Input devices capture information from the external environment and translate it into a form that can be processed by computers. Common input devices include keyboards, pointing devices like mice and trackballs, game controllers, scanners, styluses, microphones, digital cameras, and webcams. Trackballs are upside-down mice that rotate in place to move the cursor, requiring less workspace but more cleaning than mice. Touchpads and pointing sticks are found on laptops to control the cursor. Light pens, touch screens, styluses, graphic tablets, and pen-based devices allow entering information via touch. Voice recognition and handwriting recognition translate spoken words and handwriting into text.

2. Input Devices
• Input device captures information and translates it into a form
that can be processed and used by other parts of your computer.
Keyboards
Pointing devices
Game controllers
Scanners
Styluses
Microphones
Digital cameras
Web cams
p. 5.130 Fig. 5-1

3. Trackball
 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. The user rolls the ball to
direct the cursor to the desired place on the screen and can
click one of two buttons (identical to mouse buttons) near
the trackball to select desktop objects or position the
cursor for text entry.
 very fast for gaming

4. Trackball
Advantages of using a trackball are:
 Less work surface is required for trackball to function.
 Trackball allows continuous and fast scrolling and
does not require repositioning.
 Unlike other input devices, trackballs require only
minimal cleaning
Disadvantages of using a trackball are:
 Compared to mouse, trackballs are physically larger.
 As they are little more expensive

5. Touchpad/Trackpad
 Small, flat, rectangular
device that is sensitive to
pressure and motion
 You move the pointer by
sliding your finger
around
 You tap the pad to
initiate a “click”
 Most often found on
notebook computers

6. Pointing Stick
 A pointing stick is a small
joystick used
a pointing device typically
mounted centrally in a
computer keyboard. Like
other pointing devices
such as mice, touchpads or
trackballs, operating
system software translates
manipulation of the device
into movements of
the pointer or cursor on
the monitor.

7. Pointing Stick
 Pressure sensitive
device shaped like a
pencil eraser that is
positioned between
keys on the keyboard.
 First developed by
IBM for their
notebook computers

8. Joystick & Wheel
 These devices are used
for game software or
flight and driving
software.
 The name joystick comes
from early history in
aircraft control.
 Joystick: a vertical lever
mounted on a base. It is
easily moved in multiple
directions.
 Wheel: a steering-wheel
type device used in auto
simulation games

9. Light Pen
 A handheld device that contains a light
source or can detect light.
 Some require specially designed
monitors.
• One problem is hand fatigue. A light pen
is a small ‘pen-shaped’ wand (stick),
which contains light sensors.
• It is used to choose objects or commands
on the screen either by pressing it against
the surface of the screen or by pressing a
small switch on its side.
• A signal is sent to the computer, which
then works out the light pen’s exact
location on the screen.
• The advantage of a light pen is that it
doesn’t need a special screen.

10. Light Pen

11. Touch Screen
 A touch sensitive
display you interact
with by touching areas
of the screen with your
fingers
 Touch Screen is a video
display screen that
receives input from
touch of finger.
 Example: ATM
machines

12. Touch Screens
 Human points to a selection on the screen
 A touchscreen is an input device and normally layered
on the top of an electronic visual display of an
information processing system.
 A user can give input or control the information
processing system through simple or multi-
touch gestures by touching the screen with a special
stylus or one or more fingers.

13. Styluses
• Stylus is an input device consisting of a thin stick that uses
pressure to enter information or to click and point
• Styluses are used with:
PDAs
Tablet PCs
Graphics tablets

14. Pen-based Computing
 Small hand-held devices
 Electronic pen (stylus)
 Pointer
 Handwritten input
 Personal Digital Assistants
(PDA)

15. Graphic Tablet
 It is a flat, rectangular
electronic plastic board
 Also called a “digitizer”
or “digitizing tablet”
 Used along with a stylus
 One use: architects, map
makers, artists, and
designers create
drawings and sketches
using it

16. Tablet PC
 Uses a digital pen
 Microsoft version uses
Windows XP Professional
 It has handwriting and voice
recognition capabilities
 Take notes and save
them
 Convert handwritten
documents into typed
documents

17. Voice Recognition
 Voice recognition: a
computer’s capability of
distinguishing spoken
words.
 You speak into a
microphone and the
words display on the
screen.
 You can also edit and
format a document by
speaking or spelling
instructions.

18. Handwriting Recognition
 Process by which
handwritten letters and
symbols are translated
into characters that the
computer understands.
 Used by many notebook
computers and handheld
computers.
 Requires the use of a
stylus.

19. Microphones
• Microphones are used to input
audio
• Three main types of microphones
are:
Desktop microphones
Headsets
Directional microphones
• Speech recognition is increasingly
being included in application
software

20. Digital Cameras
 Digital cameras are used to:
• Download images to a computer
• Produce videos
 Resolution is measured in Megapixels. Higher the resolution,
better the image quality.
 The optical system of a digital camera works like a film camera, in which a
typical lens are used to adjust electronic image sensor lighting. ...
Advanced digital cameras facilitate manual control of most functions.
A digital camera is also known as a digicam.
 Digital cameras have become standard equipment for designers of all
kinds.
 In Web page design, digital cameras enable designers to shoot a subject
and quickly load the images onto their computers.
 This process saves the step of acquiring existing photographs or developing
and printing film-based photos.
 Graphic designers can edit and enhance digital photographs, using photo-
editing software.

21. Webcam
 A digital camera designed to take
digital photographs and transmit
them over the internet.
 (WEB CAMera) A video camera
that attaches to a computer
typically via USB or that is built
into a laptop or desktop screen.
 It is used mostly for video
phoning over networks such as
Skype as well as to continuously
monitor an activity and deliver
the video to a Web server for
public or private viewing.

22. Scanner
 A scanner, simply put, is a device used to analyze(examine)
an image and process it. A scanner can be used to input
pictures and text into a computer. There are different types
of scanner:
 Flatbed Scanners
 Sheet-fed Scanners
 Handheld Scanners
 Drum Scanners

23. Flatbed Scanner
 Used for scanning most documents,
photos, and even flat objects from a PC or
laptop
 Works like a copy machine
 Scans documents placed face down on the
glass (scan bed)
 Most common type of scanner
23

24. Sheet-fed Scanner
 More portable(convenient)
than a flatbed scanner
 Used to scan paper
documents and photos
 The paper moves through the
scanner
 Usually smaller than a flat-
bed and portable
24

25. Handheld Scanner
 Smaller than the previous
two scanners
 The user must move the
scanner across the
document
 Image quality is usually
lower
25

26. Drum Scanner
 Used by the publishing
industry
 Document is placed on a
glass cylinder
 Generates very high-
quality scans
26

27. 27
Bar codes
•A bar code is a set of lines of different thicknesses that
represent a number
•Bar Code Readers are used to input data from bar
codes. Most products in shops have bar codes on them
•Bar code readers work by shining a beam of light on
the lines that make up the bar code and detecting the
amount of light that is reflected back. Usually read by
laser scanners, they can also be read using a camera.

29. Optical Character Recognition
(OCR)
 Stands for "Optical Character Recognition." OCR is a
technology that recognizes text in scanned documents.
 OCR software processes a digital image by locating and
recognizing characters, such as letters, numbers, and symbols.
Some OCR software will simply export the text, while other
programs can convert the characters to editable text directly in
the image. Advanced OCR software can export(transfer) the
size and formatting of the text as well as the layout of the text
found on a page.
 OCR technology can be used to convert a hard copy of a
document into an electronic version ( soft copy). For example,
if you scan a multipage document into a digital image, you can
load the document into an OCR program, which will recognize
the text and convert the document to an editable text file.
Some OCR programs allow you to scan a document and
convert it to a word processing document in a single step.
29

30. Optical Character Recognition
(OCR)