Abstract: An occupancy sensor device has a housing with a neck entry affording a light path to a recessed sensor. The interior of the light path has properties of reflection and/or refraction to improve effective field of view of the sensor. A tubular member as the neck can be angularly adjustable for selective electrical connection to a circuit board carrying the sensor and contacts at its end. That board can be clamped in slots in an inner part of the housing. Fitting to a barrier can be aided by clenching action of a spring member apertured to group an outer housing part when relaxed.