Abstract: An arrangement for detecting an electromagnetic energy such as ambient light is provided with a photodetector having an input for receiving electromagnetic energy, and an output for producing an electrical characteristic responsive to the electromagnetic energy. A hollow conduit having a first end is arranged to receive a portion of the ambient electromagnetic energy, and a second end thereof is arranged in the vicinity of the photodector input. Thus, a portion of the received potion of the ambient electromagnetic energy impinges upon the photodetector input. The first end of the hollow conduit is terminated at a predetermined angle with respect to an axis of the first end, and a diffuser is optionally disposed in the vicinity of the first end of the hollow conduit.

Abstract: A system for detecting the presence of rain droplets on a windshield employs a source of radiant energy, such as an LED, and a photodetector installed on the instrument panel of a vehicle. The LED and the photodiode are arranged with respect to one another such that light from the LED cannot reflect directly off the windshield onto the photodiode. Only when the light from the LED is back scattered by an environmental condition, such as the raindrops on the exterior of the windshield, the condensation of moisture on the interior of the windshield, or the presence of smoke in the cabin, will the photodiode receive the light from the LED. Each of these environmental conditions has a predeterminable characteristic signature that permits the processing of data to detect same.

Abstract: An apparatus and method for controlling the operation of the windshield wipers of a vehicle in response to the deposition of water on the exterior of the windshield; the operation of the air conditioning system in response to the formation of water condensation on the interior of the windshield of the vehicle; and the operation of the ventilation system in response to the presence of smoke in the cabin of the vehicle.

Abstract: A system for detecting the presence of rain droplets on a windshield employs a source of light, such as an LED, and a photodetector installed on the instrument panel of a vehicle. The LED and the photodiode are arranged with respect to one another such that light from the LED cannot reflect directly off the windshield into the photodiode. Only when the light from the LED is backscattered by an environmental condition, such as the raindrops on the exterior of the windshield, the condensation of moisture on the interior of the windshield, or the presence of smoke in the cabin, will the photodiode receive the light from the LED. Each of these environmental conditions has a predeterminable characteristic signature which permits the processing of data to detect same.

Abstract: A combined ambient light magnitude and light source direction sensor controls the headlamps and cabin climate of a vehicle. The combined unit employs a photodiode having a predetermined spectral response and a diffuser which also has a predetermined spectral response, the spectral responses being combined to achieve an overall spectral response which corresponds to that of the human eye. With this arrangement, the headlamps of a motor vehicle are turned on and off under different ambient light conditions, in a manner which corresponds to the perception of the driver. In addition, a light modulator provides the combined unit with a sensitivity to the angular location of the sun with respect to the vehicle in which the unit is installed. Such angular sensitivity facilitates in determining the portion of the interior of the vehicle undergoing thermal loading by the sun, and facilitates a corresponding adjustment of the climate control system.

Abstract: A photosensor arrangement produces an electrical signal responsive to the position of a source of light by employing a mask situated at a predetermined height above a plurality of photodetectors, such that as the sun moves with respect to the apparatus, a shadow is cast which is responsive to the location of the sun. An apparatus constructed in accordance with the invention has a plurality of photosensors, each having a respective substantially planar light-sensitive surface for receiving the input light from the sun over a predetermined range of positions. In a preferred embodiment where compactness is desired, the planar light-sensitive surfaces are arranged in a substantially coplanar relationship with respect to one another. The light mask, which has opaque and transparent portions, is arranged to overlie the substantially planar light-sensitive surfaces for determining the position-responsive sensitivity characteristic of the apparatus.

Abstract: A twilight sensor for controlling the headlamps of vehicles employs a photodiode having a predetermined spectral response and a diffuser which also has a predetermined spectral response, the spectral responses being combined to achieve an overall spectral response which corresponds to that of the human eye. With this arrangement, the headlamps of a motor vehicle are turned on and off under different ambient light conditions, in a manner which corresponds to the perception of the driver. In addition, the invention employs a control system which turns the lights on rapidly after the vehicle enters a tunnel.

Abstract: A photodetector system for producing electrical signals responsive to the orientation of a light source, such as the sun, with respect thereto utilizes a diffuser to eliminate position-dependent sensitivities of the photocathode. The extent to which the diffuser or the photocathode itself is exposed to the incident radiation can be controlled by a shroud or by applying an absorptive coating in a predetermined pattern on an absorber cap, or on the diffuser directly. The shroud, by its configuration and its height above the photodetector, defines the range of angles of elevation and azimuth at which the diffuser can be illuminated. Such angles can also be controlled with printed or sprayed-on markings on the diffuser or absorber cover which form an opaque coating so as to prevent light transmission over predetermined regions. A fine dot pattern may be applied to the diffuser or the absorber cover, so that only partial transmission of the light can be achieved therethrough.

Abstract: A diode thermometer wherein a current source is operated to cause a temperature sensing diode to be subjected to operation at a first current level and then a second current level different from the first current level. A voltage generated from the diode by the switching of the current is applied to a circuit which up integrates the voltage for a certain time interval at the conclusion of which a known reference voltage is applied to the integrator, of opposite sense to the previous signal so that the integrator now integrates in the opposite direction. A capability is provided such that the integrator starts from a zero reference level when it begins to integrate, and when it is integrating the known reference signal it returns toward this zero reference. A comparator detects return of the integrator output signal to the zero reference.