A simple computer interface for studying smooth muscle physiology

One of the best ways for biology students to study the dynamics of smooth muscle physiology is to use a smooth muscle transducer (Harvard Apparatus) which converts the small contractions into a varying voltage. Traditionally, the output of the apparatus is sent to a chart recorder where the data is recorded on chart paper for later analysis. An interface has been designed in which the signals from the Harvard Apparatus are digitized and sent to a computer for display and analysis. The hardware design consists of an Analog to Digital Converter interfaced to an IBM compatible computer through a printer port. The cost of this interfacing hardware, including the printer port, is approximately thirty dollars. The software is a short program which controls the interface and allows the display of the smooth muscle contractions as a function of time on the computer screen. The program can also create a data file for future display and analysis, and can mimic the chart recorder output by printing the graph to a printer. This system has several advantages compared to using a chart recorder. The computer interfaced experiment allows for paperless data collection and display. The data may be exported to other programs (spreadsheets or graphing software) for further manipulation and analysis. Finally, it exposes the biology student to computer technology for data collection and analysis.