A wearable electrocardiograph as a means to combine measurement and makerspace concepts in a biomedical instrumentation course sequence

Abstract

The medical device industry is experiencing a move toward devices that communicate with cell phones, primarily driven by the desire for lower-cost medical monitoring tools that promote personalized medicine. A concurrent phenomenon is the emergence of makerspace resources that allow individuals, as hobbyists or engineers in training, to prototype technical gadgets with the aid of 3D printers and connectible components - components that would traditionally have been designed from the ground up by a trained engineer but can now be purchased with standardized interfaces and supporting software libraries. This paper describes the initial implementation of a wearable electrocardiograph project for a senior-level undergraduate biomedical instrumentation course sequence at Kansas State University. The project integrated circuit-level design concepts with makerspace tools consistent with the move toward personalized medicine. Each student in the course was tasked with designing a wearable electrocardiograph that communicates with a cell phone via a Bluetooth Low Energy (BLE) link. The student was responsible for the low-level analog circuit design (e.g., differential amplifiers, filters, and single-ended design for battery operation), the digital circuitry (e.g., analog-to-digital conversion), the board layout/population, and the 3D-printed case. Due to time constraints, teaching-assistant help was offered in terms of the BLE data transmission and the cell phone app. Portable data acquisition hardware (Digilent Analog Discovery 2 units) and virtual instrument software (WaveForms 2015 software) provided students with means to build and test circuitry outside of the confines of traditional benchtop laboratories. Student performance was assessed relative to learning objectives specified for the project, and pre/post surveys were employed to gauge student self-perceptions of learning with regard to physical device components, instrumentation concepts, analog circuitry, digital circuitry, wireless links, printed circuit boards, 3D printing, and cell phone apps. While project-completion rates were lower than anticipated, student responses were positive, particularly with regard to skills learned and experiences with new types of engineering tools. Specific lessons learned from this trial project are enumerated. These will guide the project evolution in future course offerings.