An edge-fed waveguide luminaire includes a light waveguide having a planar body, a waveguide edge support structure, and an anchor opening in the planar body of the light waveguide, which is displaced from said waveguide edge support structure. A sensor is fixed in the anchor opening of said light waveguide so as to be responsive to conditions in the space below the luminaire. The sensor, which will have minimal impact on the aesthetic qualities of the luminaire, is in communication with light switching means for adjusting the light output from the luminaire in response to changes in conditions in the space below the luminaire.