The document provides an overview of computer hardware and input devices. It discusses the basic components of a computer system including the input, processing, storage and output units. It then describes various commonly used input devices such as keyboards, mice, scanners, microphones, webcams and touchscreens. Specific input devices like optical mark readers, bar code readers and digitizers are also explained along with their uses.

1. Introduction to Computer
Lecture # 5
Course Instructor : Sehrish Rafiq
Govt. Girls Degree College Maneri Swabi
Higher Education Department KP

2. LectureOverview
• Computer Hardware
• Organization of a computer system
• Input Devices

3. ComputerHardware
• The physical components of a computer system are known as
hardware.
• Hardware refers to machines in computer system.
• Those components of a computer system which can be seen,
touched and felt are known as hardware.
• The mechanical and electrical components of a computer system are
known as hardware.

4. Organizationof a ComputerSystem
• Every digital computer is made of four basic units.
 Input Unit
 Central Processing Unit
 Storage Unit
 Output Unit

5. Responsibilitiesof Input Unit
• It accepts or reads instructions or data from outside world.
• It converts these instructions and data in computer acceptable
form(machine language).
• It supplies the converted instructions and data to the computer
system memory for further processing.

6. Responsibilitiesof ProcessingUnit
• Execution of program instructions
• Control other units of computer

7. Responsibilitiesof Output Unit
• It accepts the results produced by the computer which are in coded
form (machine language) and hence cannot be easily understood by
humans.
• It converts these coded results in to human understandable form.
• It supplies the converted results to outside world.

8. Responsibilitiesof StorageUnit
• Store data and instructions required for processing (received from
input devices).
• Store intermediate results of processing.
• Store final results of processing before they are released to an
output device.

9. Input Devices

10. Commonlyused input devices
• Keyboard devices
• Point and draw devices
• Data scanning devices
• Digitizer
• Electronic cards based devices
• Microphones
• Webcams
• Speech recognition devices
• Vision based devices

11. KeyboardDevices
• Allow entry in to a computer by pressing a set of keys (labeled
buttons) neatly mounted on a board connected to a computer
system.
• 101-keys QWERTY keyboard is most popular.
• In laptops the keyboard buttons are mounted in the machine and
are not on a separate board, therefore it is called keypad.

12. KeyboardDevices

13. Point & DrawDevices
• Used to rapidly point to and select a graphical icon or menu item from
multiple options displayed on the screen.
• Used to create graphic elements on screen such as lines, curves and
freehand shapes
• Examples:
Mouse
Track ball
Joy stick
Light pen
Touchpad
Touch screen

14. Mouse
• It is a hand-held pointing device that detects two-
dimensional motion relative to a surface.
• This motion is typically translated into the motion of a pointer on
a display, which allows a smooth control of the graphical user
interface.
• Types of mouse
Mechanical mouse
Optical mouse

15. TrackBall
• It is a pointing device which consists of a ball held by a socket containing
sensors to detect a rotation of the ball about two axes.
• It is like an upside-down mouse with a ball that sticks out.
• The user rolls the ball with the thumb, fingers or the palm of the hand
to move a cursor.
• Applications
 General Purpose Computers
 Radar consoles in an air-traffic control room
 Sonar equipment on a ship or submarine

16. Joy Stick
• A joystick is an input device consisting of a stick that pivots on a base
and reports its angle or direction to the device it is controlling.
• Joysticks are often used to control video games, and usually have
one or more push-buttons whose state can also be read by the
computer.
• It performs the same function to the arrow keys in the keyboard but
they provide eight direction movement.
• Applications
Video games
Controlling flight of an aircraft
controlling cranes, trucks, underwater unmanned vehicles

17. Light Pen
• A light pen is an input device which looks like an ordinary pen but its
tip is a contains light sensitive detector.
• It is used in conjunction with a computer's CRT display.
• When its tip touches the screen, the computer locates its position in
the form of X-Y coordinates.
•
• It allows the user to directly point to displayed objects or draw on
the screen in a similar way to a touchscreen but with greater
positional accuracy.

18. Touch pad
• A touchpad is also known as a track pad.
• It is a pointing device which contains a tactile sensor.
• It is a specialized surface which can translate the motion and
position of a user's fingers to a relative position on screen.
• It is a common feature of laptops and is used as a substitute for a
mouse where desk space is scarce.
• Because they vary in size, they can also be found on personal digital
assistants (PDAs) and some portable media players.
• Wireless touchpads are also available as detached accessories.

19. Touch Screen
• A touchscreen is a computer screen that can be used by touching it
with a finger or a stylus pen.
• It enables the user to interact directly with what is displayed.
• It can be described as a touchpad with a screen built-in to it.
• Today, all kinds of devices, both big and small, make use of
touchscreens.
• However, tablet computers and smartphones have made them
popular and are the most widely known and used products that use
touchscreens.

20. Touch ScreenDevices

21. • Input devices that enable direct data entry in to a computer from
source document are known as data scanning devices.
• They eliminate the need to key in text data in to computer.
• Due to reduced human effort in data entry, these devices improve
data accuracy and increase the timeliness of information processed.
• They demand high quality of input documents.
• Some of them are capable of recognizing marks or characters.
• Examples:
• Image Scanner
• Optical mark Reader
• Bar Code Reader
• Magnetic Ink Character Reader
DataScanning devices

22. • Scanner translates paper documents in to electronic format for storage
in computer.
• Electronic format of a scanned image is its bitmap.
• Stored image can be altered or manipulated using image processing
software.
ImageScanner

23. • It is a scanner equipped with a character recognition software.
• It photo-scans text character-by-character, analyzes the scanned-in
image, and translates it into character codes.
• It utilizes light beams to read alpha numeric characters of both hand
written or typed text.
• It is extremely complex because it is difficult to make computer recognize
an unlimited number of fonts.
• They are used for large volume processing applications such as scanning
of utility bills of customers etc.
OpticalCharacterRecognition(OCR)
Device

24. • It is a scanner capable of recognizing a pre-specified type of mark by
pencil or pen.
• It can capture human-marked data from document forms such as
surveys and tests.
• They are used to read questionnaires, multiple choice examination
paper in the form of shaded areas.
OpticalmarkReader

25. • A bar code reader is an electronic device that can read data in the
form of bars/lines known as Universal Product Code (UPC) in to the
computer.
• UPC contains the detailed product information and is used for
labeling goods and stock in a shop.
• After detecting the code, it transmits the product data in to
computer which locates item price, updates the stock and prints the
receipt for the customer.
Bar Code Reader

26. • MICR is a device capable of recognizing characters written with special ink
and in specific font.
• It is mostly used by banks for faster processing of large volume of
cheques.
• Numbers and characters (consisting of check number and account
number) are printed using Magnetic Ink on bottom of cheques.
• MICR provides a secure, high-speed method of scanning and processing
information.
• MICR supports only 14 symbols.
MagneticInk CharacterReader
(MICR)

27. Magnetic Ink Character Reader

28. • Digitizer is an input device used for producing pictorial images.
• It enables the user to write/draw something on the tablet like
surface using stylus.
• The tablet senses where the stylus touched it and sends the x-y
coordinates of each point to the computer.
• It is mostly used by architects and engineers to design cars,
buildings, medical devices, robots etc.
• It is also used for digitizing maps available in paper form.
Digitizer

29. • Electronic cards are small plastic cards having encoded data
appropriate for the application for which they are used.
• Electronic card reader is used to read data encoded on an electronic
card and transfer it to the computer for further processing.
• Used together as a means of direct data entry in to a computer
system.
• Used by banks for use in Automated Teller Machines (ATM’s) and
organizations for controlling access of employees to physically
secured areas.
ElectronicCard Reader

30. Microphone
• Microphone is an input device to input sound that is then stored in a
digital form.
• The microphone is used for various applications such as adding sound
to a multimedia presentation or for mixing music.

31. Webcam
• A webcam is a video camera that is used for capturing snaps or
videos.
• When "captured" by the computer, the videos/ pictures may be
saved, viewed or sent on to other networks using internet or can be
e-mailed as an attachment.
• When sent to a remote location, the videos/ pictures may be saved,
viewed or on sent there.
• A webcam is generally connected by a USB cable or built into
computer hardware, such as laptops.

32. SpeechRecognitionDevices
• Input device that allows a person to input data to a computer by
speaking to it is known as speech recognition device.
• Today speech recognition devices are limited to accepting few words
within a relatively small domain and can be used to enter only
limited kinds and quantities of data.
• Types of speech recognition devices
• Single word
Recognize a single word
Speaker independent
• Continuous speech recognition systems
 Recognize sentences
Speaker dependent

33. Usesof speechrecognitionsystems
• For inputting data to a computer by user in situations where their
hands are busy or their eyes must be fixed on a measuring
instrument or some other object.
• For data input by dictation of long text or passage for later editing
and review.
• For authentication of a user by a computer system based on voice
input.
• For limited use of computers by individuals with physical disabilities.

34. Vision-Input Systems
• Allow computer to accept input just by seeing an object.
• Input data is normally an object’s shape and features in the form of
an image.
• Mainly used today in factories for designing industrial robots that
are used for quality-control and assembly processes.