Page 493 - Biomedical Engineering and Design Handbook Volume 2, Applications

APPLIED UNIVERSAL DESIGN 471

TABLE 16.4 Sample Input/Output Devices
Name Description
Amplification/magnification Sound may need to be amplified or a display magnified.
Braille display Multiple-character display in which pins extend to represent Braille characters and are
continuously refreshed by the computer.
EEG switch Receiver worn on the forehead can detect EEG signals to activate a switch.
Electromyographic (EMG) switch A surface electrode detects a muscle contraction and triggers this switch; it can use
small, controlled muscle movements.
Environmental control unit (ECU) A “black box” that accepts most input devices (e.g., sip and puff and touch switches) and
may be connected to multiple devices (e.g., telephones, bed controls, lamps, and
appliances); it has the ability to scan through different options, such as “call home,”
“turn lamp on,” and “increase the volume of the television,” with a minimum of one
switch.
Eye/eyebrow switch and eye trackers Detect blinks, eyebrow motion, or the wrinkling of the forehead; eye trackers are more
sophisticated systems that can detect the coordinates of the eye to replace a computer
mouse, etc.
Flashers A smoke detector, door bell, or a baby’s cry can alert a person who is deaf with a
flashing light.
Functional electrical stimulation (FES) Electrodes inserted into muscles to activate (stimulate) selected muscles for those with
paralysis.
Optical pointer Laser that can be mounted on a user to allow for precise pointing.
Proximity and temperature sensors Technologies include ultrasound and can detect the presence of a person through his or
her motion or body temperature.
Remote I/O devices These include remote keyboards that allow you to roll up in a wheelchair near your
personal computer without having to physically connect or carry a laptop; television,
lamp, and appliance remotes can be purchased at local electronics stores; these
include Bluetooth, infrared and FM-based systems.
Scanning device Using as little as a single input device, the device switches between multiple output
options.
Sip-and-puff switch Ultrasensitive pneumatic switch actuated by slight mouth pressure.
Skin surface stimulation/subdermal Electrodes are placed on the surface of the skin or implanted to provide sensory
stimulation 10 feedback.
Speech output These include computer-generated speech synthesizers and systems that replay
human speech.
Tactile Includes textured surfaces, scales, thermometers, and watch faces that can be felt
(raised and Braille lettering).
Touch pads Adhesive-backed flexible plastic pad; it is activated by touch and can be washed.
Touch switch Single switch activated by very light pressure.
Vibrators Includes smaller vibrators used in pagers and larger units that may be placed
underneath a mattress to wake a person who is deaf.
Voice- and sound-activated systems From systems that respond to a clap to word processors that can type what you speak,
the sophistication and price cover a broad spectrum.

the controls positioned appropriately? Is there a concern for repetitive-motion injuries? A person
might have limited neuromuscular control or may be wearing gloves while operating the device out-
doors. The person may have low vision or be in a dimly lit room. Is the user color-blind?
When designing for a specific person, certain anthropometric measurements (mass, lengths, radii
of gyrations, etc., of the human body) can easily be made. These include height, weight, and reach.
What if you are creating a product for the mass market? One approach is to use anthropometric
tables. You can estimate, for example, the height of the fifth, fiftieth, and ninety-fifth percentiles of
American women. However, who do you design for? If you design for even the ninety-fifth per-
centile, you are still excluding the tallest 5 percent. What if you are attempting to estimate the mass