A Systematic Study of the Influence of Various User Specific and Environmental Factors on Wearable Human Body Capacitance Sensing

Body capacitance change is an interesting signal for a variety of body sensor network applications in activity recognition. Although many promising applications have been published, capacitive on body sensing is much less understood than more dominant wearable sensing modalities such as IMUs and has been primarily studied in individual, constrained applications. This paper aims to go from such individual-specific application to a systemic analysis of how much the body capacitance is influenced by what type of factors and how does it vary from person to person. The idea is to provide a basic form which other researchers can decide if and in what form capacitive sensing is suitable for their specific applications. To this end, we present a design of a low power, small form factor measurement device and use it to measure the capacitance of the human body in various settings relevant for wearable activity recognition. We also demonstrate on simple examples how those measurements can be translated into use cases such as ground type recognition, exact step counting and gait partitioning.