BioCoder #6

Chapter 7. A Simple Data Acquisition and Plotting System for Low-Cost Experimentation

Jonathan Cline

Abstract

This paper details the design and construction of a simple data acquisition and plotting system for amateur or commercial use. The system uses a general-purpose computer; a standardized, USB-powered peripheral board; and a small software application to measure, record, and plot a real-time signal. The system is demonstrated in use with a biochemistry chromatography experiment; however, the system may be used in conjunction with any experiment that needs to measure and plot an electrical signal. Modifications to the hardware to adapt the circuit to various signal voltages are discussed. Total cost is about $35 in parts, a few hours connecting common electronic components with a soldering iron, and a few hours configuring software on any typical computer. This system does require a separate computer that supports USB, although you can substitute a small, inexpensive embedded computer, such as the popular Raspberry Pi board (currently $25). In contrast, a commercial-grade chart recorder that performs the same functions might have a price tag of $2,000. Building this basic data acquisition system also yields the understanding of how to design such systems and use them either in laboratory protocols or in field experiments.

This paper follows a typical engineering format: laboratory requirements, design considerations, theory of operation, and build instructions. Suggestions ...