Input & Output

Input HardwareDevices that translate into a form the computer can

processTranslates , and into

Output HardwareDevices that translate information processed by the

computer into a form humans can understandTranslates into , and

Input: KeyboardsKeyboards: convert letters, numbers, and characters into

Our keyboard – “ keyboard” Problems with 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 for input rather than typing on a keyboard Can use to translate into data

Problems with ?

ScannersUse 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 are stored as digital code (called a ) in

a file (a “ ”) - The more in each dot, the more colors that

can be represented. 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 files for storage and processing – 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 into digital representations of and Usually by 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 saveBe 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 HardwareRFID 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 and the movements needed to use those

Results from continuous, motions

E.g., Tennis elbowRepresents 62%of all North American WC claims Nearly $15-20 billion in lost work time and WC claims

each yearE.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

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