A patient monitoring system having a motion detection unit with a sensor and a control unit having control circuitry and at least one light. Wiring extends between the two units and couples a motion sensor with the control circuitry. A door sensor is coupled with the control circuitry. The light is illuminated to provide a silent alarm when motion is detected and the door is closed. Also disclosed is a method of installation that includes attaching a motion detector unit and the control unit to wall surfaces on opposite sides of the door and extending wiring through the doorway to operably couple the two units. The motion sensor may be installed to define a detection zone having a lower boundary which is at least about 18 inches above a patient support surface.