Methods and systems for providing a light device that can emit light and sense light are disclosed. In one embodiment, a lighting device includes a light guide having a planar first surface, the light guide configured such that at least some ambient light enters the light guide through the first surface and propagates therein, and at least one light detector disposed along an edge of the light guide, the at least one detector optically coupled to the light guide to receive light propagating therein. The light detector can be configured to produce a control signal. In some embodiments, the lighting device also includes at least one light turning feature disposed on the first surface, the at least one light turning feature configured to direct light incident into the light guide through the first surface.