Poster: Battery-free Visible Light Sensing

We present our efforts to design the first Visible Light Sensing (VLS) system that consumes only tens of μ Ws of power to sense and communicate. Our system requires no modification to the existing light infrastructure and uses unmodulated ambient light as sensing medium. We achieve this by designing a sensing mechanism that uses solar cells to achieve sub-μWs of power consumption. Further, we devise an ultra-low power backscatter based transmission mechanism we call Scatterlight that transmits digital readings without incurring the processing and computation overhead of existing sensors. Based on these principles we build a preliminary prototype. Our initial results demonstrate its ability to sense and communicate three hand gestures at 20 μWs of power.