The most common input device to enter text, numbers
and instructions into computers
Disadvantages
Users with limited arm/wrist
use find keyboards difficult to
use.
slow when compared to direct
data entry (e.g. optical mark
recognition)
takes up physical space
braille keyboard
The braille keyboard has raised dots to identify
the keys. This will help the blind people input
data into the computer.
concept keyboard
The concept keyboard uses icons or phrases instead
of standard letters. They are often used in fast food
restaurants, supermarkets, shops where a single
key represents an item.
Mouse
Uses
used for opening, closing and minimising software
used for grouping, moving and deleting files
very useful when editing images, for example
controlling the size and position of a drawing
to select icons
Advantages
enables rapid navigation through applications and the Internet
are small and so takes up little physical space
Disadvantages
people with restricted hand/wrist movement can have difficulty
difficult to use if there is no flat surface
Touchpads
Touchpads are used in laptop computers
as a pointing device.
Advantages
enables rapid
navigation through
applications and the
Internet
integrated into
the laptop, aids
portability
can be used
when when
there are no
flat surfaces
faster to select an option
compared to using a
keyboard
Disadvantages
people with restricted hand/wrist
movement can have difficulty
more difficult to use
when compared with a
mouse
can be more difficult to use
when doing certain
operations such as “drag and
drop”
Trackerballs
Uses
has the same
pointing/cursor
control capability
as a mouse
used in control room
environment where it
is faster and more
robust than a mouse
Advantages
easier for peope
with limited
hand/wrist
movement
since it is
stationary, it
takes up less
desk space
Disadvantages
more expensive since they are not a
standard equipment
Remote Control
Uses
commonly found
in home
entertaiment
devices
used in industrial
applications to remotely
control processes, stop
and start machinery, etc
Advantages
can be operated from a distance
some chemical processes are hazardous, so it is safer
to operate equipment from a distance
Disadvantages
people with restricted hand/wrist movement can have difficulty
signal between the control and device can be easily blocked
Joysticks
most popular input device for computer
games ,used in simulators (e.g. flight
simulators) to mimic actual controls
Advantages
easier to control game actions
can control game actions by varying the
pressure, speed and direction of the joystick
Touch Screens
User chooses an option
by touching the
button/icon on the
screen, without the need
for any pointing device.
Advantages
faster data entry of options
easier to choose options
a user-friendly method for keying in data
prevents people from keying in information which could
potentially corrupt the computer system
Disadvantages
limited number of options available
screen can get very dirty with constant touching
Uses
used where selections
are made on screen
used in PDAs mobile
phones and satellite
navigation systems
Magnetic stripe readers
The magnetic stripe found, for
example, on the back of a credit
card, debit card, ATM card contains
useful information such as the
account number, expiry date and
start date.
Advantages
faster data entry
error free since no typing is involved
Disadvantages
if the magnetic stripe gets damaged, the data is lost
since the information is
not human readable, this
can be a disadvantage in
some situations
Barcode readers
Uses
used in supermarkets and other
shops where the goods are
marked with a barcode; libraries
to scan library cards and books
Advantages
faster data entry and fewer mistakes
enables automatic stock control
when an item price is changed, only the central
database needs to be updated. There is no need to
change the prices individually on each item
Disadvantages
can be relatively expensive to administer
Optical Mark Recognition (OMR)
Uses
used to read questionnaires, multiple-choice questions, etc
where responses are in the form of shaded areas
Disadvantages
there can be problems if the
forms are not filled in correctly
Advantages
a very fast way of inputting the results of a test, survey, etc
more accurate than keying in the data since there is no typing
Optical Character Recognition (OcR)
Software that takes scanned text and converts it into a computer readable form.
Disadvantages
may not be accurate as system still has difficulty reading handwriting
Advantages
faster data entry
depending on the
source, number of
errors is reduced
since there is no
manual data entry
MAGNETIC Ink Character Recognition
(MICR)
Disadvantages
only certain characters can be read
Advantages
no manual input, thus errors are reduced
Read characters printed in a
special ink. For example, the
characters at the bottom of
a bank cheque.
Digital Cameras
Advantages
easier to produce better quality
photographs than with a traditional
camer
memory card can store several
hundred photographs
easier and faster to
upload photographs to a
computer
no need to develop film and print out photographs
easy to delete an image from memory
Disadvantages
some artistry lost since software now corrects errors in
the photographs (e.g. incorrect exposure, removal of red
eye, etc)
Webcams
Disadvantages
limited features and picture is often of poor quality
needs to be connected to the computer (not so with laptops, though)
Advantages
allows people too keep in contact with each other without travelling
Connected directly to the computer through a USB port and
they do not have a memory. Used to enable video
conferencing.
Microphones
Uses
used to input speech/sounds to be used in various applications (e.g. presentation, special effects)
used in voice recognition software (e.g. convert speech into text). This is useful for people with limited
hand/wrist movement.
Advantages
faster to read in text than to type it in using a keyboard
Disadvantages
sound files can use up
a lot of computer
memory
voice recognition software is not
as accurate as typing in
manually (e.g. cannot distinguish
between words that sound alike)
Sensors
A device which measures some physical quantity
which is continuously changing (e.g. temperate, light,
etc) and inputs it to a computer. Sensors are usually
used in monitoring and control applications.
Disadvantages
faulty sensors can give false results
Advantages
readings ar continuous, so there is no break in the monitoring
readings are
generally more
accurate than
readings taken
by human
operators
Graphics Tablets
Used with a stylus to produce freehand
drawings. The images produced can then
be stored in a file on a computer.
Advantages
an accurate method of drawing compard with using a mouse or
a trackerball
Disadvantages
more expensive than other pointing devices, such as a mouse
Light Pens
Light-sensitive pen-like device that contain
sensors that send signals to a computer
whenever light changes are detected. It is
placed against monitor when used and
used commonly to edit digital images.
Advantages
easy to use
Disadvantages
problems with lag when drawing on screen
only work with CRT (cathode ray
tube) monitors at the moment
Output devices
Monitor
Printers
Laser printers
best for fast high quality
high volumne printing
Plotters
can produce highly accurate,
very large drawings (blueprints
of buildings) and posters
Inkjet printers
printing may “smudge”
Dot matrix printers
an impact printer, alow, noisy and output is not good quality
can produce carbon-copies
Braille printer
produce raised dots
printouts to help blind
people read output
from computer
Speakers
can help blind/partially sighted
people through audio output of text
used to output sound from
multimedia presentations