A detection field selectable motion sensor that includes a modulator having a output with a shaped response to received radiation emissions forming a detection field and a sensor configured to detect the output from the modulator. The motion sensor can be configured with a set of lenses that can be aligned with the sensor. Further, the motion sensor can be an active sensor that transmits electromagnetic radiation which is detected after reflection from a detection field. Infrared radiation is the preferred source of received and transmitted radiation but microwave or visible light can be used. For an active motion detection either coherent or incoherent radiation can be used. The motion sensor includes a means for mounting and a hinge or swivel for orientating the sensor.