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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.
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.
Conceptual through-beam system to detect unauthorized access to a secure door. If the beam is interrupted, the detector triggers an alarm. A photoelectric sensor is a device used to determine the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in ...
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.
A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintillator and re-emit it in the form of electrons via the photoelectric effect. The subsequent ...
The most common sensor applications with a sampling rate of less than 1000 Hz are CCD or CMOS cameras. The sensor is partitioned into individual pixels whose exposure value can be read out sequentially. The position of the light spot can be computed with the methods of photogrammetry directly from the brightness distribution.
Indirect detectors contain a layer of scintillator material, typically either gadolinium oxysulfide or cesium iodide, which converts the x-rays into light.Directly behind the scintillator layer is an amorphous silicon detector array manufactured using a process very similar to that used to make LCD televisions and computer monitors.
Smoke detector mounted on a ceiling. A smoke detector is a device that senses smoke, typically as an indicator of fire.Smoke detectors/alarms are usually housed in plastic enclosures, typically shaped like a disk about 125 millimetres (5 in) in diameter and 25 millimetres (1 in) thick, but shape and size vary.