Development of a Data Acquisition and Data Analysis System for Visually Impaired Chemistry Students David Lunney East Carolina University Greenville, NC 27858
Chemistry laboratories present major barriers to visually impaired students who want to pursue'careers in the natural sciences or engineering. The purpose of this project is to lower those barriers bv d e v e l o ~ i nsoftware ~ that will make computer-aidedchemistry experiments more accessible to students who havc visual impairments. The software will run on an ordinary personaicomputer equiDed with relatively inexpensive, widely available hardware including adapted outputs (synthetic speech, electronic music, and enlarged text and graphics). Experimental data will be acquired through an IBM Personal Science Laboratory (PSL), a modular data acquisition subsystem designed for use in educational laboratories, a n d through an inexpensive ($130) digital multimeter (DMM) equipped with a serial output port. Several data acquisition systems for educational laboratories are now available. but we chose the IBM PSL because it is an open system and because it is likely to become a de facto standard. The PSL base unit is about the size of a tekbook. The modules, which connect it to its various probes, plug into the side of the base unit and are about the size of a computer mouse. The PSL communicates with a host computer through a standard serial port and reads its probes upon receiving binary commands from the host. The PSL has probes for measurement of pH, temperature, and light intensity (among others). With the addition of an electronic balance, the PSLlDMM system is able to measure mass, time, temperature, pH, AC/DC voltages and currents, resistance, capacitance, and frequency and
308
Journal of Chemical Education
present the readings to the user via large text, speech, and musical sounds. The system is capable of logging data to a disk file for later analysis and includes auditory data analysis programs. One-dimensionaldata arrays can be examined as rising and falling pitches, with spoken values ofthe coordinates of interesting points; more complex data is presented as electronic music, after suitable pre-treatment. We are using Creative Labs Sound Blaster sound cards for output of speech and electronic music. The low end Sound Blaster (with a street price of about $75) has a ninev voice F M music svnthesizer. can record and ~ l a back sounds digitally, ahd has a text-to-speech conv&r that produces intelligible speech. The audio recording (sampler) capability of the Sound Blaster cards makes them useful in data acquisition, also. The Personal Science Laboratory has limited throughput with its standard modules (about 200 Hz); however, the Sound Blaster 16(which costs about $200) can digitize two channels simultaneously at rates up to 44.1 kHz with 16-bit resolution. Amaior advantage ofthe Sound Blaster cards is that they are de facto standards for multimedia systems, so our s o h a r e will run with sound cards made by other manufacturers. Ex~erimentsfor which software is beinz develo~edinclude the instrumental methods commonl$ used ir;lower level chemistry courses: potentiometric titrations, UV-visible and infrared spectroscopy, and gas and liquid chromatography. The system and its software will be usable at any educational level where instrumental measurements are performed and should be readily adaptable to disciplines other than cbemistw. Software ~roducedfor this ~roiect will be distributed &e on the nLworks, and will be a&able from the author. Acknowledgment This project is supported by NSF Grant number DUE9254330.
