It will be define common input devices of computer. Most input devices that are needed in our daily life.

1.  Input device is any hardware component that allows users
to enter data and instructions
 Data or instructions entered into the memory of
computer
What is Input
1

2. What is a keyboard?
 The most common input device
 Input device that contains keys users press to enter
data into a computer
 Includes typing area,
numeric keypad, and
function keys
Keyboard
2

3. The Keyboard - Standard Keyboard Layout
 A standard computer keyboard has about 100 keys.
 Most keyboards use the QWERTY layout, named for the
first
six keys in the top row of letters.
3

4. • suitable for a wide range of applications
– entering programs
– typing all kinds of documents using a word processor
– entering personal details of customers or patients at a
hospital, etc.
Keyboard Data Entry
4

5. • Data entered at a keyboard is commonly copied
from a source document, and as such
– It is easy to make transcription errors – that is, copy the
data wrongly from the document
– It is time-consuming
– Data entry operators who enter data all day every day
are prone to repetitive strain injury (RSI), a condition
which renders them unable to do any further data entry
Keyboard Data Entry – Disadvantages
5

6. The Mouse
•The mouse can be used
to issue commands, draw,
and perform other types of
input tasks.
•The mouse is a pointing device. You use it to move a
graphical pointer on the screen.
What is a Mouse?
• Two characteristics
 Planar movement
 Buttons
6

7. 1.Pointing: Move the mouse to move the on-screen pointer.
2.Clicking: Press and release the left mouse button once.
3.Double-clicking: Press and release the left mouse button twice.
4.Dragging: Hold down the left mouse button as you move the
pointer.
5.Right-clicking: Press and release the right mouse button.
Using the mouse involves five techniques:
The Mouse - Mouse Techniques
7

8. Two methods for detecting motion
• Mechanical
– Ball on underside of mouse turns as mouse is moved
– Rotates orthogonal potentiometers
– Can be used on almost any flat surface
• Optical
– light emitting diode on underside of mouse
– may use special grid-like pad or just on desk
– less susceptible to dust and dirt
– detects fluctuating alterations in reflected light intensity to calculate relative
motion in (x, z) plane
How does it work?
8

9. What is a trackball?
 Stationary pointing device with a ball on its
top or side
 A trackball is like a mouse turned upside-
down.
 To move pointer, rotate ball with thumb,
fingers, or palm of hand.
 Separate buttons for picking
 Very fast for gaming
 Used in some portable and notebook
computers.
Trackball
9

10. • Small touch sensitive tablets
• ‘Stroke’ to move mouse pointer
• Used mainly in laptop computers
• Good ‘acceleration’ settings important
– fast stroke
• lots of pixels per inch moved
• initial movement to the target
– slow stroke
• less pixels per inch
• for accurate positioning
Touchpad
10

11. – Joysticks are popular for flight
simulator and driving games.
– indirect
pressure of stick = velocity of
movement
– buttons for selection
on top or on front like a trigger
– often used for computer games
aircraft controls and 3D navigation
Joystick
11

12. • Detect the presence of finger or stylus on the
screen.
– works by interrupting matrix of light beams,
capacitance changes or ultrasonic reflections
– direct pointing device
• Advantages:
– fast, and requires no specialised pointer
– good for menu selection
– suitable for use in hostile environment: clean and
safe from damage.
• Disadvantages:
– finger can mark screen
– imprecise (finger is a fairly blunt instrument!)
• difficult to select small regions or perform accurate
drawing
– lifting arm can be tiring
Touch-sensitive screen
12

13. • Converts a document into a series of pixels (picture elements –
these are small squares that, when put together, form a picture).
• The larger the number of pixels, or conversely the smaller each
individual pixel, the better the definition of the final picture.
Scanners
13

14. • Take paper and convert it into a bitmap
• Two sorts of scanner
– flat-bed: paper placed on a glass plate, whole page converted into
bitmap
– hand-held: scanner passed over paper, digitising strip typically 3-
4” wide
• Shines light at paper and note intensity of reflection
– colour or greyscale
• Typical resolutions from 600–2400 dpi
Scanners
14

15. Used in
– desktop publishing for incorporating photographs and
other images
– document storage and retrieval systems, doing away
with paper storage
+ special scanners for slides and photographic negatives
Scanners
15

16. • A technology that allows an input device (e.g.
imaging scanner) to read hand-drawn marks
such as small circles or rectangles on
specially designed paper.
• Can recognise the presence of a mark on a
sheet of paper by light reflection.
• The position of the mark conveys information
to the machine.
• Printing is done using a special type of ink
which the optical scanner does not see.
OMR (Optical Mark Reader)
16

17. • Advantage:
– It is fast, using minimum processing power to process forms
– Costs are predictable and defined
– OMR capture speeds range around 4000 forms per hr
• Disadvantage:
– Cannot read paper if folded or dirty.
– Restricted to multi choice questions.
– OMR cannot recognize hand-printed or machine-printed characters.
– With OMR, images of forms are not captured by scanners so electronic
retrieval is not possible.
– Tick boxes may not be suitable for all types of questions
OMR
17

18. • Also referred to as Optical Character Reader
• Reads text directly from a document.
• Measures the light reflected to determines shape of characters.
• Compares them with examples in memory.
• Advantage:
– Automatic and fast data entry.
• Disadvantage:
– Unreliable
• Uses:
– Reading post codes on printed documents.
– Reading documents for blind people, the contents of which can be output using
a voice synthesizer.
OCR
18

19. • a system that provides a full alphanumeric recognition of printed or
handwritten characters at electronic speed by simply scanning the form.
• Intelligent Character Recognition (ICR) is used to describe the process of
interpreting image data, in particular alphanumeric text.
• Sometimes OCR is known as ICR
OCR
19

20. • All banks use MICR for processing cheques.
• Along the bottom of a cheque the bank’s sort code,
customer account number and cheque number are
encoded in special characters in magnetic ink.
• The amount of the cheque is encoded in magnetic ink when
it is handed in at a bank.
The cheques can then be processed extremely fast by
high-speed MICR devices that read, sort and store the data
on disk.
MICR
20

21. • MICR has several advantages for processing
cheques:
– It is hard to forge the characters
– The characters can be read even if the cheque is
crumpled, dirty or smudged
– The characters are readable by humans, unlike bar
codes
MICR
21

22. • Bar code readers can read bar codes—patterns of printed bars.
• The reader emits light, which reflects off the bar code and into a
detector in the reader. The detector translates the code into
numbers.
• Flatbed bar code readers are commonly found in supermarkets.
Courier services often use handheld readers.
Bar Code Readers
22

23. • A laser scanner reads the reflected laser light from a series of dark and
light coloured lines of varying thickness.
• The different widths of pairs of lines make up a code that can be
converted into a number.
• This number can then be used as the key field relating to a file of items
that have been bar-coded.
• Advantages:
– Faster data entry.
– More accurate.
• Disadvantages:
– Bar codes can be damaged.
– Can be difficult to get the bar code reader into a position to read the bar code on
large items.
Bar code readers
23

24. • Fast-selling items automatically reordered to meet
demand
• Slow-selling items can be identified preventing
build-up of unwanted stock
• Effects of repositioning a given product within a
store can be monitored
• Historical data can be used to predict seasonal
fluctuations very accurately
Benefits of using bar codes
24

25. • Warehousing
– bar coded containers of raw materials are stored in
racks of bins which are also bar coded.
• Transport and distribution
– individual packages are bar coded
• Manufacturing
– work in progress tracked using bar codes
Other uses of bar codes
25

26. • Marketing
– bar coded multiple choice questionnaires
• Medical
– bar codes used to identify blood and other samples
• Libraries
– used to record loans and track stock
• Banking, insurance and local government
– for document control and retrieval.
More uses of bar codes
26

27. • The user speaks the text into a microphone
• Special software interprets the text and displays it on a screen
• Text may be edited using the keyboard and exported to a word
processing package such as Word.
• The accuracy of the voice recognition system is improved by ‘training’
it to a particular user’s voice
Voice data entry
27