input output devices

• Keyboard:

  • Advantages:
  • Fast entry of new text into a document
  • Easy to use
  • Easy to verify
  • Disadvantages:
  • Can be difficult at times
  • Slow method of data entry
  • Uses valuable desk space
  • Used to input text, numbers and instructions into the computer
• Numeric keypads:

  • Advantages:
  • Faster than standard keyboard
  • Easy to carry around
  • Disadvantages:
  • Makes input difficult due to small numbers
  • Order of the numbers is not intuitive
  • Used to enter numbers only
  • Used in ATMs, POS terminals, Chip and PIN devices and entering data in a spreadsheet
• Mouse:

  • Advantages:
  • Fast
  • Quick to navigate
  • Does not require a large desk space
  • Disadvantages:
  • Difficult to use at times
  • Easy to damage
  • Works well with flat surface only
  • Pointing device
  • Recent developments include optical and cordless mouse
  • Used for making selection
• Touchpad:

  • Advantages:
  • Faster
  • Integrated device
  • Works without a flat surface
  • Disadvantages:
  • Can be difficult to use at times
  • Difficult to control the pointer
  • Difficult to handle while dragging and dropping
  • Used as pointing device in laptop computers
• Trackerball:

  • Advantages:
  • Does not need fine control
  • Easier to use than a mouse
  • Accurate position of the pointer
  • More robust
  • Needs less desk space
  • Disadvantages:
  • Not supplied as a standard computer device
  • User may need training
  • Used in applications where the user has a disability
  • Used in control room environment
  • Used in some luxury cars
• Remote Control:

  • Advantages:
  • Operates from a reasonable distance
  • Can select chemical processes from a distance
  • Disadvantages:
  • Difficult to use
  • Easier to block signals
  • Used to control the operation of devices using infrared signals
  • Used for Televisions, satellite systems, DVD players, multimedia systems and industrial applications
• Joysticks:

  • Advantages:
  • Easy to navigate the screen
  • More realistic control
  • Disadvantages:
  • Difficult to control
  • Used in simulation, video and computer games
• Driving wheel:

  • Advantages:
  • Easy to control steering movements
  • Experience closer to real life
  • Disadvantages:
  • Expensive
  • Movements can be extra sensitive
  • Feedback to the driving wheel is non-existent
  • Used in simulation, video and computer games
• Touchscreen:

  • Advantages:
  • Faster
  • Easy
  • User-friendly
  • Disadvantages:
  • Limited options
  • Leads to RSI
  • Responsiveness varies
  • Used in petrol stations, ATMs, POS terminals, airports, railway stations, tourist offices, satellite navigation systems, mobile phones, PDAs, interactive white boards and computer-based training
  • Used as an output device in some situations
• Scanner:

  • Advantages:
  • Images can be edited
  • Faster and accurate
  • Recover damaged photographs and documents
  • Disadvantages:
  • Limited quality
  • Slow
  • Used to enter hard copy information into the computer
  • Used to scan documents, photographs and barcodes
• Digital camera:

  • Advantages:
  • Produce better quality photographs
  • Easier and faster to upload
  • No need to develop film
  • Memory cards have a large storage space
  • Disadvantages:
  • Needs to be computer literate for using this device
  • Resolution still is not that good
  • Images are compressed
  • Stores the images in solid state memory
  • Can connect to the computer using USB port
  • Can use wireless data transfer
• Microphone:

  • Advantages:
  • Faster
  • Can manipulate sound in real time
  • Disadvantages:
  • Sound files take a lot of memory space
  • Voice recognition software is not accurate
  • Used to input speech and sounds
  • Can be used as sensor to pick up sound
  • Used in video conferencing
• Sensors:

  • Type of sensor:
  • Temperature
  • Pressure
  • Light
  • Sound
  • Humidity/moisture
  • PH
  • Water level
  • Applications:
  • Washing machines, central heating systems, glasshouses, ovens
  • Burglar alarm system, washing machines, robotics, environmental monitoring
  • Glasshouses, automatic doors, Burglar alarm systems, street lighting control
  • Burglar alarm systems, monitoring liquid and powder flow in pipes
  • Glasshouses, environmental monitoring, factories
• • Chemical processes, glasshouses, environmental monitoring
  • Weather stations, Dams, flood warning centers
  • Used to input measurement or physical quantities into the computer
  • Information from sensors need to be converted using ADC
  • Used in monitoring and control applications
• Graphic Tablet:

  • Advantages:
  • Modify drawings
  • Accurate drawings
  • Can record level of pressure
  • Disadvantages:
  • Expensive
  • Takes longer to draw
  • Not user-friendly
  • Can be damaged easily
  • A pointing device often used by designers and artists to allow natural hand movements to be input to graphics applications
• Webcam:

  • Advantages:
  • Instant operation
  • Easy communication
  • Disadvantages:
  • Limited features
  • Poor quality
  • A very basic video camera used to feed live video into a computer
• Light pen:

  • Advantages:
  • Accurate
  • Small
  • Easy-to-use
  • Disadvantages:
  • Lag when drawing
  • Works with CRT monitors only
  • Not accurate when drawing
  • Dated technology
  • Used as a pointing device or to ‘write’ on the screen of a computer
• Magnetic Strip Reader:

  • Advantages:
  • Fast
  • Error free
  • Secure
  • Robust
  • Not affected by oil, water, moisture etc.
  • Restricted access
  • Disadvantages:
  • Damage to magnetic strip results in data loss
  • Doesn't work at a distance
  • Data can be stored in the form of magnetized dots
  • Used on credit, debit, ATM and membership cards
• Contactless Card Reader:

  • Advantages:
  • Fast
  • Uses encryption
  • No typing errors
  • Secure
  • Disadvantages:
  • Expensive
  • Can be easily misused
  • Limited transactions
  • A contactless smart card is a contactless 13.56-MHz credential whose dimensions are credit-card size. Its embedded integrated circuits can store and sometimes process data and communicate with a terminal via radio waves
• Chip and PIN Reader:

  • Advantages:
  • Secure
  • Robust
  • Disadvantages:
  • Fraud
  • Similar to smart card readers
  • Used at EFTPOS
  • Device has a slot where card is placed and the chip is read
• Radio Frequency Identification Reader (RFID):

  • Advantages:
  • Can be read from a distance
  • Robust technology
  • Fast
  • Bidirectional data transfer
  • Bulk detection
  • Disadvantages:
  • Tag collision
  • Jam and interrupt
  • Easy to hack
  • Uses Radio waves to read and capture information from a Tag
  • Used in livestock tracking, retail, admission passes, libraries etc.
  • The RFID Tag is made up of two components: Microchip, Antenna
• Magnetic Ink Character Reader/Recognition (MICR):

  • Advantages:
  • Security
  • Error free
  • Magnetic ink characters are still read even if overwritten
  • Disadvantages:
  • Limited characters can be read
  • Expensive
  • Can read characters printed in a special ink
  • Used in banks to read cheques
  • Banks use batch processing to read the data from the cheques
• Optical Mark Reader/Recognition (OMR):

  • Advantages:
  • Fast
  • Automatic
  • Error free
  • More accurate than OCR
  • Disadvantages:
  • Forms need to be accurately designed
  • Can lead to problems if options are not correctly shaded
  • Can read marks written with a pen or pencil
  • Used to read questionnaires, MCQs, etc.
• Optical Character Reader/Recognition (OCR):

  • Advantages:
  • Fast
  • No errors
  • Disadvantages:
  • Difficult to read hand written documents
  • Not very accurate
• Barcode Reader:

  • Advantages:
  • Fast
  • Improves safety
  • Automatic stock control
  • Tried and trusted technology
  • Disadvantages:
  • Expensive to administer
  • Not foolproof
  • Easily damaged
  • Used to read information from a barcode
  • Used in supermarkets, libraries, etc.
• Quick Response Codes:

  • Advantages:
  • No need to write or key in
  • Effective method of advertising
  • Disadvantages:
  • Lack of familiarity of the QR codes
  • Dependability on a mobile device
  • A matrix filled in dark squares on a light background
  • Can hold over 7000 digits