Hapt-Aids: Self-Powered, On-Body Haptics for Activity Monitoring

Wearables are becoming increasingly useful, primarily due to their activity-monitoring features that enable various healthcare applications. Everyday devices like smartwatches, however, often have complex ecosystems and convoluted interfaces. These devices need constant charging and can be difficult to use, cumbersome for users interested in only simple applications. As an alternative, simpler everyday wearable, we present Hapt-Aids, self-powered on-body tags that passively monitor user activities and deliver haptic notifications. Our small-footprint devices 1) harvest energy from activity-specific sources, 2) use this energy as sensor information, and 3) convert this energy into haptic actuation using only analog hardware, without digital components or firmware. This structurally simple, triple-purpose design makes our system extremely low maintenance while being cost- and energy-efficient, leading to a friendly user experience. We present our proof-of-concept system design: a custom, unique architecture formed through theoretical modeling and evaluation studies, and we build four demo applications. Through in-lab benchmark testing and user studies, we demonstrate the potential of Hapt-Aids as alternative low-cost, easy-to-use wearables.