EP3379507B1 - Device and method for determining the direction in passageways - Google Patents

Description

The invention relates to a device for direction detection in passages with a housing, a first PIR sensor and a second PIR in the housing and each with a viewing window transparent to infrared radiation in the detection area in front of a PIR sensor. There is a detection zone between a PIR sensor and its viewing window to reduce the detection area.

Out of DE 10 2006 019 941 A1 a device for detecting people, animals or objects is known. The device includes at least one PIR sensor and an optical assembly that directs incident infrared radiation onto the PIR sensor. The received signal from the PIR sensors is forwarded to an evaluation unit, where it is amplified, evaluated and the result is made available at an output. There is at least one thermal source in the vicinity of the PIR sensor that is used to check the PIR sensor. An active intensity button checks whether the PIR sensor's viewing area is clear.

In DE 40 01 219 C1 A monitoring device for a passenger corridor is described, in which a PIR sensor is arranged on the ceiling between two light buttons in the direction of passage. The time-offset signals from the light buttons can be used to determine the direction of passage of a person. The signal from the PIR sensor indicates whether it is one or more people.

US 4,799,243 A discloses a device for direction-dependent counting of people in passages. The infrared rays for two PIR sensors are restricted using a mask element positioned in the beam path behind a filter element and a lens. Through this in the beam path of the two PIR sensors The beam path is divided into two monitoring zones by the common mask element lying on the two PIR sensors.

US 4,943,800 A describes an intrusion detection system with three pyroelectric detectors arranged next to each other. In a housing there are two openings behind a lens, separated from each other by a web. There is a common IR filter between the openings and the PIR sensors.

DE 196 39 318 C1 describes a multiple passive infrared motion detector (PIR) with a specially designed optical and isolation system. Two independent PIR motion detectors are united close to each other in a common housing. Fresnel optics are designed in such a way that every point in the monitoring area is detected separately by each detector with the same segment type. Furthermore, special movable partition slats are arranged around the PIR motion detector in degree steps in order to open part of the segments of one PIR detector by moving the partition slats and at the same time close the segments of the same type of the other PIR detectors.

WO 01/67414 A1 discloses a passive infrared sensor with a special lens or mirror for vertically extending the detection area close to the sensor. The optical extension means that people generate a stronger signal on the sensor than smaller pets such as cats. In this way, a suitable evaluation algorithm can be used to distinguish whether people or animals pass through the sensor.

The GB 2 507 818 A as well as the GB 2 332 955 A also deal with the distinction between humans and animals in connection with infrared detectors in intruder alarm systems. The GB 2 507 818 A uses section-by-section masking of infrared sensors to attenuate infrared signals without completely masking out a specific detection area. The GB 2 332 955 A uses a special lens system consisting of a variety of convex and cylindrical lenses, with the cylindrical lenses having a vertically lower detection range are aligned and have selective attenuation in order to be able to block out infrared signals from animals.

Based on this, it is the object of the present invention to create an improved device in which the direction detection in passages is improved with a compact design.

The task is solved with a device having the features of claim 1. Advantageous embodiments are described in the subclaims.

It is proposed that the detection zone with contours of the housing is designed as a slot-shaped tunnel, which extends adjacent to the viewing window towards the respective PIR sensor and limits IR radiation incident through the viewing window in such a way that the IR radiation in a 90 ° angle with a tolerance deviation of up to +/- 20° hits the sensitive surface of the PIR sensor. This enables a structurally determined detection zone that can be produced cost-effectively using simple means. Such contours ensure that predominantly IR radiation hits the PIR sensor at an angle of 90 degrees to the sensor surface. This reduces the risk of unwanted detection by the PIR sensors. Furthermore, the detection zone is optimized by a structural boundary in such a way that the detection area is advantageously limited. The detection zone serves to limit the detection area of the sensor and is determined by the distance between the PIR sensor and its viewing window. The detection area is the area outside the device in which IR radiation can be detected by the PIR sensors. Each PIR sensor has a detection area that is limited by the respective detection zone.

A PIR sensor in the sense of the present invention is understood to mean any type of sensor that detects infrared radiation, ie thermal radiation. Such PIR sensors are designed, for example, for passive infrared detection via the pyroelectric effect or via the thermoelectric effect, which is also known as the reverse Seebeck effect (thermopile/thermopile) or reverse Peltier effect.

The detection zone reduces the detection range of the PIR sensor in such a way that infrared radiation (IR radiation), which is emitted by living beings in the form of thermal radiation, is blocked out outside an ideal axis of 90 degrees (at an angle of 360 degrees) to the sensor surface becomes.

The specifically limited detection range of the PIR sensors for detecting IR radiation makes it possible to detect IR radiation with a time delay using at least two PIR sensors and with a compact design. If IR radiation hits the sensitive surface of a PIR sensor, it heats up and creates an electrical voltage. The time-delayed voltage signals from the PIR sensors can be used to determine the direction of passage of people in passageways, such as doorways, staircases or corridors. The detection zone ensures a distance between the PIR sensor and the associated viewing window. An increased distance promotes masking out of the IR radiation outside the ideal axis of 90 degrees to the sensor surface.

It would also be conceivable that the device could provide additional information, such as the number of people who have passed through a passage, depending on the sensor signals detected by the PIR sensors.

The suppression of IR radiation outside the ideal axis of 90 degrees to the sensor surface enables a compact arrangement of the first PIR sensor and the second PIR sensor to one another, so that the detection areas of the PIR sensors do not overlap or only partially overlap and thus a time-delayed detection of the Enable IR radiation. In this way, such a device can be easily installed in narrow passages, such as a door. The device can be assembled using a fastener, such as adhesive. However, installation via a screw connection or similar would also be conceivable.

Viewing windows that are transparent to infrared waves can have attenuation due to structural reasons. The arrangement of the PIR sensors and the size (particularly length and width) of the detection zone should then be coordinated in such a way that that the minimum sensitivity of the sensitive surface of the PIR sensors is exceeded when IR radiation hits.

In a preferred embodiment, the first PIR sensor is separated from the second PIR sensor in the horizontal direction, i.e. H. in the direction of passage in the installation position specified for passage detection. The direction of passage of people in passages can be determined using a simple design, since the PIR sensors detect the IR radiation one after the other depending on the direction of passage, since the respective detection areas are determined by the spacing of the PIR sensors and the limitation of the detection areas by the respective ones Detection zones do not overlap or only partially overlap.

It is also possible to arrange the PIR sensors in which they are spaced apart in a vertical direction. The time-delayed detection of the IR radiation can then be achieved by rotating the PIR sensors around their vertical axis, so that the detection areas of the PIR sensors do not overlap or only partially overlap, but are still within the passage.

It is particularly advantageous if the detection range of the first PIR sensor and/or the second PIR sensor is limited by the detection zones in such a way that the detection range is restricted in the horizontal direction in the installation position specified for passage detection. Due to the restriction in the horizontal direction, the PIR sensors can be arranged in close proximity to one another, so that the detection zones of the PIR sensors only partially overlap or not at all. In this way, the probability of an unwanted detection of a PIR sensor at an incorrect time can be reduced, for example if the second PIR sensor triggers before the first PIR sensor in the direction of passage.

Restricting the horizontal detection range further minimizes the disruptive influence of IR radiation caused by people outside the passageway. This means that people are only detected within the passage and are not detected before the passage. The detection area is ideal horizontally limited by the detection zone in such a way that it does not extend beyond the frame of the passage.

It is further advantageous if the detection range of the first and/or the second PIR sensor is limited by the detection zone in such a way that the detection range is expanded upwards in the vertical direction in the installation position intended for passage detection. This means that incident IR radiation can be sufficiently detected above the PIR sensor. This ensures that IR radiation, which is predominantly emitted by exposed body parts such as the head area, neck, hands and arms, is also detected by the PIR sensors. Detecting IR radiation from this area increases the probability of detection and thus reduces the risk of not detecting people, since the emission of IR radiation is usually limited by clothing and the like.

It is further advantageous if the detection range of the first and/or the second PIR sensor is limited by the detection zone in such a way that the detection range is restricted downwards in the vertical direction. In this way, the IR radiation emitted by smaller creatures is not detected by the PIR sensors. Limiting the detection range downwards allows smaller creatures to be hidden, such as pets. The user is given a certain degree of freedom in the installation height of the device. This means that the device can be easily set up individually depending on the application.

According to an advantageous development, the housing has thermal insulation. PIR sensors work with the ambient temperature as a reference when recording the object temperature or the emitted IR radiation. Thermal insulation makes it possible to reduce or completely eliminate external thermal influences, such as air movements in living spaces (drafts, ventilation processes, fans, people walking past).

The slot-shaped tunnel of the housing has an IR-absorbing material to limit the detection area. This can be done, for example, via a black one surface can be realized. The IR-absorbing surface of the slot-shaped tunnel enables a reduction in the reflection of laterally incident IR rays within the housing and thus a detection of IR radiation outside the ideal axis of 90 degrees to the sensor surface. This reduces the likelihood of unwanted detection outside the respective passage.

It is advantageous if the device has a wireless communication unit, in particular a uni- or bi-directional radio communication unit. This enables wireless communication of the sensor signals from the PIR sensors or the transit data derived from them by the device to an independent device, for example a host. The signals can be evaluated in a simple manner and make it possible to view data live. Complex cabling of the device to a central unit is then not necessary.

It is advantageous if the detected signal from the PIR sensors is forwarded by means of a wireless connection, in particular a radio connection, to an independent device, for example a host, for further processing. In this way, the effort for a network-operated application can be minimized.

The device can also have more than two PIR sensors. In this respect, the indefinite term “a” should be understood in the sense of “at least one” and not as a number word.

Figur 1

- eine Ausführungsform einer Vorrichtung zur Richtungserkennung in einer Explosionsansicht;

Figur 2

- ein Ausschnitt der Vorrichtung mit einem PIR-Sensor als Prinzipzeichnung in Seitenansicht;

Figur 3

- eine Prinzipzeichnung eines Erfassungsbereiches eines Ausschnittes der Vorrichtung gemäß der Figur 2 für einen PIR-Sensor;

Figur 4

- ein Anwendungsbeispiel einer Ausführungsform der Vorrichtung gemäß Figur 1 in einem Durchgang.

The invention is explained in more detail below by way of example with the accompanying drawings. Show it:

Figure 1

- an embodiment of a device for direction detection in an exploded view;

Figure 2

- a detail of the device with a PIR sensor as a schematic drawing in a side view;

Figure 3

- a schematic drawing of a detection area of a section of the device according to Figure 2 for a PIR sensor;

Figure 4

- an application example of an embodiment of the device according to Figure 1 in one pass.

In the figures, the same reference numerals are used for corresponding elements.

The ones in the Figure 1 Device 1 shown has a housing 2 which contains a first PIR sensor 3 and a second PIR sensor 4. Both the first PIR sensor 3 and the second PIR sensor 4 are each assigned a viewing window 5 that is transparent to infrared radiation and is spaced apart from the respective PIR sensor 3, 4. The housing 2 has a slot-shaped tunnel 6 between the PIR sensor 3, 4 and the associated viewing window 5. If IR radiation (heat radiation) emitted by living creatures hits one of the PIR sensors 3, 4, then the surface of the PIR heats up -Sensors 3, 4 and thereby causes a voltage. Due to the spacing of the PIR sensors 3, 4 in the horizontal direction, seen in the installed position for passage detection, the PIR sensors detect emitted IR radiation one after the other. The time-offset voltages can be used to determine the direction of passage of a person or living being, depending on which of the PIR sensors 3, 4 detects the IR radiation first.

The Figure 2 shows a section of the device 1 with a PIR sensor 3, 4 in a schematic drawing in a side view. The detection zone 7 is formed by a slot-shaped tunnel 6 formed integrally with the housing 2. The slot-shaped tunnel 6 causes IR radiation outside an ideal axis 90 degrees to the respective PIR sensor surface is largely hidden. IR radiation incident through the viewing window 5 is limited by the slot-shaped tunnel 6 in such a way that the IR radiation hits the sensitive surface 9 of the PIR sensor 3, 4 essentially at a 90° angle. “Substantially” is understood to mean a tolerance deviation of +/- 10° up to +/- 20°. The PIR sensor 3, 4 is arranged on a circuit board 10 for further processing of the signal. This limits the viewing angle (detection angle) of the detection area 8.

Figure 3 shows a device that is comparable to Figure 2 is constructed. It can be seen that the maximum detection area 8 outside the device 1 is limited by the structural arrangement of the slot-shaped tunnel 6 and the PIR sensor 3, 4 in a detection zone 7. The slot-shaped tunnel 6 can optionally be designed such that the detection area 8 is restricted in the horizontal direction (not visible in this view) and expanded upwards in the vertical direction and restricted downwards. In this way it is ensured that people are not detected outside the passage by a PIR sensor 3, 4, but within the passage the probability of detection, in particular of IR radiation emitted by the head area of a person, is increased. The vertical downward restriction reduces unwanted detection of small creatures such as pets.

The detection area 8 can be defined by setting a lateral offset of the PIR sensor 3, 4 to the slot-shaped tunnel 6.

Figure 4 shows an application example of an embodiment of the device 1 according to Figure 1 . The device 1 is mounted within a passage at a certain height, which can be individually adapted to the needs of the user. The detection area 8 for detecting people is extended upwards in the vertical direction so that as much IR radiation as possible can be detected by the PIR sensors 3, 4, and restricted downwards in order to exclude the detection of small living beings such as pets. The detection range in the horizontal direction is limited in such a way that the detection areas 8 of the first PIR sensor 3 and the second PIR sensor 4 do not or only partially overlap and, if possible, not extend beyond the frame of the passage. If a living being passes through the passage and thereby the detection area 8 of the PIR sensors 3, 4, the PIR sensors 3, 4 will successively record the emitting IR radiation of the living being, with the direction of passage of the living being being deduced based on the time offset of the detection can. In addition, a pass count can be made from the number of transit events. The device can also be used as a sensor in an alarm system to detect unauthorized entry into a section of building or area behind the passage.

Claims (8)

1. Device (1) for direction recognition in passages with a housing (2), a first PIR sensor (3) and a second PIR sensor (4) in the housing (2) and with a viewing window (5) in front of the PIR sensors (3, 4) which is transparent to infrared radiation, wherein the housing (2) has a detection zone (7) for reducing the detection range (8) in each case between one of the PIR sensors (3, 4) and the viewing window (5) of the PIR sensor (3, 4), 4), characterised in that in each case a viewing window (5) is in front of an associated PIR sensor (3, 4) and in that the detection zone (7) is a slot-shaped tunnel (6) in the housing (2), so that a viewing window (5) and a slot-shaped tunnel (6) are arranged in front of each PIR sensor (3, 4), the slot-shaped tunnel (6) having an IR-absorbing surface of the tunnel walls and extending with its tunnel walls adjacent to the respective viewing window (5) towards the respective PIR sensor (3, 4) and limits IR radiation incident through the viewing window (5) in such a way that the infrared radiation strikes the sensitive surface (9) of the PIR sensor (3, 4) at a 90° angle with a tolerance deviation of up to +/- 20° and the reflection of laterally incident IR radiation within the housing (2) is reduced.
2. Device (1) according to claim 1, characterised in that a pair of PIR sensors (3, 4) are spaced from each other in the direction of passage.
3. Device (1) according to one of the preceding claims, characterised in that the detection area (8) of the first PIR sensor (3) and/or of the second PIR sensor (4) is restricted by the detection zone (7) in the direction of passage.
4. Device (1) according to one of the preceding claims, characterised in that the detection range (8) of the first PIR sensor (3) and/or of the second PIR sensor (4) is extended upwards in the vertical direction by the detection zone (7).
5. Device (1) according to one of the preceding claims, characterised in that the detection range (8) of the first PIR sensor (3) and/or of the second PIR sensor (4) is restricted downwards in the vertical direction by the detection zone (7).
6. Device (1) according to one of the preceding claims, characterised in that the housing (2) has thermal insulation.
7. Device (1) according to one of the preceding claims, characterized in that the housing (2) comprises an infrared-absorbing material.
8. Device (1) according to any one of the preceding claims, characterised in that the device (1) has a communication unit for wireless data communication.

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