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1. Input & Output
Devices

2. An input device captures data and sends it to a
computer system.
Input devices convert physical movement, such as
key pressing, or environmental data, such as
temperature, sound or light into electrical signals.
Input
Devices
There are two types of input device: manual and
automatic.

3. Manual Input
Devices
A manual input device requires a human hand to
control it…
Mous
e
Keyboar
d
Scanne
r
Camer
a

4. Manual Input
Devices
Tracker ball
Joystic
k
Graphics
tablet
A manual input device requires a human hand to
control it…

5. Manual Input
Devices
Keyboard
The most
common input
device
You press keys to
input data into the
computer
The most
common type of
keyboard is the
QWERTY
keyboard
People are familiar
with keyboards, so
they don’t need to
be trained
Skilled typists can
work very quickly
A lot of different
keyboards are
available, e.g.
ergonomic
They are very
reliable and cheap
Incorrect use or
over-use can cause
RSI
Many people
cannot type and
look at the screen
at the same time,
so typing can be
time consuming
Uses Advantages Disadvantages
Device

6. Manual Input
Devices
Concept
Keyboard
Simplified keyboard
used in fast food
restaurants and
other businesses,
where a waterproof
keyboard and
simplified choices
makes serving
customers much
quicker
Used on computer-
style toys for small
children
Very quick and
simple to use
Overlay can be
wiped clean easily
Overlay makes
the keyboard
waterproof, so
safer for food
restaurants
Have to change
the overlay sheet,
when the menu
changes
You would need to
increase the
number of keys to
increase the
number of options,
so not very flexible
Uses Advantages Disadvantages
Device

7. Manual Input
Devices
Graphics
Tablet
A graphics tablet
consists of a pad
and a special pen
It allows artists and
graphic designers
to draw naturally
as though they
were drawing
on paper
The image is
instantly converted
to digital data
User can get
much more
control, similar to
the natural way of
drawing
Advanced models
detect subtle
changes in
pressure, to
enable thicker
lines to be drawn
The user can
zoom in to an area
of the drawing for
higher accuracy
Large models are
very expensive
Need a large desk
area
Holding a pen for a
long time is more
tiring than holding
a mouse
Uses Advantages Disadvantages
Device

8. Manual Input
Devices
Mouse
Most common
pointing device
Used to point and
click on icons or
menus
Combines well
with a keyboard
Fast and accurate
Most people are
skilled at using a
mouse, so no
training is needed
Prolonged use can
lead to RSI
Need a flat surface
to use them
For an optical
mouse, the laser
does not work well
on all surfaces
Tracker ball
A tracker ball is
basically an
upside down ball
mouse.
The user runs their
thumb over the
ball to control the
on-screen pointer
User can get great
pointing accuracy,
without moving
the hand
Useful where desk
space is limited
Some people find
that the thumb
gets painful with
prolonged use
Ball can get
greasy and dirty
Uses Advantages Disadvantages
Device

9. Manual Input
Devices
Uses Advantages Disadvantages
Device
Scanner
Used to convert
printed images or
text into a file of
digital data
There are two
types: handheld
and flatbed
Even cheap
scanners produce
quality images
Any printed image
can be inserted
into a document
Images can be
edited before use
Pictures can use a
lot of memory
The quality of the
final image is
dependent on the
original image
Issues of copyright
protection
Joystick
Originally
designed for
pilots to control
aeroplanes
Used to control
wheelchairs and
for playing games
They give a more
realistic gaming
experience when
playing games
such as flight
simulators
Many different
types available
Some people find
them difficult to
operate, especially
in 3-d
environments

10. Manual Input
Devices
Digital
Camera
Used for taking
still images which
can be uploaded
to a computer for
permanent
storage
You can preview
the image before
pressing the
shutter button
No film needed or
development
costs
Unwanted images
can be deleted
When the drive is
full, images need
to be uploaded to
a computer or
deleted
High resolution
camera does not
guarantee good
images
Touchpad
or
Fingerpad
A pointing device,
built into a laptop
for convenience
Portable - built
into the laptop
Don’t need to
carry extra
equipment
around
Small movements
needed to move
the cursor
Takes practice to
master
Some people find
them very fiddly
Fingers need to be
clean and free of
grease
Uses Advantages Disadvantages
Device

11. Automatic Input
Devices
An automatic input device inputs data without the
need for human intervention (once the device has
been set up), e.g. MICR, OMR, barcode reader,
webcam, microphone, sensor.
Microphon
e
Webca
m
Barcode
reader

12. Automatic Input
Devices
MICR
Magnetic
Ink
Character
Recognition
Banks print
important data on
the bottom of
cheques using
magnetic ink
This ink is then
read by a computer
Very quick and
accurate
processing of data
– very low error
rate. Humans
could not achieve
the same accuracy
Very secure as any
attempt to
change the
numbers on a
cheque will be
ignored as the
reader only
recognises
magnetic ink in
the same font
Expensive to
produce and print
magnetic ink, and
the card reader is
also expensive
Banks are the
main user – very
few other
applications
Uses Advantages Disadvantages
Device

13. Automatic Input
Devices
OMR
Optical
Mark
Recognition
Used when you
mark the numbers
with a pencil on
a lottery ticket
Also used to mark
multiple choice
exam papers, and
paper-based school
registers
Very fast method
of reading data,
which reduces
queuing time for
lottery tickets
More accurate
than human
data entry
Sometimes
incomplete marks
are not read
correctly
Only pre-prepared
forms can be
scanned into the
computer
Uses Advantages Disadvantages
Device
OCR
Optical
Character
Recognition
Uses a scanner to
scan text, then
software converts
the text into a word
processor file
Used to read post
codes, as part of the
sorting process
Quicker than
typing in the text
Latest software
can recognise
tables and even
handwriting
Reduces the cost
of posting a letter
Sometimes it is
not very accurate
Documents need
to be proof-read
after scanning
Only worth doing
for large amounts
of text

14. Automatic Input
Devices
Barcode
Readers
Used to identify
products in shops
The code is read by
a barcode scanner
which identifies the
product name,
manufacturer and
country of origin
Very quick and
accurate way to
enter data – suits
busy shops
Prices changes
are made on the
database, not the
barcode – more
flexible system
All barcodes need
to be programmed
into the computer
in advance
The reader may
not be able to read
the barcode on
wrinkled
packaging
Uses Advantages Disadvantages
Device
Magnetic
Stripe
Reader
Found on the back
of bank cards and
store loyalty cards
The stripe holds
information, such
as the account
number and the PIN
Simple, cheap and
effective
The data on the
card can be
altered if needed
‘Chip n’ Pin’ has
increased security
Magnetic stripe
can get scratched
Not much data
can be stored
Thieves can read
data on cards
then use the cards
themselves

15. Uses Advantages Disadvantages
Device
Microphon
e
Used to input
sound into the
computer
Used to give the
computer
commands, or to
dictate letters
directly to a word
processor
Very cheap piece
of equipment
Helpful for people
with additional
needs or for busy
people who need
very quick letters
Computer can
misread voice
instructions due to
natural variations
in people’s voices
Generally, the
sound quality from
a PC microphone is
poor
Automatic Input
Devices
Webcam
Used to input
moving images
into the computer
for use in online
communication
Very cheap piece
of equipment
Enables people to
see each other
whilst they chat
The image quality
from most
webcams is poor
The moving
picture tends to
flicker due to
current limitations
in data transfer

16. Output
Devices

17. Output
Devices
An output device is used to display or use
information that comes out of a computer system.
Output devices convert electrical signals from a
computer system into…
Sound (speakers or headphones)
Images & Text (screen or printer)
Movement (actuator, electric motor)

18. Output
Devices
Monito
r
Speakers
Plotte
r
Headphone
s
Printe
r

19. Output
Devices
TFT
Monitor
Thin Film Transistor
monitors are more
commonly known
as flat screens or
LCD screens
Take up very little
space
Run very quietly
and produce little
heat
Use about a third
of the energy of
a CRT monitor
Easy to damage
Colour contrast on
cheaper models is
not as good as
CRT monitors
You may get
‘dead’ pixels
Uses Advantages Disadvantages
Device
CRT
Monitor
Cathode Ray Tube
is very old
technology.
Almost completely
replaced by flat
screen monitors
Robust and
difficult to
damage
Reliable
Last for a very
long time
Large, bulky and
unsightly
Can be heavy
Produce a lot of
heat
Old technology

20. Output
Devices
Speakers
&
Headphones
When connected
to a computer
through a sound
card, music can be
played
Gives feedback to
user during general
computer use
Can help blind
people use the
computer
A presentation
can be more
powerful with
sound
Games are a lot
more involving
and realistic
with sound
Speakers are not
useful in a network
room, as everyone
would disturb each
other
Headphones can
be uncomfortable
with extended use
Uses Advantages Disadvantages
Device
Plotter
These are specialist
printers that can
produce high
quality printouts
on large pieces
of paper
Very high quality
printouts
Almost any size
paper can be used
Slower than
normal printers
Expensive to
purchase and run

21. Printer
s
There are 3 main types of printer…
Dot
Matrix
Laser
Inkjet
Uses Advantages Disadvantages
Device
General purpose
use for family or
home office
Cheap to buy
Latest models
can be very fast
Ink cartridges can be
very expensive
Print quality not
always very good
Business use for
letters,
stationery and
images
Quality printing
Good for large
areas of colour
Quiet & Quick
More expensive to
buy than inkjets
Toner cartridges
are expensive
Business use
for duplicate
documents
Can make a
carbon copy
Can print on
continuous
rolls of paper
Noisy and rather old-
fashioned technology
Poor quality and only
prints in black ink