FIELD: physics, control.
SUBSTANCE: device status is controlled by detecting (403) user presence; changing the device status to a first status (405) if user presence is detected within a first given area; changing the device status to a second state (407) if user presence is detected outside a second given area, wherein the first given area is smaller than the second given area and is completely contained in the second given area; and supporting (407) the current device status if user presence is detected outside the first given area and within the second given area.
EFFECT: high efficiency.
11 cl, 7 dwg
