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Computers, part of your life
Grade 11
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Input and output
Module 1.2
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 Input
Content
 Output
 Interactive whiteboards
 Input and output for physically
challenged users
 Input and output and health issues
 Test and improve
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Input
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Input ...
• provides running software with
instructions on what to do next
• can be data that must be processed
Data that is input may need to be used
immediately – or may be stored for
processing later
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Image capture
Picture data has become increasingly
important in the way we use computers
Digital cameras
• smartphone cameras
• digital (compact)
cameras
• DSLR (digital singlelens reflex) cameras
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Digital cameras (1)
Advantages
• Allows you to take many photos
• See the images immediately
• Easily transfer images to computer
(because already in digital format)
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Digital cameras (2)
Specifications that determine quality
Lenses
Sensor size
Optical zoom
Digital zoom
Resolution
ISO Rating
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Scanners
Input device that
scans images to a
computer –
bar codes, photos,
documents, 3D objects
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Software allows you to
specify resolution
DPI (dots per inch)
The greater the DPI,
the better the image
quality
The higher the DPI the
larger the resulting
image file
Colour depth
Resolution
Image quality of scanners
determined by
Number of different
colours that can be
represented by a pixel
24 bit colour (about
16.7 million different
colours) high enough
for practical purposes
The higher the colour
depth, the larger the
resulting image file
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Advantages of scanners (1)
 Large documents can be scanned into
single digital file
 Electronic copies stored digitally
 Scanned copies can be e-mailed directly
 OCR software used on documents
containing text scanned as images, to
convert images into editable documents
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Advantages of scanners (2)
 Old documents can be scanned and
stored
 Barcode scanners – libraries and Point
of Sale (POS) systems
 QR codes – connect to websites quickly
 Number plates of cars can be scanned
and recorded on e-toll roads
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Disadvantages of scanners
 Can take a lot of time –
depends on type of scanner and its
purpose
 Quality of digital image depends largely
on quality of the original hardcopy
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Biometric input (1)
• Capturing unique biological features of
a person
• Scanners ‘read’ and recognise any
part of you that is biologically unique
(e.g. fingerprint / iris / voice) – for
identification purposes
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Biometric input (2)
• Fingerprint scanners on smartphones,
laptops, flash drives, etc.
• Used instead of passwords, e.g. for
access control in buildings
• Mainly for security reasons
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Advantages of biometric input
 Main advantage is security
 Defeating biometric security is
difficult – tied to a single person
 Only the authorised person gets
access
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Disadvantages / limitations
of biometric input
 Expensive to implement, maintain
and use
 Needs additional hardware and
software (if not included in device)
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Input at ATMs
Gets input from
user (PIN, menu
choices, etc.)
Other input through:
• Card reader
• Modem / network
connection
• Touch screen
• Money counter
• Money deposit slot
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Advantages of ATMs
 Banking transactions at
any time of day or night
 You are not limited to
your own bank or country
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Disadvantages /
limitations of ATMs
 Can be dangerous to use an ATM
(have cash – prey to criminals)
 Skimmer installed over ATM’s card
reader – add a camera – capture
card details and PIN – pretend to ‘be
you’ – steal your money
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Input into POS systems
Barcodes and RFID (Radio
Frequency Identification) tags
• Used to automatically ‘recognise’
a product or item
• Barcode scanners scan the
barcode
• RFID tags store data on the tag or
card – detected wirelessly
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Input into POS systems
Barcodes and RFID tags
achieve two main goals
• Faster processing at pay points
• Better stock control
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Barcodes and RFID tags –
How does this work?
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Advantages of POS systems
 Faster than typing in prices on a
keyboard
 Prices updated and entered more
accurately
 Record how many items are sold and
track how much stock is left
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Disadvantages / limitations
of POS systems
 When system offline – difficult to
function
 Expensive equipment and software
required
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Some smartphones have an
additional radio technology
built into them called NFC
(Near Field Communication).
NFC is a standard or
technology that allows
electronic devices to connect
wirelessly and exchange
data, simply by touching
them together or bringing
them close together. NFC is
mainly used for payment
processing.
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Touch screens (as input devices)
• Combination of a LCD and
a thin ‘touch sensing’ film
• Pen tablet computers use a
high resolution pen / stylus
that communicates with the
screen wirelessly
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Advantages of Touch screens
 Allows more screen space in device
 Type of ‘immediacy’ in directly touching
the data or controlling components
 Intuitive – very little training needed
 Allows natural input – drawing and
gestures
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Disadvantages of Touch screens
 Not as fast or easy as using a physical
keyboard
 Can become dirty / oily / smudged
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Data collection devices
• Meter readers to capture water
readings
• Monitor patient’s temperature, heart
rate, blood pressure
• Weather buoys in oceans collect
data on weather conditions
• Monitor temperature, pressure and
humidity in controlled environments
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Advantages of data
collection devices
 Data captured automatically using
sensors, without human intervention
 Data captured more accurately than by
using human input
 Data captured faster than by using
human input
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Disadvantages / limitations
of data collection devices
 Sensors can fail, resulting in incorrect
data
 Only sensor-detectable data can be
collected
 Devices can be difficult and expensive
to update, repair or replace
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Input into smartphones and consumer
tablets
Touch screen
Hardware buttons
Camera / video camera
Accelerometer
Microphone
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Alternative keyboards
• Virtual keyboards – popping up an
image of a keyboard on the screen
• Project a virtual keyboard onto a
surface using laser or LED lights
• Wireless technology uses radio
waves to connect input devices to
computer device
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Activity 1
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Output
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Purpose of output is to…
• provide user with feedback in their
interaction with a computing device
• provide user with a more permanent
(non-electronic) copy of the results of
processing
• allow transmission of data between
computers / electronic devices
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Types of output
Visual output
• soft copy – on a screen
• hard copy – printed onto paper
Sound output
• speakers or headphones
Touch output
• joysticks and controllers vibrate / resist the user
• mobile devices vibrate
• 3D printers create physical copies of objects
Other output
• not designed for humans
• e.g. electrical signals to control equipment
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Display devices
• Display options that allow the user
to make choices / interact with the
program and operating system
• Display the results of processing
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Advantages of display devices
 Provide immediate feedback
 Allow for interaction between user
and computer
 Display content easily changed and
updated
 Text can be enlarged for the visually
impaired / high contrast used
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Disadvantages of display devices (1)
 Output is not permanent
 Output is difficult to share (unless it is a
data projector)
 Can lead to eyestrain / headaches
 Work not private (visible to passers-by)
 Expensive to replace
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Disadvantages of display devices (2)
 Consumes the most electricity
 Difficult to read in very bright light
 Quality is related to size – larger size
is usually of better quality
 Larger size is more difficult to
transport (and uses more power)
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Display devices – key specifications
Screen size
Resolution
Contrast ratio
Aspect ratio
Response time
Lumens for projectors
DMI and HDMI
Range of height and swivel adjustment
Viewing angle
Built-in USB ports / webcam / speakers
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Printers (1)
Specifications include
Speed
Resolution
Monthly duty
cycle
Number of
colours
Paper
options
Connections
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Printers (2)
Laser printers
• more reliable (e.g. don’t
have ink that can dry out)
• easier to maintain than
inkjet printers
• better for black and white
and general colour
• generally cheaper to run
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Printers (3)
Inkjets
– better for photo quality prints
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3D Printers
Allow you to create physical, threedimensional objects using CAD /
3D modeling software
Filament
A spool of plastic wire
(called filament) provides
the printing material
Print Head
Melts the filament
Build
Plate
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Wireless technology in output devices
Wireless technologies (WiFi, Bluetooth and
NFC) are used to increase flexibility and
usefulness of output devices
Wireless printing
Sound without
wires
Wireless video
and images
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Interactive
whiteboards
Example of how input
and output devices can
be combined
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Advantages of interactive
whiteboards
 Computer functions can be manipulated
on the board
 Better interaction and participation
 Notes made on whiteboard can be
saved and accessed
 Presenting content in multimedia format
facilitates different learning styles
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Disadvantages / limitations of
interactive whiteboards
 Needs dimly lit venue
 Small boards are difficult to read
 Do not use normal whiteboard markers
 Suitable software not always available
 Not affordable for many schools
 Repairs can be expensive
 Teachers sometimes hesitant of using
newer technology
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What makes it all work?
Drivers
• Software that allows a computer
to communicate with hardware or
devices and control them
• Operating systems have a large
collection of standard drivers
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Plug and Play
• O/S automatically detects and
configures a device, so it can be
used almost immediately
• Computer checks if it has the driver
to control it (and if not, it will ask you
to install it)
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Input and output
for physically
challenged users
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Visually impaired / Blind
• Braille keyboard and
Braille display device
• Magnification devices
• Large-key keyboards
• Braille printers
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Hearing impaired / Deaf
• On screen notices / flashing screen
instead of sound
• Vibration devices
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Motor control
• Eye tracking devices
• Head movement devices
• Large-key keyboards
• Large trackballs
• Joysticks
• Foot pedal control devices
• Sip and puff devices
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Input and output
and health
issues
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The way we sit and the way we use input
devices – sore neck, backache,
headaches, RSI
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Manage your work style
• Move around every hour or so
• Do not stare at screen for too long
• Use keyboard shortcuts
• Do exercises to relieve tension in joints
• Do not turn up volume of headphones
to drown out surrounding sound
• Adjust monitor settings and position, so
as not to hurt your eyes
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Activity 2
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Test and improve
Use the summary for own revision
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Written module activity