Designing engaging camera based mobile games for implicit heart rate monitoring

Heart rate monitoring is widely used in clinical care, fitness training, and stress management. However, tracking individuals' heart rate faces two major challenges, namely equipment availability and user motivation. In this paper, we present a novel technique, LivePulse Games (LPG), to measure users' heart rate in real time by having them play casual games on unmodified mobile phones. With LPG, heart rate is calculated by detecting changes in transparency of users' fingertips via a mobile device's built-in camera. More importantly, LPG integrate users' camera lens covering actions as an essential control mechanism for game play, and detect heart rate implicitly from intermittent lens covering actions. We explore the design space and trade-offs of LPG through three rounds of interactive design and report the preliminary results from a 12-subject user study.