Abstract: In an arrangement of lighting devices (10), a remote control device (30) and a central control device (20), a particular lighting device to be controlled by means of the remote control device may be selected by a user transmitting a selecting command (42, 43). When the central control device receives the selecting command (44), it carries out a selection sequence (45) during which it controls the lighting devices in one or the other sequence so as to have their output change temporarily (45, 46, 47). If the remote control device, which is directed to the particular lighting device (41), senses such an output change (50), it transmits data representing such an event (51) to the central control device. When the central control device receives such event data (52), it determines the particular lighting device as that to which the remote control device is directed (53) for subsequent control (54) of this particular lighting device.

Abstract: In order to avoid firstly decidedly periodic loading of an output-buffered constant current power supply unit (17) and secondly physiological loading as a result of only intermittently appearing primary colors (R, G, B) when activating mixed light color loci, primary color light sources (11R, 11G, 11B) are energized in pulse-width-modulated fashion periodically in a temporally offset manner, but in addition in each instance, in time-parallel fashion with respect thereto, also those primary color light sources of further primary color light sources (11R, 11G, 11B) whose primary colors in the cyclic activation are not being energized at that time are likewise energized in a pulse-width-modulated manner (FIG. 2).

Abstract: A solid state lighting apparatus includes a plurality of light emitting diodes, a sensor configured to output a sensor signal indicative of at least one operating condition of the solid state lighting apparatus, and a control circuit coupled to the sensor. The control circuit is configured to temporarily interrupt electrical current to ones of the plurality of light emitting diodes at respective intervals responsive to the sensor signal indicating that the operating condition does not meet a desired operating threshold to provide a visible indicator thereof in light emitted by the apparatus. Related devices and methods of operation are also discussed.

Abstract: A light assembly comprising a globe, an electric grid powered lighting element disposed within the globe, a solar powered lighting element disposed within the globe, a solar panel coupled to the solar powered lighting element for collecting light and generating power for the solar powered lighting element, a rechargeable power source coupled to the solar panel and the solar powered lighting element for storing the power generated by the solar panel and powering the solar powered lighting element, a first sensor for detecting an ambient light level and activating the solar powered lighting element when the ambient light level is below a desired ambient light level, and, a second sensor for detecting output levels of the solar powered lighting element and activating the electric grid powered lighting element when the output level of the solar powered lighting element is below a desired output level.

Abstract: A flat display device is adapted for human eye observation with or without applying a NVIS (Night Vision Imaging System). The flat display device includes a display panel, a backlight module and a backlight driving unit. The backlight module includes multiple red light LEDs (Light Emitting Diodes), green light LEDs and blue light LEDs that form together a light source array, so as to generate a backlight by mixing and projecting the red light, green light and blue light to the display panel. The backlight driving unit is electrically connected with the light source array and used to drive and control the red light LEDs, green light LEDs and blue light LEDs. At a night-vision mode, the backlight driving unit may, upon actuation of a actuating signal, adjust or disable the red light LED by for example decreasing or turning off the driving electricity sent to the red light LED, thereby achieving the requirements for nigh vision purposes.

Abstract: A table lamp for protecting eyes includes a base and an illuminator extended from the base. The illuminator includes a sensation controlling module, multiple white LEDs respectively electrically connected to the sensation controlling module, and multiple RGB LED sets respectively electrically connected to the sensation controlling module. The sensation controlling module automatically detects an environmental illumination and an environmental color temperature. The sensation controlling module automatically adjusts an integrated illumination and an integrated color temperature of the illuminator for coordinating to different environments.

Abstract: A load control device for controlling the power delivered to an electrical load has a power switch, a transmitter and/or a receiver in communication with a controller for the switch; a mounting yoke for a traditional style faceplate; an actuator button extending through an opening of the faceplate; an antenna receiving a first signal from a remote control device and/or transmitting a second signal to a remote control device, the receiver coupling the first signal from the antenna to the controller for controlling the switch, the transmitter coupling the second signal from the controller to the antenna. The antenna has a printed circuit board disposed perpendicular to the yoke; first and second magnetically coupled conductive loops; the antenna disposed inside and behind the actuator button and extending through and beyond the opening of the faceplate.

Abstract: In at least one embodiment, brightness multiple LEDs is adjusted by modifying power to subgroups of the multiple LEDs during different times and detecting the brightness of the LEDs during the reductions of power. In at least one embodiment, once the brightness of the LEDs are determined, a controller determines if the brightness meet target brightness values, and, if not, the controller adjusts each LED with the goal meet the target brightness values. In at least one embodiment, a process of modifying power to the subgroups of multiple LEDs over time and adjusting the brightness of the LEDs is referred as “time division and light output sensing and adjusting. Thus, in at least one embodiment, a lighting system includes time division light output sensing and adjustment for different spectrum light emitting diodes (LEDs).

Abstract: A flowerpot including structure for illuminating a plant or other object or objects contained within the flowerpot may comprise a container. At least one light is supported on the container. A power source is coupled to the at least one light. The container may define an upper circumferential rim. The at least one light may be supported proximate the upper circumferential rim. If desired, a plurality of lights may be disposed at spaced intervals about the circumferential rim.

Abstract: A LED lighting assembly comprising at least one LED; the at least one LED being mounted to a support; at least one solar element for creating electric power from solar power; at least one battery for storing electricity generated by the solar element; at least one wind vane operatively associated with the support; at least one motor/generator having a first mode for generating electric power from the wind turbine; and at least one shaft operatively connected to the at least one motor/generator and the support; the motor/generator having a second mode in which the motor/generator operates to rotate the support; the at least one motor/generator being operatively connected to the at least one battery for storing electric power therein.

Abstract: A light source detection and control system applied to a backlight module is provided. The system includes a liquid crystal display (LCD) panel, a plurality of light guide panels, a plurality of anisotropic transmission media, a photo detector (PD), and a controller. The LCD panel is divided into multiple blocks, each including white or RGB light sources. The light guide panels are disposed on the blocks for collecting and guiding the light emitted by the light sources. The anisotropic transmission media are connected to the light guide panels for transmitting the light emitted by the light sources. The PD is connected to the anisotropic transmission media for receiving the light and detecting the luminance of the light emitted by the light sources. The controller is coupled to the PD for adjusting the luminance or color shift of the light sources according to the luminance detected by the PD.

Abstract: A method and system provide for dynamic control of backlighting of a light-transmissive bezel of a display device. A color control signal is received and processed by a processor and control element of the display device to generate a backlighting control signal and transmit the backlighting control signal to the backlighting element of the display device. The backlighting element generates a backlighting color to illuminate the light-transmissive bezel in accordance with the received backlighting control signal; the backlighting control signal adaptively controls the type and the duration of the backlighting color as determined by the color control signal received by the processor and control element.

Abstract: There are provided a light sensor, a display apparatus including the same, and a control method thereof. The display apparatus includes: a display panel which includes a display area through which an image is displayed and a non-display area. A light receiving transistor which is formed in the non-display area and receives outside light. A charging part which includes a first terminal is connected to a drain electrode of the light receiving part and a second terminal is connected to a direct current voltage terminal. A signal amplifying part which includes a first terminal and a second terminal which is connected to a source of reference voltage and receives a reference voltage. A charging switching part is connected between the first input terminal and the first terminal of the charging part. A controller is provided which controls the charging switching part according to a predetermined first cycle to charge or discharge the charging part.

Abstract: A power supply system including a first power supply, a second power supply, a switch board, a relay device, and a control device is provided. The switch board is electrically connected to the first power supply, and the relay device is electrically connected to the switch board. The relay device includes a first solid state relay and a second solid state relay, which are electrically connected to the first power supply and the second power supply respectively. The control device includes a control unit and a first power line communication unit (PLC unit), in which the control unit is electrically connected to the second power supply, and the first PLC unit is electrically connected between the relay device and the second power supply, and the first PLC unit is electrically connected to the control unit.

Abstract: In one aspect, the present invention is directed to an electric appliance control for turning off an electric appliance operating in an indoor space, the electric appliance control comprising: a light sensor, for continuously sensing the light intensity in the indoor space; a fall detector, for detecting a fall in the light intensity sensed by the light sensor, wherein the fall being a negative relative change in light intensity during a period of hundredths of second; a switch, for disconnecting the electrical power supply to the electric appliance; and a control unit, for activating the switch to disconnect the power supply upon detecting a fall in light intensity by the fall detector.

Abstract: A tanning apparatus for radiation treatment for personal care includes at least one gas discharge UV lamp, at least one ballast connected in series with said at least one gas discharge lamp, and at least one incandescent lamp separate from the gas discharge lamp or lamps. The weight of the inductive ballast is reduced in that the incandescent lamp(s) is included in the ballast or ballasts(s).

Abstract: A brightness-adjustable illumination device includes at least two electric lamps and a control module electronically connected to the at least two electric lamps for controlling the lamps on and off. The control module obtains brightness of local environment of the lamps, and controls the number of the lamps turned on according to the brightness of the local environment. A brightness-adjustable illumination system is also disclosed.

Abstract: An easily deployable miniature, LED light unit specifically for home security yard signs that is rechargeable by means of a solar cell array having a light sensor which automatically activates the light at dusk and deactivates it at dawn. The solar light unit is contained in a unique compact molded housing that positions the components and also includes an integral clamp-mount specifically for slide-on mounting to the stakes of typical home security signs.

Abstract: A door mounted dispenser for a refrigerator includes rear and opposing side walls that collectively define a cavity, a release mechanism for dispensing ice and/or water and a light for illuminating the cavity. The cavity light can be operated in one of three distinct modes, i.e., in a first mode wherein the cavity light is continuously illuminated, in a second mode wherein the cavity light is illuminated only through activation of the release mechanism, and in a third mode wherein the cavity light is illuminated based upon a sensed level of ambient light present at or near the refrigerator. In the third mode, the cavity light is illuminated at a first level based upon ambient light and a second, higher level when the release mechanism is operated. The level of ambient light necessary to activate the cavity light can be set by a consumer through control panel inputs.

Abstract: A utility light is provided. The utility light comprises a first array of light sources having a first color facing in a first direction, a second array of light sources having a second color facing in a second direction that substantially opposes the first direction, a motion sensor, and an electronic controller to determine a first state based on an input received from the motion sensor, to operate the first array of light sources in the first state, to determine a second state based on the input received from the motion sensor, and to operate the second array of light sources in the second state.

Abstract: A load control device for controlling the power delivered to an electrical load, the load control device comprising a controllably conductive device for controlling the power delivered to the electrical load, the controllably conductive device having a control input; a controller coupled to the control input of the controllably conductive device for control of the controllably conductive device; a transmitter and/or a receiver in communication with the controller; a substantially-planar mounting yoke adapted to receive a traditional-style faceplate mounted thereto; an actuator button for providing an input to the controller, the actuator button mounted relative to the yoke, such that the actuator button is adapted to extend through an opening of the traditional-style faceplate when the faceplate is attached to the yoke; and an antenna coupled to the transmitter and/or receiver, the antenna adapted to receive a first signal at a specified frequency from a remote control device and/or transmit a second signal a

Abstract: The present invention relates to an artificial solar light system, and more particularly, to an artificial solar light system using light emitting diodes. The present invention can provide an artificial solar light system using light emitting diodes, which can represent the same light emission effects as the sun with time. Further, the present invention can provide an artificial solar light system using light emitting diodes, which is inexpensive and is not affected by positions or climate.

Abstract: A system and method for targeted, remote switching of electrical appliances. The system includes a transmitter for selectively producing a directional output signal and a receiver for detecting the directional output signal from the transmitter. The receiver produces an output signal when the directional output signal from the transmitter is detected that is received by a microcontroller that is incorporated into a switch controller. The microcontroller produces an output that switches the electrical appliance to which the switch controller is connected on and/or off. A coordinator is provided for communicating functional information to and from the switch controller(s) of a plurality of electrical appliances for increased flexibility of operation and control.

Abstract: A system for dimming one or more light sources includes a first light source that emits a light of a first brightness according to an operating condition of the first light source, a second light source that emits a light of a second brightness according to an operating current of the second light source, wherein the light of the first brightness is different than that of the light of the second brightness, and one or more components that references the operating condition of the first light source, wherein, in response to the referenced operating condition of the first light source, the one or more components modifies the operating current of the second light source to substantially match the light of the second brightness to the light of the first brightness. A method for dimming one or more light sources is also disclosed.

Abstract: A lighting and control system is described. One embodiment of the lighting and control system includes a lighting node and a controller. The lighting node may include a light emitting diode configured for illumination and further configured for optical communication with the controller, a node radio device configured for radio communication with the controller, and a node memory configured to store a node identifier and a group identifier. The controller may include an optical sensor configured to sense illumination of the lighting node and further configured for optical communication with the lighting node, a controller radio device configured for radio communication with the lighting node, and a controller memory configured to store a group identifier. The lighting node and the controller may each further include a power supply and a processor. In one embodiment, the lighting node and the controller belong to a wireless mesh network.

Abstract: The invention relates to a marking system comprising lighting devices, for example LEDs (11), that are used on a sport area (1) to indicate demarcations (100) of different games. By activating the associated lighting devices (11), the demarcations (100) of a particular game can selectively be made visible. The marking system may further comprise detection devices that can detect the occurrence of certain game events. Thus photodetectors (12) may for example detect if a ball (2) crosses a demarcation (100). A controller (13) may then activate the lighting devices (11) or separate signaling devices (14, 15) to indicate the detected event. The controller (13) may further communicate wirelessly with persons on the sport area, particularly with the referee to assist his/her decisions.

Abstract: A light generating part generates a first light based on a first control signal. A first driving part outputs a panel driving signal. A display panel receives the first light or a second light that is provided from an exterior to display an image based on the panel driving signal. A sensing part outputs a sensing signal based on the second light. A second driving part compares a reference voltage range with the sensing signal to output the first control signal. The reference voltage range is determined by a first reference voltage and a second reference voltage. Therefore, the light generating part is turned on/off based on the second light to decrease the power consumption of the light generating part, and an operation of the light generating part is stabilized.

Abstract: An apparatus and its corresponding method for switching a light source are provided. The apparatus includes a light sensor, a decision device and a light source. The light sensor senses the ambient luminance and outputs a sensing signal to indicate whether the luminance is greater than a predetermined quantity. The decision device is connected to the light sensor. It receives a switching signal and outputs a lighting signal according to the sensing signal and the switching signal. The light source is coupled to the decision device and is activated whenever the lighting signal demands light.

Abstract: A backlight assembly, a method of driving the same, and a liquid crystal display (LCD) having the same includes a backlight assembly having first and second lamps, a power source for providing power, a sensor for outputting a sensing signal in accordance with the ambient luminance, a power controller for changing the level of the output power of the power source to provide the changed output power to the second lamp in response to the sensing signal, a feedback signal generator for generating a feedback signal as the power of the power source is supplied to the second lamp, and a power converter for providing the power of the power source to the first lamp or changing the level of the output power of the power source to provide the changed output power to the first lamp.

Abstract: An ambient light sensor circuit and a flat panel display device having same that can automatically control screen brightness by sensing ambient brightness and controlling an output current.

Abstract: According to one embodiment, a light emitting portion of a backlight control unit is a direct lighting type. Accordingly, a light emission intensity of all over the light emitting portion cannot be measured by disposing an optical sensor at a portion as a conventional way. However, in the backlight control unit, a light emission control with high accuracy is realized while suppressing a variation between areas on a basis of a measurement of the light emission intensity of all over the light emitting portion, because an optical sensor detects each light source, a measuring device measures the light emitting intensity thereof, and a backlight control portion performs a control of the light emission intensity of each light source based on a measurement result of the measuring device.

Abstract: A method and device for automatically switching on and/or off the illumination of a vehicle. Faulty switching is reduced by adapting the threshold value for switching on the illumination by averaging the measured brightness value(s) according to the driving speed and using switching-off conditions which, inter alia, consider the surrounding brightness.

Abstract: An energy-saving lighting control system for controlling a series of banks of lights in an area. The system activates less than all of the series of banks of lights upon entry into the area, regardless of the last light-activating setting selected by a user.

Abstract: The invention described herein represents a significant improvement in the art of headlights for vehicles. A first element is provided as a means for sensing the presence and location of other motor vehicles, said means for sensing connected to processing and light controlling circuitry such that the electrical current supplied to each element in an array of elements is individually controlled. The result is a headlight system which produces high beams in areas where no vehicle is present and concurrently produces low beams in areas where vehicles are present. In a first embodiment, individual light elements in array are individually controlled with regard to intensity to provide dim beam areas and high beam areas concurrently. In a second embodiment, individual electro-chromatic elements in array are individually controlled so as to provide a means to create dim beam areas and high beam areas concurrently.

Abstract: For a plasma accelerator arrangement in particular for use as an ion thruster in a spacecraft, a structure is proposed in connection with which an accelerated electron beam is admitted into an ionization chamber with fuel gas, and is guided through the ionization chamber in the form of a focused beam against an electric deceleration field, said electric deceleration field acting at the same time as an acceleration field for the fuel ions produced by ionization. The arrangement generates a focused beam of a largely neutral plasma with a high degree of efficiency. Configurations for electric and magnetic fields for guiding and focusing the beams are given by way of example.

Abstract: The disclosed safety light is designed to provide automatic operation for lights placed on elastic tires. Wheel (100) comprises a hub (84), a urethane tire (88), and a safety light circuit molded into the urethane tire and hub. The safety light circuit is formed on a circuit board which holds electrical components comprising, a battery (B1), deformation-activated switch (SW1), photo sensor and delay(CDS1, D1, R1, R2, Q1, C1), and illumination devices (LED1 and LED2). Battery(B1) provides electromotive power to operate all circuitry, with switch (SW1), photo sensor CDS1, and illumination devices (LEDp1 and LED2) placed substantially in series electrically. Switch (SW1) is designed to conduct current when a change in deformation or a specified rate-of-change in deformation of the tire material is detected. The photocell (CDS1) signals the photo-sensor to conduct current when photocell (CDS1) detects a sufficiently low level of light.

Abstract: An electronic ballast for at least one low-pressure discharge lamp contains an inverter which is connected to a direct-voltage source (UBUS), a load circuit which is connected to the inverter and contains the lamp (LA) and a series resonant circuit, and an evaluating circuit arrangement (M1) which reacts to different operating states of the lamp (LA) and in the case of a defect or removal of the lamp (LA) generates corresponding signals which are used to switch off the inverter. Provided for the purpose of heating the coils (W1, W2) there is a heating transformer, the primary winding (Tp) of which is connected in series with a switch (S3) to the output of the inverter and in any case is connected to the direct-voltage source (UBUS) if the inverter is switched off on account of the heating-coil defect or the removal of the lamp (LA), with the switch (S3) being clocked in this off-phase.

Abstract: The present invention provides a control apparatus (11) for controlling luminescence produced by a light source (12) which includes a sensor (17) for sensing motion of air and a circuit (3) for varying the luminescence provided by the light source when motion of air is sensed. The sensor (17) is an air pressure sensor and all changes in the luminescence provided by the light source (12) are occasioned by sensed changes in air pressure. The present invention also provides lighting apparatus (10, 11, 12) which includes the control apparatus (11).

Abstract: A light level sensor for use in controlling the switching of artificial lighting. The sensor comprises a photoelectric transducer which provides an output signal at a level which is significant of the illumination level of incident light. An A-D converter and a microprocessor are located in circuit with the transducer for detecting the level of the transducer output signal and for any cyclic variation of the transducer output signal resulting from cyclic variation of the level of incident light. Further circuit means are provided for generating a sensor output signal if either (a) the level of the transducer output signal is below a predetermined level or (b) the level of the output signal is above the predetermined level and, at the same time, cyclic variations occur in the level of the transducer output signal.

Abstract: A lighting system having at least one light source for supplying artificial light and a control unit for controlling the light source. The light source is of the type having an adjustable color temperature. The control unit is provided with a control signal form a signal from a signal generator. The signal generator is dependent on the mean daylight level. The control unit is arranged to adjust the color temperature of the light source in dependence on a predetermined relationship between the mean daylight level and the color temperature of the artificial light. The lighting system will provide artificial light which will when the daylight level, as measured on an office desk, increases from approximately 400 lux to approximately 800 lux, increase the color temperature from approximately 3300 K to approximately 4300 K.

Abstract: A back-up power system for a portable table lamp which accommodates a standard replaceable compact fluorescent bulb that is illuminated from an AC main power source when AC house current is available and is illuminated by a DC to DC converter when AC house current is unavailable, the converter being powered by replaceable low voltage battery located in the base of the lamp and charged by the AC source, with the loss of AC house current being sensed to cause the disconnection of the AC house current source and connection to the low voltage replaceable battery.

Abstract: A lighting system having at least one light source for supplying artificial light and a control unit for controlling the light source. The light source is of the type having an adjustable color temperature. The control unit is provided with a control signal from a signal generator. The signal generator is dependent on the mean daylight level. The control unit is arranged to adjust the color temperature of the light source in dependence on a predetermined relationship between the mean daylight level and the color temperature of the artificial light. The lighting system will provide artificial light which will when the daylight level, as measured on an office desk, increases from approximately 400 lux to approximately 800 lux, increase the color temperature from approximately 3300 K to approximately 4300 K.

Abstract: An ignition activated automotive headlight system having a high beam circuit and a low beam circuit, the low beam circuit having a resistor in series connection therewith for daylight driving, the low beam circuit further having a photoelectrically operated by-pass circuit around the resistor, thereby permitting normal operation of the low beam circuit for nighttime driving.

Abstract: A device for controlling power to an electrical load. The device has two components: a portable desktop detector unit and an electrical powerstrip. The desktop detector detects the presence of a human in a room and sends signals to the powerstrip to supply power to or withhold power from individual electrical loads connected to the strip. Since the detector is portable, it can be positioned and repositioned at different locations in a room to maximize its ability to detect the presence of a person. The system can also communicate by wireless signals to a wall-mounted control unit to control light fixtures in the room. When used with a wall-mounted control unit, a photo sensor that detects the level of ambient light in a room allows the system to adjust the brightness of lights in the room depending upon the available ambient light level.

Abstract: An electronic flash device having a slave emission function and a standby mode, includes a setting member for setting the slave emission function, activation means activated in response to an input generated upon the function setting operation of the setting member, and power supply control means for controlling a power supply of the electronic flash device to be turned on based on the activation of the activation means.

Abstract: A system for controlling the intensity of a lamp including a remote sensing device for detecting the presence of an occupant within an area. The device also transmits a signal based on the currently sensed presence of the occupant. After each transmission of an occupancy signal, the device is inhibited from further transmission for a first predetermined period of time to limit power consumption requirements by the battery powered device. The system also includes a light controller responsive to the transmitted occupancy signal for controlling the level of illumination by the lamp. In the absence of a transmitted occupancy signal within a second predetermined period of time, the light controller will instruct the ballast to reduce the level of illumination by the lamp. In the absence of an occupancy signal being transmitted within a third predetermined time period, the light controller will instruct the ballast to turn off the lamp.

Abstract: A lighting apparatus has a secondary battery, at least two light emitters connected in parallel with each other, first switches, and second switches. When the first switches are each ON, i.e., closed and the second switches are each OFF, i.e., open, the light emitters are connected in parallel with each other and in series with the secondary battery. When the first switches are each OFF and the second switches are each ON, the light emitters and secondary battery are connected in series.

Abstract: A processor controlled fluorescent lamp dimmer circuit is shown for use in an aircraft display system utilizing a fluorescent lamp in the backlight system of individual LCD display devices. By use of a processor control dimming circuit in control over each LCD display, greater flexibility, e.g., as by adjustment in software parameters, is made possible in the operation of a dimmer control circuit. The dimmer control circuit reacts to such conditions as ambient light within the aircraft cockpit, fluorescent lamp light energy output, and fluorescent lamp temperature to provide substantially consistent actual and perceived luminance on the LCD display as a function of such detected conditions. Furthermore, the processor control achieves the desired luminance without over-driving, and therefore deteriorating, the lamps. As a result, the pilot of the aircraft enjoys a more reliable and consistent LCD display and need not be distracted by variation in luminance of the LCD display in operation of the aircraft.

Abstract: Disclosed is a ballast circuit for a high pressure gas discharge lamp, including a comparator circuit for producing a feedback error signal representing the difference between a feedback signal and a reference signal. The feedback signal is selectively one of a non-light feedback signal and a light feedback signal, as determined by a switching circuit. A power control circuit adjusts the level of power supplied to the lamp in response to the feedback error signal. A first, non-light feedback circuit supplies a non-light feedback signal to the comparator circuit, based on non-light information of the lamp that is fed back to the non-light feedback circuit. A light feedback circuit operative during a lamp warm-up period supplies a light feedback signal to the comparator circuit based on light intensity information that is fed back to the light feedback circuit.

Abstract: A fully automatic and energy efficient lighting control or light switch comprises different settings, preset by a user, and activates all or a portion of at least one bank of lights upon detecting occupants within a room. In one embodiment, the light switch detects doppler-shifted, reflected ultrasonic waves caused by occupant motion within the room. In an automatic mode, the light switch is configured to automatically switch from an initial sensitivity level for detecting motion within a short range therefrom, to a higher sensitivity level for detecting motion anywhere within the room. After the room is empty or no motion is sensed, the light switch is configured to turn the lights off following a variable time delay. The light switch returns to its initial low sensitivity level following a predetermined grace period which begins once the lights are turned off.