------------------------------------
AUTHOR: MAIL.BLINDL
------------------------------------
ASSISTIVE TECHNOLOGY IN THE SCIENCE LABORATORY:
A TALKING LABORATORY WORK STATION FOR
VISUALLY IMPAIRED SCIENCE STUDENTS
David Lunney
Department of Chemistry and
Science Institute for the Disabled
East Carolina University
Greenville, NC 27858
internet: chlunney@ecuvm.cis.ecu.edu
Much assistive technology for people with disabilities has been developed
in the last ten years or so, but the developers of such technology usually
quit as soon as they have provided access to computers. But to chemists,
physicists, and engineers, that seems to be only half the job: computers are
great laboratory tools, and if you connect a suitably adapted computer to
instruments and sensors in a laboratory and provide it with suitable data
acquisition and data analysis software, you have a great way to make careers
in science and engineering more accessible to people with disabilities.
Robert C. Morrison and I first became interested in the problems of
disabled students in the laboratory in 1977, when Richard V. Hartness, a blind
chemistry student, brought them to our attention. We decided to use high
technology to develop a flexible, microcomputer-based aid that could give
visually impaired college science students independent access to accurate
measurements performed with scientific instruments. Our research group's
efforts (which were funded by the U. S. Department of Education) culminated in
a luggable, 42-pound, talking, whistling, industrial-strength data acquisition
computer that cost $8000 a copy and was custom-built from expensive industrial
modules. The group had written about 300 pages of FORTRAN software for the
machine, and it could help a visually impaired chemistry student to perform
many instrumental measurements with maximum independence. It was an
impressive machine, but I couldn't find any company that was willing to build
it. I was sure that we had designed a great tool for visually impaired
chemistry students, but the prevailing political climate was not receptive to
expensive high tech adaptations for disabled students. Also, we were just too
far ahead of widely available technology. (This was in the mid-eighties.)
The available technology has now finally caught up with us, and it is now
possible to replicate most of the functions of our original $8000 machine at
much lower cost. For example, IBM has introduced the Personal Science
Laboratory (PSL), a versatile, modular data acquisition system designed for
performing computer-aided experiments in school laboratories. The PSL
communicates with a host computer through a standard serial port, and reads
its various sensor probes upon receiving commands from the host. (It has
sensors for pH, temperature, light intensity, and distance.) The cost of the
PSL is moderate: the price of a PSL starter kit is about $500. Also, sound
cards have now made it possible to produce highly intelligible synthetic
speech and all sorts of other noises at quite low cost: for example, the low
end Sound Blaster card by Creative Labs has street price of about $75.
We are taking advantage of these new developments to write software
intended to make laboratory measurements more accessible to visually impaired
students from the middle school through college, using a talking, whistling,
musical, large text laboratory work station assembled from widely available,
moderately priced components. The work station hardware consists of an IBM-
compatible personal computer, IBM's Personal Science Laboratory, a digital
multimeter with computer output, a Creative Labs Sound Blaster sound card,
and an electronic balance.
The thorough documentation that IBM provides for the PSL has made it
possible for us to write our own software for reading the output of the PSL's
temperature, light, and pH probes; the readings are spoken by the Sound
Blaster. This software is not complete yet, but the core procedures for
reading and controlling the PSL have been written, and adding additional
features should be straightforward.
With the addition of an electronic balance to the PSL-computer system, we
have a lab work station which can enable a visually impaired student to make
independent measurements of the basic quantities mass, temperature, pH, and
light intensity. With the further addition of a low-cost Radio Shack Micronta
digital multimeter (DMM) equipped with a serial port, we also have the ability
to measure AC and DC voltages and currents, resistance, frequency, and
capacitance.
A separate program for the Micronta DMM (which operates entirely
independently of the PSL) gives spoken readings through the Sound Blaster, and
displays the readings in very large text on the screen; readings can be stored
in a disk file for later analysis. The program announces the meter's ranges
as they are changed, and also tells the user if there is an overflow. If the
meter in a hazardous range, the Sound Blaster makes obnoxious noises and gives
the user a spoken warning.
A DMM module is available for the PSL, but it costs $350 (on top of the
cost of the PSL), whereas the Micronta DMM costs only $130. The Sound
Blaster-DMM combination at a total cost of about $220 is surely the world's
cheapest talking data acquisition system!
We are also developing a versatile data analysis program which uses
varying pitches, speech, and large text and graphics to enable visually
impaired students to examine experimental data and some important math
functions. The use of audible pitches to represent the values of a
variable is a very old method, but in the early 1980's our group at East
Carolina added a new twist by giving the user the ability to scan or step
through the data in either direction, and by having a speech synthesizer
speak the numerical values of the variables upon command. The rising and
falling pitches enabled a visually impaired student to locate peaks and
other interesting qualitative features in a set of experimental measure-
ments, and the speech output gave quantitative data. The newly revised
version of this program runs on an IBM-compatible PC and displays large text
and a visual graph in addition to tones and speech. It uses an external
speech synthesizer, and runs in conjunction with a screen magnification
program which can enlarge graphs and text. (We are now adapting the program
to speak through the Sound Blaster sound card.)
The updated data analysis program includes all the features of the
original and many important new capabilities. As in the original program, the
user can locate peaks and troughs easily because maxima and minima in the data
produce maxima and minima in the pitch. The user can scan or step through the
data, and can control the scan rate over a wide range.
At any time, typing "x" on the keyboard causes the machine to speak the
current value of the independent variable. Similarly, typing "y" produces a
spoken value for the dependent variable. To improve auditory resolution, the
user can jump the frequency up and down over three octaves to find the
frequency range where pitch discrimination is best.
We included visual output in the form of color graphs and large text to
accommodate visually impaired students who have usable vision; the progress of
the data scan is indicated on the graph by a heavy vertical cursor line. The
user can select the display colors to obtain color combinations that give the
best visual contrast.
Data for the program can consist of experimental measurements read from a
disk file, or user can examine any of a library of common mathematical
functions. The library functions now include the six trigonometric functions,
common and natural logarithms, exponential functions, and polynomials. The
purpose of the library of functions is to give visually impaired students the
opportunity to become familiar with the properties of functions that are
encountered frequently in science and engineering.
Other features of the program include a help menu, a menu of operations
that can be performed on the data, and a math toolbox. The toolbox includes a
simple statistical package and tools for the pre-treatment of the data. The
operations that can be performed on the data include taking the first
derivative, the integral, the absolute value, the reciprocal, and natural or
common logs; these operations will enable visually impaired students to
examine, for example, semilog or log-log plots of data.
This is a large and complex program (about 4500 lines of Pascal) and it
still has some bugs in it. After it is thoroughly debugged and tested we plan
to make it available on the networks and to give it the widest possible
dissemination. (I would be delighted to hear from anybody who would be
interested in test driving any of our programs.)
The original version of the program was written in FORTRAN by Margaret
Cetera Gemperline for auditory analysis of spectra and chromatograms. Rosa
McMillan and I translated the functions of Ms. Gemperline's program into Turbo
Pascal, adapted it to run on an IBM-compatible PC, and added large text,
magnified graphics, and other features. The original program was called the
Data Review Program; we call its offspring (naturally) Daughter of Data
Review.
The talking lab station was originally conceived primarily for students
in middle and high schools, but we have been awarded 3-year grant by the
National Science Foundation to write and adapt programs for it intended
specifically to make college chemistry labs more accessible to visually
impaired students. This software will include programs for performing
titrations, infrared and visible spectrometry, gas chromatography, and high-
performance liquid chromatography. Margaret Gemperline (author of the
original auditory data analysis program) is working on this project as a half-
time research associate.
Angelo Morris, a blind graduate student in East Carolina's Department of
Rehabilitation Studies, joined the group on February 1, 1994; Mr. Morris is an
expert on assistive technology for visually impaired people. He will maintain
records on a lending library of adaptive science materials that we are
assembling, and will also evaluate our computer programs.
Acknowledgment: This work is supported by grants from the National Science
Foundation's Directorate of Education and Human Resources. This article is
reproduced by permission from _The Student Advocate_, Volume XII, Number III,
April, 1994. (Published by the National Alliance of Blind Students, David
Sass, editor.)
This archive was generated by hypermail 2b29 : Sun Dec 02 2012 - 01:30:03 PST