Assistive Technology in the Science Laboratory: A Talking Laboratory Work Station for Visually Impaired Science Students
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 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 measurements, 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