Abstract:
A volumetric occupancy counting system that may be applied to a security system of a building management system includes a focal plane array (62) and a Fresnel lens (75). The focal plane array has a plurality of radiant energy sensors (82) configured to convert radiant energy into an electrical signal. The Fresnel lens has a plurality of lenslets (02) each including a focal length configured to map one occupant into a pre-determined number of radiant energy sensors of the plurality of radiant energy sensors.
Abstract:
An infra-red motion detector lens (50) is disclosed. The lens is configured to focus radiation on a 2 x 2 quad detector (10) that has a plurality of detector regions (11-14) capable of providing a first signal or a second signal. The lens comprises a series of lenslets, each of which can image respective regions (60, 70). The fields of view of the lenslets are partially overlapping in such a way that a source of radiation in a particular location can simultaneously project radiation onto two detector regions (11-14) through more than one respective lenslet. The detector regions (11-14) are diagonally opposite one another and are arranged to provide the same type of signal. A grid of overlapping lenslets can be constructed in this way so that two lenslets can increase the signal strength created at the detector by focusing radiation onto the same detector to create the same type of signal.
Abstract:
A self-powered energy harvesting unit/controller receives motion data from one or more self-powered sensors via low power wire. The energy harvesting unit sends signals wirelessly to a system to perform certain functions as a result of received motion signals or the absence of such motion signals.
Abstract:
A detector, system including a detector and method for sensing motion within a detection region. The detector has a detection element and a focusing element aiming received energy corresponding to a presence within the detection region toward the detection element. The focusing element has a plurality of sections in which each of the plurality of sections establishes a corresponding detection zone within the detection region. The plurality of sections are arranged to allow a motion vector to be determined for an object passing through the detection region. The system includes a detector that generates pulses each time presence in a detector zone is detected as well as a central alarm panel. The central alarm panel receives the pulses and has processor that evaluates the timing between electrical pulses to determine the motion vector.
Abstract:
A passive infrared sensor uses a modified lens or mirror to vertically elongate the detection zones in regions close to the sensor. This vertical elongation reduces the signal produced by a small pet, such as a cat, while the greater height of a human intruder produces a larger signal. The sensor advantageously uses a single detector and the same algorithm is used to distinguish human intruders from small pets.
Abstract:
A focussing element (50) is incorporated in an infrared detector, the focussing element (50) being in the form of a series of grooves (54) which form one or more diffractive optical elements. The diffractive optical elements may have spatial filtering properties and may also be arranged to correct chromatic aberrations. Alternatively, the focussing element may comprise a holographic optical element.
Abstract:
Provided is a lighting device including a light source for emitting light, a sensor configured to detect infrared radiation from a plurality of locations along a path in the field of view of the sensor, at least one attenuation element arranged between at least one location of the plurality of locations and the sensor so as to attenuate or block infrared radiation emitted from the at least one location before it reaches the sensor, and a controller. The at least one attenuation element is further arranged in relation to the field of view of the sensor for the signal output from the sensor to indicate, when an occupant is moving along the path, a direction of movement of the occupant along the path. The controller is arranged to control the light source based on the direction of movement of the occupant, and a cover plate is arranged between the at least one location of said plurality of locations and the sensor, and also arranged between the at least one location and the light source, wherein the cover plate is transparent or translucent to said visible light, wherein the at least one attenuation element forms part of the cover plate, and wherein outside, or away from, the attenuation element, the cover plate is at least partly transparent to infrared radiation.
Abstract:
Occupancy detection is an increasingly important part of building control logic, as new systems and control logic greatly benefit from human-in-the-loop sensing. Current approaches such as CO 2 monitoring, acoustic detection, and PIR based motion detection are limited in scope, as these variables are a proxy for occupancy, and at best can be roughly correlated to occupancy, and cannot reliably provide a count of the number of occupants. The disclosed sensor uses thermal information that is continually being emitted by human occupants and optical processing to count and spatially resolve the location of occupants in a room, allowing ventilation flow rates to be properly controlled and directed, if enabled. Occupant detection and counting cheaply and reliably without moving parts is the holy grail of building controls at the moment, which are the basic design principles behind the disclosed inexpensive, static, and stable thermographic occupancy detection sensor.
Abstract:
A detector unit for a lighting control system comprises a sensor and a reflector (1) arranged to reflect signals from a detection footprint (9) into the sensor. The reflector (1) comprises a multiplicity of reflective elements (5) arranged in a ring (15) coaxial with the sensor. At least some of the reflective elements (5) may be at differing angles of tilt, such that the detection footprint (9) is non-circular. The detector unit may be arranged such that the tilt of the reflective elements (5) is adjustable such that the shape of the detection footprint (9) may be adjusted.