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  2. Passive infrared sensor - Wikipedia

    en.wikipedia.org/wiki/Passive_infrared_sensor

    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.

  3. Motion detector - Wikipedia

    en.wikipedia.org/wiki/Motion_detector

    A motion detector attached to an outdoor, automatic light. A motion detector is an electrical device that utilizes a sensor to detect nearby motion (motion detection).Such a device is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area.

  4. Pyroelectricity - Wikipedia

    en.wikipedia.org/wiki/Pyroelectricity

    Internals of a pyroelectric sensor. Pyroelectricity (from Greek: pyr (πυρ), "fire" and electricity) is a property of certain crystals which are naturally electrically polarized and as a result contain large electric fields. [1]

  5. Occupancy sensor - Wikipedia

    en.wikipedia.org/wiki/Occupancy_sensor

    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.

  6. Security alarm - Wikipedia

    en.wikipedia.org/wiki/Security_alarm

    The passive infrared (PIR) motion detector is one of the most common sensors found in household and small business environments. This sensor does not generate or radiate energy; it works entirely by detecting the heat energy given off by other objects. PIR sensors identify abrupt changes in temperature at a given point.

  7. Infrared detector - Wikipedia

    en.wikipedia.org/wiki/Infrared_detector

    An infrared detector is a detector that reacts to infrared (IR) radiation. The two main types of detectors are thermal and photonic ( photodetectors ). The thermal effects of the incident IR radiation can be followed through many temperature dependent phenomena. [ 2 ]

  8. Prisoners of Profit - The Huffington Post

    projects.huffingtonpost.com/prisoners-of-profit?...

    In 2001, an 18-year-old committed to a Texas boot camp operated by one of Slattery’s previous companies, Correctional Services Corp., came down with pneumonia and pleaded to see a doctor as he struggled to breathe.

  9. Nondispersive infrared sensor - Wikipedia

    en.wikipedia.org/wiki/Nondispersive_infrared_sensor

    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.