Below blind computer user and researcher John GArdner describes his
accessible graphing calculator in a csun paper. The triangle project is
funded by a grant from the national Science Foundation. If you believe
that this research is valuable and should continue to be funded, by all
means contact Larry Scadden at NSF at mailto:[log in to unmask]
Larry is a blind computer user himself and would likely welcome feedback
and comment from end users. If we want access like this to continue, we
must let our concerns be known about research priorities for federally
funded science and technology research and accessibility.
kelly
The Accessible TRIANGLE Graphing Calculator
Randy Lundquist and John Gardner
Science Access project
Department of Physics
Oregon State University
Corvallis, OR 97331-6507
[log in to unmask], [log in to unmask]
Introduction
Graphing calculators have become a standard tool in American
classrooms. They are used in math and a number of scientific fields.
Lack of an adequate accessible graphing calculator for blind children
is often cited as one of the major "missing technologies" affecting
education of blind children.
The Science Access project has developed a Windows 95 program that can
be used on a small notebook computer as a powerful scientific
calculator, including the ability to compute and plot functions y(x).
The plot is visible on the screen and can also be "viewed"
conveniently in audio. This program will be a part of the Windows 95
TRIANGLE application but is also being made available as a stand-alone
TRIANGLE Graphing Calculator application.
TRIANGLE is self-voicing and works with any speech engine that fully
conforms to the Microsoft speech interface (SAPI). A blind user can
use a Windows 95 screen reader configured to "go to sleep" when
opening or switching into TRIANGLE or the TRIANGLE Calculator program.
In principle these could also be accessible through an on-line braille
display. Even the audio graphing function can be replicated by a
moving icon on a braille display. However this possibility cannot
easily be incorporated at the present time. When the Microsoft braille
interface is finalized and is supported by one or more popular braille
displays, we hope to add self-brailling/display capability.
We believe that the TRIANGLE Calculator largely fulfills the need for
a graphing calculator usable by blind and dyslexic people. Although a
notebook computer is more expensive and bulkier than a standard
graphing calculator, any person with print disabilities should, in our
opinion, be using a computer for reading and writing anyhow. Even in
classroom situations, a print impaired student can access a notebook
computer in audio through an inexpensive earphone such that other
students are not disturbed. We also anticipate that the TRIANGLE
Graphing Calculator may be very useful for many people who are not
officially "print-impaired", in particular the large group of
"auditory learners" who often have difficulty interpreting visual
graphs.
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Calculator Functionality
The TRIANGLE Graphing Calculator has an on-screen calculator modeled
on the scientific calculator that is bundled with Windows. It can be
used by a sighted person with a mouse to click the buttons. Each
button has an intuitive keyboard equivalent that permits sighted or
print-impaired users to make calculations rapidly using the keyboard
only. If self-voicing is enabled, each key function is spoken as it is
exercised. It is also possible to tab among all keys and click them
with spacebar. A context-sensitive help file gives the keyboard
equivalent for each button and explains its function. The latter
capability should make the calculator friendly to learn and use.
This calculator has two expression evaluators that permit a user to
enter an arbitrary function of x and plot one or both expressions. The
audio plot can display either function separately or display their sum
or difference. Constants and expressions can be defined and stored for
later use.
_________________________________________________________________
The Audio Plot
The audio plot displays y vs. x by mapping the x axis to time and the
y axis to tone. Preliminary results from [Comparison tests] made by
several hundred sighted undergraduate and graduate students have
indicated that simple audio graphs of this type are almost as
effective in conveying information as visual graphs.
The primary disadvantage of audio graphs relative to visual graphs is
difficulty of detecting curvature. For example, student testers could
differentiate between the graphs y=x and y=x squared more accurately
with visual graphs than with audio tone plots.
When the tone plots were enhanced by adding "tick mark" beats, the
differences between these two tone graphs became much more obvious to
test subjects. These tick marks have a constant repetition rate if the
line is straight but increase in rate if the graph curves up as with
the plot of x squared.
Calculator users are provided with several tone plot options including
playing of tick marks and suppressing the zero point so that only the
shape of the graph is played. The user can step through the graph in
either the positive or negative x direction, can search for special
points such as maxima, minima, or zeros. The x and y coordinates can
be read at any point, or a table of values read in tabular form.
The TRIANGLE Graphing Calculator program is available in beta form and
can be downloaded from the SAP web site. We are unable to supply the
required SAPI speech engine but can recommend vendors for those that
work well. At the time this paper is written, the only popular speech
engine that is fully compatible with the MS speech interface, and
therefore the only one that works properly with the TRIANGLE Graphing
Calculator, is FlexTalk. However, we expect several others to be
available in 1999 because of the recent release of much better SAPI
interface controls by Microsoft that speech engines can now use as a
test of compliance.
_________________________________________________________________
Acknowledgements
This research was supported in part by the National Science
Foundation.
_________________________________________________________________
References
Science Access Project URL: http://dots.physics.orst.edu/ A discussion
of Microsoft's Speech Application Programmers Interface (SAPI) is
available at: http://research.microsoft.com/stg/ [Comparison tests]
http://www.physics.orst.edu/~sahyun/survey/
_________________________________________________________________
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