Chris
Harrison

Sozu: Self-Powered Radio Tags for Building-Scale Activity Sensing

Robust, wide-area sensing of human environments has been a long-standing research goal. We present Sozu, a new low-cost sensing system that can detect a wide range of events wirelessly, through walls and without line of sight, at whole-building scale. To achieve this in a battery-free manner, Sozu tags convert energy from activities that they sense into RF broadcasts, acting like miniature self-powered radio stations. We describe the results from a series of iterative studies, culminating in a deployment study with 30 instrumented objects. Results show that Sozu is very accurate, with true positive event detection exceeding 99%, with almost no false positives. Beyond event detection, we show that Sozu can be extended to detect richer signals, such as the state, intensity, count, and rate of events.

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Reference

Zhang, Y., Iravantchi, Y., Jin, H., Kumar, S. and Harrison, C. 2019. Sozu: Self-Powered Radio Tags for Building-Scale Activity Sensing. In Proceedings of the 32st Annual ACM Symposium on User Interface Software and Technology (New Orleans, USA, October 20 - 23, 2019). UIST '19. ACM, New York, NY.

© Chris Harrison