Passive infrared sensor: Difference between revisions
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A '''Pyroelectric InfraRed sensor''' '''(PIR sensor)''' is an [[electronic device]] that measures [[infrared]] (IR) light radiating from objects in its field of view. Because it does not emit any energy, it is often mistakenly called a Passive Infrared Sensor. PIR sensors are often used in the construction of ''PIR-based [[motion detector]]s'' (see below). Apparent motion is detected when an infrared source with one [[temperature]], such as a [[human]], passes in front of an infrared source with another temperature, such as a [[wall]].<ref>[http://www.gadgetshack.com/motionsensor.html "PIR |
A '''Pyroelectric InfraRed sensor''' '''(PIR sensor)''' is an [[electronic device]] that measures [[infrared]] (IR) light radiating from objects in its field of view. Because it does not emit any energy, it is often mistakenly called a Passive Infrared Sensor. PIR sensors are often used in the construction of ''PIR-based [[motion detector]]s'' (see below). Apparent motion is detected when an infrared source with one [[temperature]], such as a [[human]], passes in front of an infrared source with another temperature, such as a [[wall]].<ref>[http://www.gadgetshack.com/motionsensor.html "PIR Moti |
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All objects emit what is known as [[black body radiation]]. It is usually infrared radiation that is invisible to the human [[eye]] but can be detected by [[electronic device]]s designed for such a purpose. The term ''passive'' in this instance means that the PIR device does not emit an infrared beam but merely passively accepts incoming infrared radiation. |
All objects emit what is known as [[black body radiation]]. It is usually infrared radiation that is invisible to the human [[eye]] but can be detected by [[electronic device]]s designed for such a purpose. The term ''passive'' in this instance means that the PIR device does not emit an infrared beam but merely passively accepts incoming infrared radiation. |
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Revision as of 20:20, 1 August 2009
A Pyroelectric InfraRed sensor (PIR sensor) is an electronic device that measures infrared (IR) light radiating from objects in its field of view. Because it does not emit any energy, it is often mistakenly called a Passive Infrared Sensor. PIR sensors are often used in the construction of PIR-based motion detectors (see below). Apparent motion is detected when an infrared source with one temperature, such as a human, passes in front of an infrared source with another temperature, such as a wall.Cite error: A <ref> tag is missing the closing </ref> (see the help page). In such a circuit, a non-differential PIR output is used. The output signal is evaluated according to a calibration for the IR spectrum of a specific type of matter to be observed. By this means, relatively accurate and precise temperature measurements may be obtained remotely. Without calibration to the type of material being observed, a PIR thermometer device is able to measure changes in IR emission which correspond directly to temperature changes, but the actual temperature values cannot be calculated.
See also
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