Alternative Input Devices for Students

Alternative Input Devices for Students with Physical Disabilities

Switches:
Switches control the flow of electrical power to a device that the user
wants to turn on or off. Switches can be activated by almost any part of the
body a person is able to voluntarily and reliably control—for example,
switches are available that can be activated by the use of an arm, hand, finger,
leg, foot, head, or chin. They also may be controlled by less obvious move-
ments of the eyebrow, or the rib cage with access through controlled breath-
ing. While the movement does not have to be big, it must be controllable and
reliable, and often considerable training is required before the use of the
switch is reliable.

Basic Adaptive Keyboards:
Basic keyboard adaptations that assist physically dis-
abled students to use computers include replacing standard keys with larger
keys that are easier to see and touch, reducing the number of keys on the key-
board, placing letter keys in alphabetical order, and providing keys that are
brightly colored and easy to read. Other keyboards are much smaller than
their traditional counterparts and have keyboard surfaces that are much more
sensitive to touch. These keyboards are excellent for individuals with a limited
range of motion or for individuals who have a difficult time applying pressure
to keys.

Touch-Sensitive Screens:
Touch-sensitive screens are very popular with young
computer users and with individuals who have severe developmental or phys-
ical disabilities. This technology allows the user to simply touch the computer
screen to perform a function. Many touch-sensitive screens come complete
with multiple screen overlays that can be used to perform a variety of tasks.
Similarly, many companies provide additional software that enables the users
to create their own overlays.

Infrared Sensors with Pneumatic Switches:
Use of an infrared sensor worn on the
head, along with use of a pneumatic switch, can enable physically disabled stu-
dents to interact with the computer. As the user looks at the computer screen,
the cursor follows the user’s head movement. Moving the head to the left
moves the cursor in the same direction on the screen. Thus, users can position
the cursor anywhere on the screen by moving their head left, right, up, or
down. The pneumatic switch, which is activated by inhaling or exhaling
through a plastic tube, enables the user to use the mouse. When the user sips
or puffs on the switch, the computer responds as if the mouse button had been
clicked. In this manner, the user can move a cursor and click on items dis-
played on the computer screen. Special software is used in conjunction with
these movements to allow the user to type out information on a facsimile of a
keyboard that is displayed on the computer monitor.

Voice Recognition:
Using voice recognition software, the user can bypass the key-
board and just speak to the computer. By programming the computer with a
set of predefined instructions, the user can control the computer by verbally
issuing commands into a microphone. In most cases, the reliability of the
system can be enhanced by having the user “train” the computer to recognize
his or her speech patterns. Voice recognition systems allow students to operate
a variety of application programs, to dictate to a word processor, and to enter
data into spreadsheets.