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Photoelectric Sensors
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About Light Sensors
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What was a light sensor?
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How does a light sensor work?
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Overview of light sensors
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Tips for buying a light sensor
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Where are light sensors used?
What was a light sensor?
A light sensor measures the brightness through a special brightness sensor. This can mean the measurement of daylight as well as the measurement of artificial light indoors.
If the incidence of light or the light intensity changes, the sensor triggers the function assigned to it. As an alternative to the time switch, for example, it provides for the lighting of the house number. This is done at a pre-determined illuminance.
How does a light sensor work?
The light sensor uses the lux measurement unit to measure the brightness of its surroundings. If a previously defined value is undershot, the function assigned to the sensor is triggered.
Alternatively, there are light sensors whose function comes into force by interrupting a mostly invisible light beam. As a rule, these sensors serve as a practical door opener. However, the beam can also act as a safety mechanism, for example by triggering an alarm signal when the beam is broken.
Overview of light sensors
Conrad has components and finished products for different applications.
CMOS Sensors & MiniCam Modules
These are image sensors used in digital cameras. They turn light into tension by
differentiating light and dark from each other. A distinction between individual colors is usually not made, but is possible with special filters.
Photo Sensors
A photodetector is the component of light barriers that is responsible for converting the light beam into an electrical signal. Depending on the model, the detector is available within a device or as a separate element.
Twilight sensors & twilight switches
This is a brightness sensor that measures when the twilight or night starts outside. Also here, the measurement takes place in Lux. Twilight sensors are installed in addition to the outdoor lighting. A photodiode is integrated, which measures the brightness.
The previously set value indicates when the device is switched on or off. These devices are practical, for example, when house number or name lighting at the property is not to be regulated by a timer. Once set, the device depends on the set value. The illuminance can also be determined depending on the device.
Light Barriers & Buttons
A light beam is generated by the light sensor by being transmitted from a
transmitter to a receiver; usually not as visible light for the human eye. Transmitter and receiver devices can already be included in the same product.
The light barriers transform the light beam into an electrical signal that triggers a reaction if the beam is interrupted. This technology is used, for example, under automatic soap dispensers.
Tips for buying a light sensor
Always select the exact light sensor that is suitable for the desired application area. If you want to create a light barrier, you need a light sensor accordingly. If you want to trigger a function when the brightness reaches a certain value, a twilight sensor is the right choice.
In addition, it is important to take into account the space requirements of the sensors. For this purpose, measure the area of application – such as a door – precisely and align it with the dimensions of the sensor. If you want to use the sensor outdoors or under more extreme conditions, the minimum and maximum operating temperature also play a role. For example, some twilight switches do not work at more than 35 degrees – which was quite possible in case of direct sunlight in the high summer.
Good to know: Saving energy
If you want to save energy with your twilight sensor, for example, you should pay attention to the use of an LED lamp. Due to the brightness-dependant radiation of house number and co you save electricity anyway, the LED-lamp further reduces the power costs.
Where are light sensors used?
For example, active components in cameras provide the so-called photoelectric effect, and sensors are also used in many robots. Light sensors can detect, for example, household robots, where they hit obstacles and drive around them in a targeted manner.
However, light sensors are also popular in vehicles. They enable the automatic switching of the low-beam light on or off by interrupting or reaching a certain level of brightness. This allows sensors in BMW, Mercedes and Co. to ensure safe tunnel passage with automatically switched-on light.