Abstract: A system for monitoring the level of light at a distant location from a central location. A light sensor at the location to be monitored is comprised essentially of a photodiode and an operational amplifier and produces a high-level, analog output signal on an output signal line, the signal being linearly proportional to the level of light at the location. A control unit at a central location is electrically coupled to the sensor and comprises a power supply for providing electrical power to the sensor and a calibration device connected to the output signal line for providing a feedback signal to the sensor. The calibration device may be adjusted so that the output signal at the control unit bears a selected ratio to the light detected. A control unit having a single and power supply may be coupled to a plurality of sensors.

Abstract: A composite light pickup device for use in an automotive vehicle to collect light from both the ambient surroundings and from oncoming vehicles and employing separate optical fiber couplings of the collected light to a headlamp system that responsively activates the vehicle headlamps when the ambient light level is too low and switches the activated headlamps between high and low beams in response to receiving light from oncoming vehicle headlamps.

Abstract: A photoelectric transducer element responsive to ambient light and a combination of ambient and projected light from light emitting apparatus operates with a predetermined cycle by signals from an oscillator. This produces respective output signals which are then stored on first and second storing apparatus. Signals from the storing apparatus provide information necessary for photographing, since the storing operation is synchronized with the oscillating operation.

Abstract: A field-adjustable power control arrangement for and method of controlling outdoor lighting systems in accordance with a timing cycle which turns an outdoor lighting system off at dawn, on at dusk, off at a nighttime turn-off time after dusk, and on at a morning turn-on time before dawn. The nighttime turn-off time and the morning turn-on time are manually adjustable in an analog and digital manner so as to permit easy and rapid field adjustment and/or factory pre-adjustment.

Abstract: A power controller for an electronic apparatus including an electrophotographic copying machine is provided for automatically prohibiting power supply to parts of the apparatus in response to the reduction of a light-shining amount, e.g., a decrease in the light surrounding the apparatus. The power controller includes a photosensitive element, a comparator, a delay circuit, a gate, and a relay. The photosensitive element serves to provide a voltage in accordance with the surrounding brightness.

Abstract: A box formed with an aperture in which a photosensitive cell is secured includes an electronic circuit connected to be fed by the electrical signal produced by the photosensitive cell when the latter is irradiated by ambient radiation. Said electronic circuit comprises a delay circuit adapted to receive the signal and arranged to produce a control signal when the cell has been irradiated for a predetermined time interval; an audible signal generator received in the box opposite apertures and connected to produce an audible signal in response to the control signal; and a circuit adapted to interrupt the audible signal after a predetermined time interval so that the audible signal is of predetermined duration.The box has means for securing it to an object which is required not to be lost accidentally, e.g. keys, a wallet, a diary, etc. A cover can be provided for being placed over the cell to protect it and keep away external radiations when the reminder device is not required to be operative.

Abstract: Automatic brightness control apparatus for providing real time control of the brightness of various types of displays while also providing ambient light compensation is disclosed which includes a photodiode for providing a current proportional to the ambient light level. Amplifiers, together with a load, change the photodiode current to a control voltage indicating the level of ambient light. The control voltage is provided as a reference input to a voltage comparator. The other input to the voltage comparator is the output of a free running ramp oscillator. The pulse width modulated logic signal comprising the output of the voltage comparator is provided as the input for an output driver whose pulse stream output is used to control the brightness of the designated display. The duty cycle of the pulse stream output varies with the ambient light level.

Abstract: An illumination control device controls the level of artificial lighting depending upon the intensity of natural light in the area being controlled. A single adjustment is used to set the switching point at which the illumination control device becomes operative. An indicator is provided to indicate the adjustment status before a change in the artificial light condition occurs. A filter is employed to produce turn-on and turn-off time delays which differ from one another and are automatically changed in accordance with the instantaneous light level which exists prior to a necessary circuit switching operation.

Abstract: A lamp dimmer control utilizing a variable resistor and an associated adjustment mechanism having an ambient light sensor mounted integral to the control so as to receive ambient light external to the control housing via a translucent adjustment mechanism. Constant contrast illumination control is achieved by pulse width modulation techniques in accordance with the output of the variable resistance setting and the output of the ambient light sensor.

Abstract: An energy conserving circuit for controlling supply of electrical power to various loads such as a street lamp or a hot water heater comprises a photoelectric device for starting a timer when a change from daylight to dark is sensed at sundown, and a load power control responsive to the timer to switch between power-off and power-on states. With a street lamp the timer and power control means are connected to switch the power control means to power-on state at the beginning of the delay period at sundown and later, well before sunrise, to switch to power-off state. In the case of a household hot water heater the switching of the power control to power-on state is delayed until the peak demand hours have ended after sundown. The photoelectric device will normally cause the power control to switch to power-off state at sunrise.

Abstract: A lighting feedback control system for applying AC power to at least one lamp, which includes a conduction angle controlled phase switching circuit connected in series with the lamp and an AC power source for switching power across the lamp, and a line switching circuit for enabling the application of AC power to the lamp through the phase switching circuit. A light sensor is provided for generating a light control signal indicative of the amount of ambient light present in the predetermined location. Coupled to the light sensing circuit is a phase angle conduction control circuit which generates and applies to a control terminal of the phase switching circuit a phase control signal to control the phase angle conduction time of the phase switching circuit based on the amount of ambient light measured by the light sensing circuit to maintain a constant level of lighting.

Abstract: A power supply for a light emitting diode (2) is governed by two photo diodes (6,7) each arranged to act upon the base of one of two transistors (3,4) in a darlington connection. One photo diode (6) is adapted to be influenced by low intensity light, whereas the other diode (7) is adapted to be influenced by light of higher intensity.

Abstract: A solar recharged power supply circuit for a lighting system which circuit includes a rechargeable power source, a solar powered recharger connected to that rechargeable power source and which circuit prevents discharge of that rechargeable power source through the solar powered recharger during times when the recharger is inactive; prevents overcharging of that power source; prevents discharging that power source below a predetermined level; and automatically connects and disconnects the lighting system to and from the rechargeable power source.

Abstract: A battery-operated smoke alarm includes an alerting signal means for indicating when the battery voltage is low by comparing a first signal which is a function of the battery output voltage with a relatively fixed reference signal and producing an alerting signal when the first signal is less than the reference signal. Means are provided for squelching the low battery voltage alerting signal for the first several nights after the onset of the low battery voltage condition by incorporating photosensitive means in the generating circuit for either the first signal or the reference signal for shifting the level of that signal away from the other signal under dark conditions.

Abstract: A system and method for providing substantially constant visibility over a ask area within a work area with time in which the visibility provided by natural daylight illumination is supplemented by a variable artificial illumination from luminaires to maintain a specified visibility. The background luminance and the difference luminance are determined as a function of the artificial illumination and the natural daylight. These relationships are used to determine the actual visibility at the task. The actual visibility is then compared with a criterion visibility and the intensity of the artificial illumination from the luminaires is varied to bring the actual visibility to the criterion visibility.

Abstract: Solar illuminating compensating apparatus is disclosed whereby the interior of a building is illuminated to a substantially constant, predetermined level of light intensity by a combination of natural illumination from the sun and artificial illumination from electricity wherein the intensity of said artificial illumination is controlled by fully electronic means which increases the level of artificial illumination when the natural illumination is inadequate and vice versa.

Abstract: A sunlight collector, containing a Fresnel lens, is mounted on the roof of a building and tracks the sun during daylight hours. A concentrated beam of sunlight is directed through a light transmission channel to locations within the building where the light is distributed. The transmission channel utilizes a focusing lens for further concentrating the solar beam, refocusing lenses for correcting divergences in the beam, reflectors for redirecting the beam, and beam splitters for distributing the beam into light fixtures located throughout the interior of the building. The light fixtures contain filters for controlling the intensity and spectral content of the incoming beam, and optical elements for dispersing the beam. Additionally, the fixture contains rigidly mounted fluorescent tubes, providing artificial light, which are automatically energized when the solar light is insufficient for lighting purposes.

Abstract: A light-responsive control circuit for the purpose of connecting a load, generally an electric lamp, to an AC source every evening at dusk and disconnecting the load from the AC source later each night at a solar time established by the setting of timepiece-like controls, all without the need for user synchronization of included timekeeping circuitry with the time of day. Starting at dawn each day, a light-responsive switch causes a counter to measure the passage of time by accumulating a count representing one-half hour for each hour that passes, by counting alternations of the AC source voltage. At dusk the count approximately represents the number of hours that have elapsed since solar noon and at that time the light-responsive switch causes the load to be switched on and also causes a signal having a frequency double that of the AC source voltage to be applied to the counter to maintain a correct representation of the solar time of day.

Abstract: In an area illuminated by both artificial and natural light sources, a control system is implemented to reduce the energy consumption by proportionately dimming the artificial sources to a level such that the sum of natural plus artificial light is held essentially constant. Use of an open loop sensing scheme allows the control system to operate over a wide range of conditions with no oscillations and good control of the total illumination level.

Abstract: This invention relates to an automatic lighting control system which employs a photosensitive detector in one leg of a bridge circuit for sensing the total effective level of both the natural and artificial illumination within an interior space. The unbalanced output of the bridge is fed into a pair of differential comparators for deriving a digital error signal representative of the level of illumination falling outside an acceptable range. A digital error signal is loaded into an intermediate shift register responsive to a clock signal. If an error signal of the type requiring a change in illumination is present, then a subsequent clock pulse will command a shift register to add or interrupt power to one or more lighting modules which supply artificial illumination to the interior space.

Abstract: A lighting system for illuminating a given area is disclosed herein and includes a number of luminaires, each having a light source and a light sensitive device for automatically connecting the light source to a supply of power during the dark hours of the night and for automatically disconnecting the light source during the light hours of the day. This system also includes light control circuits associated with some but preferably not all of the luminaires. Each light control circuit overrides the operation of an associated light sensitive device and automatically disconnects its light source from the power supply for a predetermined period during the dark hours at a time when it is not important to provide a high degree of illumination, for example in the middle of the night.

Abstract: A lamp control circuit having a heater and thermistor coupled between the illumination sensitive device and the control electrode of an SCR or triac for providing a time delay between the detection of a change in illumination and the switching of the SCR or triac.

Abstract: A photodetector timer network for controlling the timing of application of electrical power to an electrical load responsive to ambient light conditions and including photodetector means for detecting the ambient light and generating a detector signal responsive thereto, means responsive to the detector signal for controlling electrical power from an external electrical source to an external electrical load and means for interrupting the electrical power to the electrical load at certain time intervals.

Abstract: A switching arrangement for the control of an adjustable member such as a valve includes a light sensitive switch. Detection of a particular light value enables a frequency divider to transmit an opening pulse to a valve control circuit a predetermined delay period after the detection of such light value. The frequency of an output signal of a pulse generator is varied in response to the opening pulse and the frequency divider transmits a closing pulse to the control circuit after a second predetermined time period of different duration from the delay period. In one disclosed embodiment, control of the frequency divider is responsive to moisture content of soil as well as ambient light level for application in automatic sprinkler systems.

Abstract: The disclosure is of a light-responsive electric switch which is characterized in that it is constituted mainly by a photoresistive cell inserted in a voltage-divider bridge of which the voltage variations, as functions of the illumination, control a standard integrated circuit comprising four NAND gates which, through the intermediary of a transistor, actuate a triac controlling the illumination circuit.

Abstract: A combination electric lamp dimmer with automatic photocontrol which is adapted for mounting within a conventional electrical junction box such as mounted within walls. The devices includes a rotary dimmer switch for adjusting the current magnitude provided to the lamp to establish the magnitude of light produced thereby. The position of the dimmer switch is controlled by a manually rotatable knob. The knob includes an opening in it to allow ambient light to pass therethrough. A photocell is mounted behind the knob. When a knob is rotated to a position wherein the opening is disposed over the photocell, the photocell is enabled to monitor the ambient light. When the ambient light intensity drops below a predetermined value, the photocell and switch means responsive thereto enable current to be provided through the dimmer to the lamp to illuminate it.

Abstract: Illumination control apparatus for supplementing light from solar radiation with light from an artificial light source to compensate for periods of insufficient levels of solar light to maintain a desired illumination level within an interior space comprising an artificial light source connected to an electrical power source with switch means for selectively energizing said light source, actuator means for controlling the on-off operation of the switch means, a light sensor connected to the actuator means for controlling the actuator means in response to the illumination level of the interior space, and a limit switch carried adjacent the actuator for limiting the movement of the actuator within a predetermined range so as to prevent further movement thereof during detection of erroneous illumination conditions.

Abstract: Improved solar sensor and tracker apparatus is described in which an extremely low cost high angular accuracy sensor and tracking device utilizing a symmetrical sensor shade and sensor arrangement is described. An improved circuit control for electric motor drive of the tracker apparatus is also described in which a relatively high speed track operation followed by a relatively slow speed homing in motion is automatically provided by the control circuit driving the electric motors.

Abstract: An ambient light responsive switch for street lamps or other loads, includes a thermostatic switch of the thermal time delay relay type, connecting a load to a current source and exposed to a heater resistor and snap opening and closing at relatively high and low temperature values. An ambient light exposed photoconductor, a first resistor and the heater resistor are series connected across the current source, and the first resistor and a second resistor are series connected across the switch. With the closing of the switch in response to a low light value the load is energized and the resistance in series with the heater resistor is accordingly lowered to increase the heater current. With the opening of the switch in response to a high light value the load is deenergized and the resistance in series with the heater resistor is accordingly increased to decrease the heater current and reduce the sensitivity of the switch.

Abstract: A circuit for controlling the energization of a night lighting load or the like, in which failure of the main circuit to control and shut off electrical supply to the load during daylight hours leads to permanent shutdown of the electrical supply to the load. Two photosensitive elements are provided in the circuit. One element, e.g. a photocell, is a main control which periodically operates a relay and supplies electricity to the load, i.e. at night. The second element, e.g. a second photocell, is connected in the circuit, together with a second relay, in such a manner that failure of the first relay to operate and open the load circuit during daylight hours will cause the second relay to operate and permanently open the load circuit.

Abstract: A light-sensitive lamp adaptor is small enough to fit in most indoor or outdoor lamps between the lamp socket and the light bulb. The adapter contains a solid state electronic circuit including a photocell which is in good thermal contact with the thermally conductive base of the adapter so that these electrical components are not heated excessively. A small window in the side of the adapter is movable about the axis of the adapter so that the photocell will respond only to light incident on the window from a given direction and the size of the window can be adjusted so that the unit will respond only to light of a given intensity.

Abstract: A light-responsive electric switch is composed on the one hand by an electronic circuit constituted, in the case of direct-current supply, by a voltage divider comprising a fixed resistor and a variable resistor forming the photo-conductive cell, by four transistors which are blocked or rendered conductive according to the illumination of the photo-conductive cell, by a change-over switch transmitting the voltage to another transistor into the collector circuit of which a motor is connected, and on the other hand by an electro-mechanical device constituted by a bistable trigger circuit controlling the motor, by a step-down gearing meshing with a pinion fixed on the shaft of this motor, by cams fast with the shaft of the final pinion of the step-down gearing and by one or more contacts which close or interrupt one or more lighting circuits.