  Visible Light Communication (VLC) is emerging as a means to network computing
devices that ameliorates many hurdles of radio-frequency (RF) communications,
for example, the limited available spectrum. Enabling VLC in wearable
computing, however, is challenging because mobility induces unpredictable
drastic changes in light conditions, for example, due to reflective surfaces
and obstacles casting shadows. We experimentally demonstrate that such changes
are so extreme that no single design of a VLC receiver can provide efficient
performance across the board. The diversity found in current wearable devices
complicates matters. Based on these observations, we present three different
designs of VLC receivers that i) are individually orders of magnitude more
efficient than the state-of-the-art in a subset of the possible conditions, and
i) can be combined in a single unit that dynamically switches to the best
performing receiver based on the light conditions. Our evaluation indicates
that dynamic switching incurs minimal overhead, that we can obtain throughput
in the order of MBit/s, and at energy costs lower than many RF devices.
