2. Input devices
• purpose
• entering data into a computer system
• issuing instructions (commands) to a computer
• input device
• transforms data from the user into a form that a
computer system can process
• together with appropriate software (device drivers)
4. Keyboard
• A keyboard contains keys that allow a user to
enter data and instructions into the computer.
All computer keyboards have a typing area that
includes the letters of the alphabet, numbers,
punctuation marks, and other basic keys.
5. Mouse
• A mouse is the most
widely used pointing
device with a GUI
environment on
personal computers.
A mechanical mouse
has a rubber ball on
its underside to
detect movement of
the mouse. An
optical mouse uses
devices that emit
and sense light to
detect the mouse's
movement.
Advantages
• A mouse is user-friendly
for computer beginners.
• A mouse is easy and
convenient to use with a
graphical user interface.
6. Trackball
• A trackball is a stationary
pointing device with a ball
mechanism on its top. A
trackball is a
computer cursor control
device used in many
notebook and laptop
computers. The trackball
is usually located in front
of the keyboard toward
the user. Essentially, the
trackball is an upside-
down mouse that rotates
in place within a socket.
7. Graphic Tablet:
• A graphics
tablet or digitizer is a
computer input device that
enables a user to hand-draw
images, animations and
graphics, similar to the way
a person draws images with
a pencil and paper. These
tablets may also be used to
capture data or handwritten
signatures. It can also be
used to trace an image from
a piece of paper which is
taped or otherwise secured
to the surface. Capturing
data in this way, either by
tracing or entering the
corners of linear poly-lines
or shapes is called digitizing.
8. Data Glove
• Data Glove or wired
glove (sometimes called a
"dataglove" or "cyberglove")
is an input
device for human–computer
interaction worn like a
glove.
• Various sensor technologies
are used to capture physical
data such as bending
of fingers. Often a motion
tracker, such as
a magnetic tracking device
or inertial tracking device, is
attached to capture the
global position/rotation data
of the glove
9. Touchpad
• It is a small pressure-
and motion-sensitive
area on a portable
computer that you can
use to move the
mouse pointer. When
you move your finger
across the pad, the
mouse pointer on the
screen moves in the
same direction. A
touch pad is an
alternative to a
mouse.
Advantages of a touch
pad include
• Easy and Fast one
finger control.
• Ideal for portable
devices
Disadvantages of using
a touchpad include
• Expensive & found in
specific devices e.g.
laptops
10. Touch screen
• A touch screen is an input/output touch-
sensitive display. Touch screens are often used
for information kiosks located in department
stores, hotels, airports, and museums. Touch
screens are also used for ATM machines to
allow easy access of bank accounts.
11. Joystick
• A joystick is a pointing
device with a vertical
lever mounted on a
base. The lever
usually includes
buttons called
triggers, which
activate certain
events when pressed.
Joysticks are mainly
used for computer
games and
ultrasound scanners
in hospitals.
12. Light Pen
• A light pen is a pointing
device that can detect
the presence of light.
Light pens are used by
health care
professionals (such as
doctors and dentists)
and design work.
A light pen is
a computer input
device in the form of a
light-sensitive wand
used in conjunction
with a computer's CRT
display.
13. Scanner
• A scanner is a light-sensing input device that converts
printed text and graphics into a digital form that can be
further processed by the computer.
• Popular types of scanners are:
• Flatbed scanner: It works like a copy machine except that
it creates a file of the document rather than a paper copy.
• Handheld scanner: It can be manually passed over the
image to be scanned. A portable device you can use to copy
an image from paper to your computer. Hand-held scanners
are ideal for capturing small images, such as signatures and
logos. A hand-held scanner is smaller, less expensive, and
more portable than a flatbed scanner.
