Towards a Smart Earring for Continuous Heart Rate and Audio Monitoring

The use of smart wearable devices has increased in fields like healthcare or activity tracking in the past few years. However, the conceptualization, design, and integration of multimodal wearable systems needs to be further developed and boosted. Besides being comfortable and discrete, smart wearables need to consider the acquisition of different modalities or sources of information to cope and tackle with upcoming challenges to be performed within the edge-computing context. On this basis, this work proposes a new smart device that includes multimodal acquisition and processing capabilities. Specifically, a smart earring was designed. It consists of a heart rate sensor and two microphones. The objective of this work is twofold, to compare the different microphone technologies integrated within the device, and to test the heart rate measuring viability in the earlobe. Results reported that piezoelectric microphones are a better option since they are hermetic and have a better frequency response when sealed. Moreover, it was proven that heart rate can be successfully measured in the earlobe. This research is intended as a step towards a multimodal and inconspicuous smart device design, which facilitates further work with the development of novel wearable systems and with real-life data acquisition.