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In typical Sun sensors, a thin slit at the top of a rectangular chamber allows a line of light to fall on an array of photodetector cells at the bottom of the chamber. A voltage is induced in these cells, which is registered electronically. By orienting two sensors perpendicular to each other, the direction of the Sun can be fully determined. [2]
All daylight harvesting systems use a light level sensor, a photosensor, to detect the prevailing light level, luminance or brightness, in open-loop or closed-loop systems. Photosensors are used to adjust electric lighting based on the available daylight in the space.
An optical sensor is generally part of a larger system that integrates a source of light, a measuring device, and the optical sensor. This is often connected to an electrical trigger. The trigger reacts to a change in the signal within the light sensor. An optical sensor can measure the changes from one or several light beams.
The detecting range of a photoelectric sensor is its "field of view", or the maximum distance from which the sensor can retrieve information, minus the minimum distance. A minimum detectable object is the smallest object the sensor can detect. More accurate sensors can often have minimum detectable objects of minuscule size.
Typically, bulbs of 21 to 27 watts producing 280 to 570 lumens (22 to 45 mean spherical candlepower) are used for stop, turn, reversing and rear fog lights, while bulbs of 4 to 10 W, producing 40 to 130 lm (3 to 10 mscp) are used for tail lights, parking lights, side marker lights and side turn signal repeaters.
The source of all daylight is the Sun. The proportion of direct to diffuse light impacts the amount and quality of daylight. [1] "Direct sunlight" reaches a site without being scattered within Earth's atmosphere. Sunlight that is scattered in the atmosphere is "diffused daylight". Sunlight reflected off walls and the ground also contributes to ...
In 1994, the Windows and Daylighting Group at Lawrence Berkeley National Laboratory (LBNL) developed a series of horizontal light pipe prototypes to increase daylight illuminance at distances of 4.6-9.1 m, to improve the uniformity of daylight distribution and luminance gradient across the room under variable sun and sky conditions throughout ...
This linear 'sensor' is typically a few metres up to a few hundred metres in length. Open-path detectors can be contrasted with infrared point sensors . They are widely used in the petroleum and petrochemical industries, mostly to achieve very rapid gas leak detection for flammable gases at concentrations comparable to the lower flammable limit ...