Microcontroller-based Biopotential Data Acquisition Systems: Practical Design Considerations

Abstract

Non-invasive bioimpedance measurements are an important part of routine diagnostic procedures. ECG (Electrocardiograph), EEG (Electroencephalograph), EMG (Electromyography) and EOG (Electrooculograph) measurements are amongst the most common non-invasive measurements used for diagnosis. The advances in microcontroller technology over the past 25 years have resulted in general-purpose, low-cost, low-power devices that can perform many of the operations involved in the measurement, and analysis process. Although the data acquisition system architecture is similar for the different noninvasive biopotential measurements, practical considerations have to be taken into account for each particular biopotential measurement: rate of amplification, filter bandpass frequency, overall bandwidth and Analogue-to-Digital conversion rate. This chapter presents an overview of the electrical characteristics of different biopotential measurements and general data acquisition architecture for portable biopotential measurement equipment. This chapter also addresses the importance of electrical isolation to ensure patient safety while using biopotential measurement equipment. Two case studies are presented: a microcontroller-based EEG data acquisition system for measurement of auditory evoked potentials for diagnosis of hypoacusis and a microcontroller-based ambulatory ECG data acquisition system.