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A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors . PIR sensors are commonly used in security alarms and automatic lighting applications.
The sensitivity of a loudspeaker is usually expressed as dB / 2.83 V RMS at 1 metre. [citation needed] This is not the same as the electrical efficiency; see Efficiency vs sensitivity. This is an example where sensitivity is defined as the ratio of the sensor's response to the quantity measured.
A camera trap with a passive infrared (PIR) sensor. A camera trap is a camera that is automatically triggered by motion in its vicinity, like the presence of an animal or a human being. It is typically equipped with a motion sensor—usually a passive infrared (PIR) sensor or an active infrared (AIR) sensor using an infrared light beam. [1]
A passive infrared detector mounted on circuit board (right), along with photoresistive detector for visible light (left). This is the type most commonly encountered in household motion sensing devices and is designed to turn on a light only when motion is detected and when the surrounding environment is sufficiently dark.
Occupancy sensor types include: PIR sensors, which work on heat difference detection, measuring infrared radiation.Inside the device is a pyroelectric sensor which can detect the sudden presence of objects (such as humans) who radiate a temperature different from the temperature of the background, such as the room temperature of a wall.
A sensor's sensitivity indicates how much its output changes when the input quantity it measures changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, its sensitivity is 1 cm/°C (it is basically the slope dy/dx assuming a linear characteristic). Some sensors can also affect what they measure ...
Infrared signature, as used by defense scientists and the military, is the appearance of objects to infrared sensors. [1] An infrared signature depends on many factors, including the shape and size of the object, [2] temperature, [3] and emissivity, reflection of external sources (earthshine, sunshine, skyshine) from the object's surface, [4] the background against which it is viewed [5] and ...
A nondispersive infrared sensor (or NDIR sensor) is a simple spectroscopic sensor often used as a gas detector.It is non-dispersive in the fact that no dispersive element (e.g a prism or diffraction grating as is often present in other spectrometers) is used to separate out (like a monochromator) the broadband light into a narrow spectrum suitable for gas sensing.