compared to traditional cameras

• easier and faster to upload photos to a computer

• no need for film nor printing out photographs

• memory cards can store many photos

disadvantages of digital cameras

• need to be computer literate to know how cameras work

• some artistry lost because some softwares correct errors in the photographs

• need to compress images to reduce the amount of memory used

uses of microphones

• input audios

• input in voice-recognition software

• used as a sensor to pick up sounds

• used in video-conferencing or voice over internet protocol

advantages of microphones

• its faster to read the text than to type it out using a keyboard

• can manipulate sound in real time using special software rather than work on a recording done at some earlier stage

• if used in a voice activation system, it has the advantage of improving safety

disadvantages of microphones

• sound files can use up a lot of computer memory

• voice-recognition software is not as accurate as typing in manually

what is a sensor

a device that inputs data to a computer, to input the data into the computer, an ADC is used

uses of temperature sensor

• central heating systems

• automatic washing machines

• automatic glasshouses

• ovens

uses of pressure sensor

• intruder alarm systems

• washing machines

• robotics

• environmental monitoring

uses of light sensor

• automatic glasshouses

• automatic doors

• intruder alarm systems

• street lighting control

uses of sound sensor

• intruder alarm systems

• monitoring liquid and powder flow in pipes

uses of humidity sensor

• automatic glasshouses

• environmental monitoring

• factories where moisture levels are crucial

uses of pH sensor

• automatic glasshoueses

• chemical processes

• environmental monitoring

advantages of sensors

• more accurate readings taken

• continuous readings are taken

• any necessary actions will be initiated immediately since readings are taken continuously

• no need for human intervention, systems can be automatic

disadvantages of sensors

• sensors can be faulty → inaccuracy in results

• require ADC

uses of light pens

• selecting objects on CRT screens

• drawing on screens

advantages of light pens

• greater accuracy than touch screens

• small

• easy to use

disadvantages of light pens

• might lag when drawing on screen

• only works with CRT screens at the moment

• dated technology

what are direct data entry devices used for

used to input data into a computer without the need for much human intervention

uses of magnetic stripe readers

• on credit cards

• security devices to allow entry to buildings, hotel rooms

advantages of magnetic stripe readers

• fast data entry

• error-free

• secure

• prevents access to restricted areas

• not affected by oil/water/moisture etc

• no moving parts, very robust

disadvantages of magnetic stripe readers

• data is lost if magnetic stripe is damaged

• does not work at a distance

• information is not human readable

advantages of contactless debit card readers

• faster transactions

• 128-bit encryption protects data

• no need to worry about typing errors

• retailers will not have access to the customer’s credit card

disadvantages of contactless debit card readers

• more expensive than normal debit cards

• transactions are limited to a small maximum value

• people around you with proper reader can scan the card

uses of chip and PIN readers

payment purposes

advantages of chip and PIN readers

• more secure system than contactless payment

• more robust system than magnetic stripe cards

disadvantage of chip and PIN readers

need to ensure PIN is not read by somebody else while typing it in

uses of radio frequency identification readers

• livestock tracking (identify the location of every animal in farm)

• retail (track location of items)

• admission passes (no need to scan cards before getting on rides, can track people in theme park)

• Libraries

advantages of radio frequency identification readers

• tags can be read from a distance

• very robust and reliable

• fast read-rate

• bidirectional data transfer (can read or write data)

• bulk detection is possible (can detect several RFID tags at the same time)

disadvantages of radio frequency identification readers

• tag collision (signals of cards interfering with one another)

• easy to interrupt because RFID uses radio waves

• easy to hack into data transmitted by tag

• more expensive

uses of optical mark reader

read questionnaires / MC exam papers / voting papers where responses are registered in the form of lines / shaded areas

advantages of optical mark reader

• fast way to input results of a survey

• more accurate than keying in data because no need to type

• more accurate than OCR methods

disadvantages of optical mark reader

• needs to ensure marks are correctly positioned to gather accurate information

• sometimes have to manually check if marks are correctly filled in → time consuming + expensive

uses of optical character reader

• processing passports and identity cards

• convert hard copy documents into electric format

• used in automatic number plate recognition systems in car parks

• digitising historic books for researchers to use without damaging the originals

advantages of optical character reader

• faster data entry system than typing int data

• which reduces chances of error

disadvantages of optical character reader

• system cannot read some handwriting

• not a very accurate technique

extent of response, compare between OCR and OMR

OCR - can extend response

OMR - cannot extend response

prone to error, OCR vs OMR

OCR more lkely to cause errors

functions of OCR and OMR

OCR: convert hard copy docs into electric format

OMR: reads position of mark

simplicity of systems, OCR vs OMR

OCR: complex recognition needed

OMR: complex forms needed, simple recognition systems needed

instructions needed for OCR and OMR

OCR - less needed

OMR - more needed

uses of barcode readers

• supermarkets or shops, goods are marked with barcode → for stock control, itemised billing

• libraries → keep track of books in loan

• companies → electrical equipment is checked regularly

advantages of barcode readers

• much faster method of data entry

• less prone to mistakes

• automatic stock control

• tried and trusted technology

disadvantages of barcode readers

• expensive

• not fool-proof (barcodes can be swapped around items)

• easily damaged compared to RFID tags or magnetic stripes

uses of quick response code scanners

• advertising, code contains data about business address / number etc

• link to apps

• wi-fi authentication

• deliver argumented reality experiences

• establish virtual online stores

advantages of quick response code scanners

• can hold more information than barcodes

• its large storage system allows error-checking systems to be built-in → less prone to error

• easy to read, only need camera to read

• can transmit code as text message or image

• possible to encrypt QR codes

disadvantages of quick response code scanners

more than one QR format is possible → not all devices can identify all different formats

uses of CRT monitors

specialist areas like computer-aided design

advantages of CRT monitors

• screen can be clearly seen at a wider range of viewing angles than with most LCD monitors

• allow use of light pens in Computer-aided design / computer-aided manufacturing

disadvantages of CRT monitors

• weight hazard, cover large areas on desk

• can run very hot → fire hazard

• consume more power than LCD monitors

• can flicker → eyesight problems with prolonged use

uses of LED screens

• main output device in computers

• many offer touch-screen input

advantages of LED screens

• efficient / low power consumption

• lightweight

• do not suffer from screen image burn-in ( permanent image burned into screen over long periods of time) unlike CRT monitors

• large variations in screen sizes

• no flickering image

• sharp image resolution

• produce low electromagnetic fields compared to CRT monitors

disadvantages of CRT monitors

• inconsistent colour and contrast from viewing different angles

• motion blur

• lower contrast produced compared to CRT

• weak pixels that are improperly connected to adjoining pixels

• panel may not be uniformly illuminated by the back light → uneven intensity and shading over screen

uses of multimedia projector

• training presentations

• advertising presentations

• home cinema systems

advantages of multimedia projector

• allows many people to see presentation

• no need for several networked computers (no need for everyone to log on to their computers to watch a video)

disadvantages of multimedia projector

• fuzzy images

• expensive

• difficult to set up projectors

uses of laser printer

• when low noise needed

• when high quality and volume of printing needed

advantages of laser printer

• fast

• can handle large printing jobs

• consistently high quality

• toner cartridges last for long time

disadvantages of laser printer

• only really fast if several copies are being made

• colour laser printers are expensive to run

• produce ozone + volatile organic compounds → health hazards

uses of inkjet printer

• used when low-output volume is needed

• used when high quality images are needed

• 3D ones are used to produce prototypes in industries

advantages of inkjet printer

• cheaper than laser printer

• high quality

• lightweight = small physical footprint

• no ozone / volatile organic compounds produced

disadvantages of inkjet printer

• slow output when high volume needed

• cannot do large print jobs because ink cartridge run out quickly

• printing can smudge

• can be expensive if used frequently

uses of dot matrix printer

• used in noisy / dirty environment

• used in till receipts

advantages of dot matrix printer

• can be used in dirty or environments

• can produce carbon copies / multi-part outputs

• very cheap to run and maintain

• easy to use if continuous stationery is required

disadvantages of dot matrix printer

• very noisy

• costs more to buy compared to inkjet printer

• poor quality printing, slow

uses of plotters

• Architectural drawings

• engineering drawings

• animation characters

advantages of plotters

• high quality

• can produce large number of drawings accurately

• can print on different materials

disadvantages of plotters

• slow when printing

• expensive to buy

• large physical footprint

uses of 3D printer

• prosthetic limbs

• making items for reconstructive surgery

• making lightweight wings and aeroplanes in aerospace industries

• fashion and art

• parts of items no longer in production

advantages of 3D printer

• easier to manufacture items

• allows customisation of products

• faster to manufacture items, allows rapid prototyping

• cheaper when compared to labour and other costs involved in traditional ways of manufacture

• medical benefits

• can manufacture parts for machinery that are no longer made