Input & Output
Input Hardware
 Devices
that translate
process
 Translates
into a form the computer can
, and
into
Output Hardware
 Devices
that translate information processed by the
computer into a form humans can understand
 Translates
into
, and
Input: Keyboards
 Keyboards: convert letters, numbers, and characters into



Our keyboard – “
Problems with
keyboard”
layout?
Standard
keys desktop standard,

keys for laptops (no numeric keypad)
 Wired

Connect to
via a serial or
port
 Wireless



Require line of sight to connect
Use either
or
technology
Virtual keyboard


Uses
to project a keyboard onto another surface
used with PDAs and smartphones
Input: Pointing Devices

Control the position of the cursor or pointer in the screen and allow the
user to select options displayed on the screen
 Used with
 Most today are


Use reflection of

to determine movement of mouse pointer
position for wrist
 Trackball
A movable
mounted on top of a stationary device
 Good for locations where a
couldn’t move enough
 Good for people with

Input: Pointing Devices

To use: slide your finger over this small flat surface
 Click by
on the surface
 May require more practice to use than a mouse


A
sensitized to receive input from a finger
 Cruder than a mouse, because
are big
 Problems:
that show a
that is not precisely
aligned with the input


input
Use a
 Can use


Problems with
for input rather than typing on a keyboard
to translate
into data
?
Scanners
 Use
equipment to translate images of text, drawings,
and photos into digital form

reflects off image and scanner measures reflection at

Measurements can either be shades of gray or color


Color:
Points are in rows and columns across the image
 Measurements
a file (a “


are stored as digital code (called a
”)
- The more
can be represented.
) in
in each dot, the more colors that
refers to the image sharpness, measured in
Scanners


Photoelectric (optical) scanners that translate
symbols
into digital code
 Left and right-most
are special so that scanner can always
tell whether an image is
or
 The
is then sent to a computer
 The computer looks up the item and displays its name and pricing
info
OCR
 OCR
–
software
 Converts
scanned
from images (pictures of the
) to an
format
 You use this to read in non-computer documents where you
don’t have the source files
Q: Why is this difficult for the computer? Is it difficult for us?
What does this say about the computer’s capabilities?
Q: Who does this help? Can you think of populations who’d
value this technology?
Sound: Audio Input Devices
Translates
sound into
storage and processing
files for
– continuous (like music)
– numbers (in this case, at discrete points in time)



We measure the displacement of air and store the measurements
in a file as a sound file.
Two ways to
audio


A card in a PC that converts
sound (usually from a
microphone) to
sound, stores it in a file, and/or plays it
back to speakers or amp

Uses a standard for the interchange between musical instruments,
synthesizers, and PCs

Speech Recognition Systems
Converts a person’s
representations of
 Usually
by
into digital
and
signal to 200,000 or so stored
Q: what populations would find this most useful?
 Still
not often used in place of the mouse/keyboard for
fast document creation
 Dragon
Dictate
 ScanSoft’s Open Speech Dialog
 Apple Speech Recognition
 ScanSoft’s Navigon MobileNavigator 5
Other Input Hardware

 Use
a light-sensitive
chip to capture
in
form and store them (usually on flash memory
cards)
 Most can be connected to a PC by
or FireWire
 Can allow you to take more pictures and decide which ones
to print and save
 Be aware:

printed at home don’t last nearly as long as those
printed at a photo shop
 Storing photos:
’s may only last 5 – 25 years
Input Hardware
RFID Tags

tags use a tag with a
containing specific
 Scanners
use
to read them and match the
to a
 Enables items to be tracked without physical contact
Drivers put RFID tags in cars to automatically

is tagging certain
with RFID to avoid counterfeits
 Carmakers are using it for car electronic
 RFID tags are implanted under
to aid in recovery
and identification when they get
 Used to scan
for

Q: What other uses can you think of for RFID Tags?
Health & Ergonomics

:
 Studying
the use of
needed to use those
and the
movements

 Results
 E.g.,
from continuous,
motions
Tennis elbow
 Represents
62%of all North American WC claims
 Nearly $15-20 billion in lost work time and WC claims
each year
 E.g.,
 caused
by pressure on the median nerve in the
caused by short repetitive movement

Too much typing, too much mouse use!
,
Carpal Tunnel Syndrome - Prevention
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Keep hands, arms, and fingers strong and flexible
Don’t smoke
Switch mouse hands
Restrict salt intake
Use ergonomically correct keyboard
Keep wrists straight and elevated when typing
Use pad for wrists (only for when resting, not when typing)
Don’t slouch
Type correctly
Take breaks
Do exercises to flex and stretch wrists and hands
Keep hands and arms warm
Use other forms of input
Use voice recognition software
Use larger font


start->control panel-> display->appearance->font size
Use mouse as little as possible