Alternative forms for commands

IInformation Technology, Kontemporor FMIPA UGM

Chapter 5
Input Devices
What Is Input?
The Keyboard
Pointing Devices
Voice Input
PDAs, Tablet PCs, and
Smart Phones
• Digital Cameras

•
•
•
•
•

•
•
•

•

Video Input
Scanners
Terminals
Biometric Input
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What Is Input?
The two basic types of input:


Data




Instructions







Unprocessed text,
numbers, images,
audio, and video
Programs
Commands
User responses

An Input device is
any hardware component used
to enter data or instructions

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The Computer Keyboard
The keyboard areas




Typing area
Numeric keypad
Function keys, special
keys that issue
commands
 Often used with other
keys for shortcuts

Types of keyboards:
Standard USB or PS1
Wireless (communicates via a receiver)

Built-in keyboards (notebooks)





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The Keyboard
Alternative forms for commands


Many programs
ow you to
o use
allow
key combination,
menu, or button to

obtain same result

Key
Combination

Menu |
Command

Copy

Shift+F2 or
Ctrl+C

Edit | Copy

Open

Ctrl+F12

File | Open

P t
Paste

Ct l+V
Ctrl+V

Edit | Paste
P t

Command

Button

The insertion point



Blinking vertical bar that indicates where next
character you type will display

Pointer changes location and shape

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Pointing Devices
A mouse is:


Pointing device that fits under palm of hand


Pointing device controls movement of pointer, also called mouse pointer
mouse buttons



wheel
button

Mechanical mouse


has rubber or metal ball on
underside

Also
 Optical mouse (light)
 Laser mouse
 Wireless mouse

ball

mouse pad
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Pointing Devices
The optical mouse:





Inside each optical mouse is a small
camera that takes more than a thousand
snapshot pictures every second. A
small LED (light-emitting diode)
provides light underneath the mouse,
helping to highlight slight differences in
the surface underneath the mouse.

No moving mechanical
parts inside
Senses light to detect
mouse’s movement

More precise than
mechanical mouse
Connects using a
cable, or wireless

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Other Pointing Devices
A trackball is:



A stationary pointing device
with a ball on its top
To move pointer
pointer, rotate ball

with thumb, fingers, or palm
of hand

A touch screen:



Touch areas of screen with
finger or other device
Often used with kiosks





Latest Developments: micro-touch
privacy glass for liquid crystal displays
Actual touch registers up to 1mm (0.04”)
before the physical touch on the Touch
Surface.
Surface acoustic wave touchscreens
http://www.neuro-logic.com/saw.htm

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Other Pointing Devices
Touchpad and a pointing stick:


Touchpad is small, flat,
rectang lar pointing device
rectangular
de ice
sensitive to pressure and motion



Pointing stick is pointing device
shaped like pencil eraser
positioned between keys on
y
keyboard

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Other Pointing Devices
Joystick and Wheel




Joystick is vertical
lever mounted
on a base
Wheel is
steering-wheel-type
input device


Pedal simulates
car brakes and
accelerator

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Other Pointing Devices
Light pen:


Handheld input device that
can detect light
 The tip of the light pen contains a
light-sensitive element which, when
placed against the screen, detects
the light from the screen enabling
the computer to identify the location
of the pen on the screen.

Stylus:




Looks like a ballpoint pen, but
uses pressure to write text and
draw lines
Used with graphics tablets,
flat electronic boards

A li
light
h pen can work
k with
ih
any CRT-based monitor,
but cannot work with LCD
screens,
projectors et cetera.
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Voice Input
How does voice recognition work?
Step 1. A user dictates text into a microphone.

Step 2. An analog-to-digital converter (ADC) translates

sound waves into digital measurements computer can
process. Measurements include pitch,
process
pitch volume,
volume silences
silences, and
phonemes. Phonemes are sound units such as aw and guh.

10010111010110101100001101

Step 4. To narrow a list down, software presents user with
a list of choices or uses a natural language component to
predict most likely match. User may correct any selection
made
d by
b software.
ft
Natural Language Engine

Step 3. Software compares
spoken measurements with those
in its database to find a match or
li t off possible
list
ibl matches.
t h

Matches

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Other Input
MIDI (musical instrument
digital interface):


External
E
t
l device,
d i such
h as
electronic piano keyboard,
to input music and sound
effects



General MIDI's most recognized
feature is the defined list of
sounds or "patches"
patches . However,
However
General MIDI does not actually
define the way the sound will
be reproduced, only the name
of that sound.
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PDAs, Tablet PCs, and Smart Phones
Entering data into a PDA:

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PDAs, Tablet PCs, and Smart Phones
A docking station is:



An external device that
holds mobile computer
It provides connections to
peripherals

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PDAs, Tablet PCs, and Smart Phones
What is a smart phone?




Users can input and send
text messages, graphics,
pictures, video clips, and
sound files
Many have a built-in or
attachable camera

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Digital Cameras
What is a digital camera?



Allows you to take
digital pictures
Images viewable
immediately on
camera if LCD screen is
provided





Download image files to
p
computer
Post pictures to Web
Print (sometimes with
purpose built printer)
Edit image files using
image editing software

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Digital Cameras
How does a digital camera work?
Step 1. Point to the image to

Step 2. Image is focused on a

photograph and take picture.
g passes
p
into the lens of the
Light
camera.

chip called a charge-coupled
)
device ((CCD).

Step 3. CCD generates an analog

signal that represents the image.
Step 4. Analog
l signal
i l is
i convertedd
to digital signal by analog-todigital converter (ADC).
Step 5. Digital signal processor
(DSP) adjusts quality of image and
usually stores digital image on
miniature mobile storage media in
the camera.

Step
p 7. Using
g software

supplied with the
camera, images are
viewed on screen,
incorporated into
documents, edited, and
printed.

Step 6. Images are transferred to a

computer s hard disk by plugging one
computer’s
end of the cable into a camera and the
other end into a computer; or images
are copied to hard disk from storage
media used in the camera.

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Digital Cameras
Image resolution:





Sharpness and clarity of
image
The higher the resolution,
the better the image quality,
but the more expensive the
camera
Pixel (picture element)
is single point in
electronic image


Greater the number of pixels
allows better image quality
but also means larger image
file size

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Video Input
Video input:


The process of entering full-motion
g into computer
p
images



A Video capture card is an
adapter card that converts
analog video signal into a
digital signal that computer
can use
Di it l video
Digital
id (DV)
camera records video as
digital signals



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Video Input
PC video camera & Web cam


DV camera used to capture video
and still images,
images and to make
video telephone calls on Internet




Also called PC camera

Web cam — video camera
whose output displays on
a Web page
c

c

Video conferencing:


Is when two or more geographically separated
people who use network on Internet to transmit
audio and video data

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Scanners and Reading Devices
Flatbed

What is a scanner?


Light-sensing device that
reads printed text and
graphics


Pen or
Handheld

Used for image processing,
converting paper documents
into electronic images

Sheet-fed

Drum

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Scanners and Reading Devices
Flatbed scanner:
Step 1. Document to be scanned is
placed face down on the glass window.
Step 2. Bright light moves underneath
scanned document.
Step 3. Image of the document is
reflected into a series of mirrors.
Step 4. Light
is converted to
analog electrical
current that is
converted to
digital signal by
an analog-todigital converter
(ADC).

Step 6
6. Users can print image
image,
e-mail it, fax it, include it in a
document, or place it on a Web page.
Step 5. Digital information is sent to memory in the computer to
be used by illustration, desktop publishing, or other software; or it
is stored on disk.
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Scanners and Reading Devices
An optical reader is:


Device that uses light source to read characters, marks,
and codes and then converts them into digital data






Optical character recognition
(OCR) reads characters in
OCR font
Optical mark recognition
(OMR) reads hand-drawn pencil
marks such as small circles
marks,
Bar code scanner

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Scanners and Reading Devices
What is a bar code reader?
Uses laser beams to read bar codes



What is a bar code?



Identification code that consists of a set of vertical lines and
spaces of different widths
Universal
Product
Code (UPC)

Some widely used
bar codes?
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Scanners and Reading Devices
A Magnetic-ink character recognition
(MICR) reader:



Can read text printed with magnetized ink
Banking industry almost exclusively uses MICR
for check
processing

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Scanners and Reading Devices
A data collection device:






Obtains data directly at
location where transaction or
event takes place
Transmits data over
network
or Internet
Often used to assist in stock
control in supermarkets

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Terminals
Point of sale (POS) terminal (s):


Records purchases, processes credit or
debit cards, and updates inventory


Swipe credit or debit card through card
reader — reads customer’s personal data
from magnetic strip
c

c

Automated teller machine (ATM) (s):


Self-service banking machine
that connects to a host
computer through a network

A smart display is:


A thin monitor that detaches from
computer to function as
portable wireless touchscreen

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Biometric Input
Biometrics are used when a system :


Authenticates a person’s identity
by verifying personal
characteristic




Fingerprint scanner captures
curves and indentations of
fingerprint
Hand geometry system measures
shape and size of person’s hand

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Biometric Input
What are examples of biometric technology?





Voice verification system compares live
speech with stored voice pattern
Signature verification system recognizes
shape of signature
Retina & Iris recognition systems


Biometric data is sometimes stored
on smart card
card, which stores
personal data on microprocessor
embedded in card

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Input Devices for Physically Challenged Users
What input devices are available
for those with physical limitations?





Keyguard allows users to rest
hands on keyboard without
accidentally pressing keys
Head-mounted pointer controls
pointer on screen
New developments include gesture
iti and
d computerized
t i d
recognition
implant devices

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