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Passive IR motion sensors: current state, problems and development prospects. Motion sensor Principle of operation of active IR detectors

In the 21st century, everyone is familiar with IR sensors - they open doors at airports and shops when you walk up to the door. They also detect movement and give an alarm in the burglar alarm. Currently, passive optical-electronic infrared (IR) detectors occupy a leading position in the choice of protection of premises from unauthorized intrusion at security facilities. Aesthetic appearance, ease of installation, configuration and maintenance often give them priority over other detection tools.

Passive optical-electronic infrared (IR) detectors (they are often called motion sensors) detect the fact of a person entering the protected (controlled) part of the space, generate an alarm signal and, by opening the contacts of the executive relay (monitoring station relay), transmit an “alarm” signal to the warning means . As a means of warning, terminal devices (UO) of notification transmission systems (SPI) or a fire and security alarm control device (PPKOP) can be used. In turn, the above devices (UO or PPKOP) broadcast the received alarm notification via various data transmission channels to the central monitoring station (CMS) or the local security console.

How PIR motion sensor works

The principle of operation of passive optical-electronic IR detectors is based on the perception of a change in the level of infrared radiation of the temperature background, the sources of which are the body of a person or small animals, as well as all kinds of objects in their field of vision.

In passive optical-electronic IR detectors, infrared thermal radiation enters the Fresnel lens, after which it is focused on a sensitive pyroelement located on the optical axis of the lens (Fig. 1).

Passive IR detectors receive infrared energy flows from objects and are converted by a pyro receiver into an electrical signal, which is fed through an amplifier and a signal processing circuit to the input of an alarm generator (Fig. 1)1.

In order for the intruder to be detected by the IR passive sensor, the following conditions must be met:

Passive IR sensors consist of three main elements:

spatial zone

Depending on the design of the Fresnel lens, passive optical-electronic IR detectors have different geometric dimensions of the controlled space and can be either with a volumetric detection zone, or with a surface or linear one. The range of action of such detectors lies in the range from 5 to 20 m. The appearance of these detectors is shown in fig. 2.

Optical system

Modern IR sensors are characterized by a wide variety of possible beam patterns. The sensitivity zone of IR sensors is a set of rays of various configurations, diverging from the sensor in radial directions in one or more planes. Due to the fact that IR detectors use dual pyro receivers, each beam in the horizontal plane is split into two:

The detector sensitivity zone can look like:

The diversity and complex configuration of the forms of the sensitivity zone are primarily due to the following factors:

small rooms

long corridors

It is expedient to dwell on the requirement of uniform sensitivity in more detail. The signal at the output of the pyro receiver, all other things being equal, is the greater, the greater the degree of overlapping by the violator of the detector sensitivity zone and the smaller the beam width and the distance to the detector. To detect an intruder at a large (10...20 m) distance, it is desirable that the beam width in the vertical plane does not exceed 5°...10°, in which case the person almost completely blocks the beam, which ensures maximum sensitivity. At shorter distances, the sensitivity of the detector in this beam increases significantly, which can lead to false alarms, for example, from small animals. To reduce uneven sensitivity, optical systems are used that form several inclined beams, while the IR detector is installed at a height higher than human height. The total length of the sensitivity zone is thus divided into several zones, and the beams “nearest” to the detector are usually made wider to reduce sensitivity. This ensures almost constant sensitivity over the distance, which, on the one hand, helps to reduce false positives, and, on the other hand, increases the detectability by eliminating dead zones near the detector.

When building optical systems of IR sensors, the following can be used:

Typically, each segment of a Fresnel lens forms its own beam pattern. The use of modern lens manufacturing technologies makes it possible to ensure almost constant detector sensitivity for all beams by selecting and optimizing the parameters of each lens-segment: segment area, tilt angle and distance to the pyroelectric receiver, transparency, reflectivity, degree of defocusing. Recently, the technology of manufacturing Fresnel lenses with complex precise geometry has been mastered, which gives a 30% increase in the collected energy compared to standard lenses and, accordingly, an increase in the level of a useful signal from a person at long distances. The material from which modern lenses are made protects the pyroelectric receiver from white light. The unsatisfactory operation of the IR sensor can be caused by such effects as heat fluxes resulting from heating of the electrical components of the sensor, the ingress of insects on sensitive pyro-receivers, and possible re-reflections of infrared radiation from the internal parts of the detector. To eliminate these effects in the latest generation of IR sensors, a special hermetic chamber is used between the lens and the pyro receiver (sealed optics), for example, in new IR sensors from PYRONIX and C&K. According to experts, modern high-tech Fresnel lenses are almost as good as mirror optics in terms of their optical characteristics.

Mirror optics as the only element of an optical system is rarely used. IR sensors with mirror optics are available, for example, from SENTROL and ARITECH. The advantages of mirror optics are the possibility of more accurate focusing and, as a result, an increase in sensitivity, which makes it possible to detect an intruder at long distances. The use of several specially shaped mirrors, including multi-segment ones, makes it possible to provide an almost constant distance sensitivity, and this sensitivity at long distances is approximately 60% higher than for simple Fresnel lenses. With the help of mirror optics, it is easier to protect the near zone located directly under the sensor installation site (the so-called anti-tamper zone). By analogy with interchangeable Fresnel lenses, IR sensors with mirror optics are equipped with replaceable detachable mirror masks, the use of which allows you to select the desired shape of the sensitivity zone and makes it possible to adapt the sensor to various configurations of the protected premises.

Modern high quality IR detectors use a combination of Fresnel lenses and mirror optics. In this case, Fresnel lenses are used to form a sensitivity zone at medium distances, and mirror optics are used to form an anti-sabotage zone under the sensor and to provide a very large detection distance.

Pyro receiver:

The optical system focuses IR radiation on a pyro-detector, which is used in IR sensors as an ultra-sensitive semiconductor pyroelectric converter capable of registering a difference of several tenths of a degree between the temperature of the human body and the background. The change in temperature is converted into an electrical signal, which, after appropriate processing, triggers an alarm. In IR sensors, dual (differential, DUAL) pyroelements are usually used. This is due to the fact that a single pyroelectric element reacts in the same way to any change in temperature, regardless of whether it is caused by the human body or, for example, heating a room, which leads to an increase in the frequency of false alarms. In the differential circuit, the signal of one pyroelectric element is subtracted from another, which makes it possible to significantly suppress interference associated with changes in the background temperature, as well as significantly reduce the effect of light and electromagnetic interference. The signal from a moving person appears at the output of the dual pyroelectric element only when the person crosses the beam of the sensitivity zone and is an almost symmetrical bipolar signal, close in shape to the period of a sinusoid. For this reason, the beam itself for a dual pyroelement splits into two in a horizontal plane. In the latest models of IR sensors, in order to further reduce the frequency of false positives, quadruple pyroelements (QUAD or DOUBLE DUAL) are used - these are two dual pyro receivers located in one sensor (usually placed one above the other). The observation radii of these pyro receivers are made different, and therefore the local thermal source of false alarms will not be observed in both pyro receivers simultaneously. At the same time, the geometry of the location of the pyroelectric receivers and the scheme of their inclusion are chosen in such a way that the signals from a person are of opposite polarity, and electromagnetic interference causes signals in two channels of the same polarity, which leads to the suppression of this type of interference. For quad pyroelectric elements, each beam is split into four (see Fig. 2), and therefore the maximum detection distance when using the same optics is approximately halved, since for reliable detection, a person must block both beams from two pyro receivers with his height. To increase the detection distance for quad pyroelements allows the use of precision optics that form a narrower beam. Another way to correct this situation to some extent is the use of pyroelements with complex interlaced geometry, which is used by PARADOX in its sensors.

Signal processing unit

The signal processing unit of the pyro receiver must ensure reliable recognition of a useful signal from a moving person against the background of interference. For IR sensors, the main types and sources of interference that can cause false alarms are:

The selection by the processing unit of the useful signal against the background of interference is based on the analysis of the signal parameters at the output of the pyro receiver. These parameters are the magnitude of the signal, its shape and duration. The signal from a person crossing the beam of the IR sensor sensitivity zone is an almost symmetrical bipolar signal, the duration of which depends on the speed of the intruder, the distance to the sensor, the width of the beam, and can be approximately 0.02 ... ,1…7 m/s. Interference signals are mostly asymmetric or have a duration different from useful signals (see Fig. 3). The signals shown in the figure are very approximate, in reality everything is much more complicated.

The main parameter analyzed by all sensors is the magnitude of the signal. In the simplest sensors, this recorded parameter is the only one, and its analysis is performed by comparing the signal with a certain threshold, which determines the sensitivity of the sensor and affects the frequency of false alarms. In order to increase resistance to false alarms, simple sensors use a pulse counting method, when it counts how many times the signal exceeded the threshold (that is, in fact, how many times the intruder crossed the beam or how many beams it crossed). In this case, the alarm is generated not when the threshold is exceeded for the first time, but only if, within a certain time, the number of exceedances becomes greater than the specified value (usually 2…4). The disadvantage of the pulse counting method is the degradation of sensitivity, which is especially noticeable for sensors with a sensitivity zone such as a single curtain and the like, when the intruder can only cross one beam. On the other hand, when counting pulses, false alarms are possible due to repeated interference (eg electromagnetic or vibration).

In more complex sensors, the processing unit analyzes the bipolarity and symmetry of the waveform from the output of the differential pyro receiver. The specific implementation of such processing and the terminology used to refer to it1 may vary from manufacturer to manufacturer. The essence of processing is to compare a signal with two thresholds (positive and negative) and, in some cases, to compare the magnitude and duration of signals of different polarity. It is also possible to combine this method with separate counting of excesses of positive and negative thresholds.

Signal duration analysis can be carried out both by a direct method of measuring the time during which the signal exceeds a certain threshold, and in the frequency domain by filtering the signal from the output of the pyro receiver, including using a “floating” threshold, depending on the frequency analysis range.

Another type of processing designed to improve the performance of IR sensors is automatic thermal compensation. Temperature range environment 25°С…35°С the sensitivity of the pyro-detector decreases due to the decrease in the thermal contrast between the human body and the background; with a further increase in temperature, the sensitivity increases again, but “with the opposite sign”. In the so-called "conventional" thermal compensation circuits, the temperature is measured, and when it rises, the gain is automatically increased. With "real" or "two-sided" compensation, an increase in thermal contrast is taken into account for temperatures above 25°C ... 35°C. The use of automatic thermal compensation ensures that the sensitivity of the IR sensor is almost constant over a wide temperature range.

The listed types of processing can be carried out by analog, digital or combined means. In modern IR sensors, digital processing methods are increasingly being used using specialized microcontrollers with ADCs and signal processors, which allows for detailed processing of the fine structure of the signal to better distinguish it from noise. Recently, there have been reports of the development of fully digital IR sensors that do not use analog elements at all.
As is known, due to the random nature of useful and interfering signals, processing algorithms based on the theory of statistical decisions are the best.

Other protection elements of IR detectors

In IR sensors designed for professional use, so-called anti-masking schemes are applied. The essence of the problem lies in the fact that conventional IR sensors can be disabled by an intruder by preliminary (when the system is not armed) gluing or painting over the input window of the sensor. To combat this way of bypassing IR sensors, anti-masking schemes are used. The method is based on the use of a special IR channel that is triggered when a mask or reflective barrier appears at a small distance from the sensor (from 3 to 30 cm). The anti-masking circuit operates continuously while the system is disarmed. When the fact of masking is detected by a special detector, a signal about this is sent from the sensor to the control panel, which, however, does not issue an alarm signal until it is time to arm the system. It is at this moment that the operator will be given information about the masking. Moreover, if this masking was accidental (a large insect, the appearance large object for some time near the sensor, etc.) and by the time the alarm was set to self-resolved, the alarm is not issued.

Another protective element that almost all modern IR detectors are equipped with is a tamper-evident contact sensor, which signals an attempt to open or tamper with the sensor housing. Tamper and masking sensor relays are connected to a separate security loop.

To eliminate IR sensor triggers from small animals, either special lenses with a dead zone (Pet Alley) from floor level to a height of about 1 m are used, or special methods signal processing. It should be borne in mind that special signal processing allows ignoring animals only if their total weight does not exceed 7 ... 15 kg, and they can approach the sensor no closer than 2 m. will help.

For protection against electromagnetic and radio interference, tight surface mounting and metal shielding are used.

Installation of detectors

Passive opto-electronic IR detectors have one remarkable advantage over other types of detectors. It is easy to install, configure and Maintenance. Detectors of this type can be installed both on a flat surface bearing wall as well as in the corner of the room. There are detectors that are placed on the ceiling.

A competent choice and tactically correct use of such detectors are the key to reliable operation of the device, and the entire security system as a whole!

When choosing the types and number of sensors to ensure the protection of a particular object, one should take into account the possible ways and means of penetration of the intruder, the required level of detection reliability; expenses for the acquisition, installation and operation of sensors; features of the object; performance characteristics of sensors. A feature of IR-passive sensors is their versatility - with their use it is possible to block from the approach and penetration of a wide variety of premises, structures and objects: windows, shop windows, counters, doors, walls, ceilings, partitions, safes and individual objects, corridors, room volumes. At the same time, in some cases, a large number of sensors will not be required to protect each structure - it may be sufficient to use one or more sensors with desired configuration sensitivity zones. Let us dwell on the consideration of some features of the use of IR sensors.

The general principle of using IR sensors is that the rays of the sensitivity zone should be perpendicular to the intended direction of movement of the intruder. The location of the sensor should be chosen in such a way as to minimize the dead zones caused by the presence of large objects in the protected area that block the beams (for example, furniture, indoor plants). If indoor doors open inwards, the possibility of masking the intruder should be taken into account. open doors. If dead zones cannot be eliminated, multiple sensors should be used. When blocking individual objects, the sensor or sensors must be installed so that the rays of the sensitivity zone block all possible approaches to the protected objects.

The range of permissible suspension heights specified in the documentation (minimum and maximum heights) must be observed. This applies in particular to directional patterns with inclined beams: if the height of the suspension exceeds the maximum allowable, then this will lead to a decrease in the signal from the far zone and an increase in the dead zone in front of the sensor, but if the suspension height is less than the minimum allowable, this will lead to a decrease in the range detection while reducing the dead zone under the sensor.

1. Detectors with a volumetric detection zone (Fig. 3, a, b), as a rule, are installed in the corner of the room at a height of 2.2–2.5 m. In this case, they evenly cover the volume of the protected room.

2. Placement of detectors on the ceiling is preferable in rooms with high ceilings from 2.4 to 3.6 m. These detectors have a denser detection zone (Fig. 3, c), and existing pieces of furniture affect their operation to a lesser extent.

3. Detectors with a surface detection zone (Fig. 4) are used to protect the perimeter, for example, non-permanent walls, door or window openings, and can also be used to limit the approach to any values. The detection zone of such devices should be directed, as an option, along the wall with openings. Some detectors can be installed directly above the opening.

4. Detectors with a linear detection zone (Fig. 5) are used to protect long and narrow corridors.

How to fool the IR detector

The initial drawback of the IR passive method of motion detection: a person must clearly differ in temperature from the surrounding objects. At a room temperature of 36.6º, no detector can distinguish a person from walls and furniture. Worse than that: The closer the room temperature is to 36.6º, the worse the sensitivity of the detector. Majority modern devices partially compensate for this effect by increasing the gain at temperatures from 30º to 45º (yes, the detectors also work successfully with a reverse drop - if the room is +60º, the detector will easily detect a person, thanks to the thermoregulation system, the human body will keep the temperature around 37º). So, at a temperature outside of about 36º (which is often found in southern countries), the detectors open doors very poorly, or, conversely, because of the extremely high sensitivity, they react to the slightest breath of wind.

Moreover, it is easy to block any object from the IR detector. room temperature(with a sheet of cardboard) or put on a thick coat and hat so that your arms and face do not stick out, and if you walk slowly enough, the IR detector will not notice such small and slow perturbations.

There are also more exotic recommendations on the Internet, such as a powerful IR lamp, which, if turned on slowly (with a conventional dimmer), will drive the IR detector off scale, after which you can walk in front of it even without a fur coat. Here, however, it should be noted that good IR detectors in this case will give a malfunction signal.

Finally, the most well-known problem with IR detectors is masking. When the system is disarmed, during the daytime during business hours, you, as a visitor, come to the right place (to the store, for example) and, catching the moment while no one is looking, block the IR detector with a piece of paper, seal it with an opaque self-adhesive film or fill it with spray paint. This is especially convenient for the person who works there himself. The storekeeper carefully blocked the detector during the day, climbed through the window at night, took everything out, and then removed everything and called the police - horror, they robbed, but the alarm did not work.

To protect against such masking, the following techniques are available.

real life

malice

2. Some control panel devices have a control algorithm when, after the detector is disarmed, it detects movement. That is, the absence of a signal is considered a malfunction until someone passes in front of the sensor and it gives a normal “there is movement” signal. This function is not very convenient, because all premises are often disarmed, even those that no one is going to enter today, but it turns out that in the evening, in order to put the premises back on guard, you will have to go into all the rooms where no one was there during the day, and wave your hands in front of the sensors - the control panel will make sure that the sensors are operational and will graciously allow you to arm the system.

3. Finally, there is a function called "near zone", which was once included in the requirements of the national GOST and which is often mistakenly called "anti-masking". The essence of the idea: the detector should have an additional sensor looking straight down, under the detector, or a separate mirror, or a special tricky lens, in general, so that there is no dead zone below. (Most detectors have a limited field of view and mostly look forward and 60 degrees down, so there is a small dead zone directly below the detector, at floor level about a meter from the wall.) It is believed that a cunning enemy will somehow be able to get into this dead zone and from there block (disguise) the lens of the IR sensor, and then brazenly walk around the room. In reality, the detector is usually installed in such a way that there is no way to get into this dead zone, bypassing the sensor's sensitivity areas. Well, maybe through the wall, but against criminals penetrating through the wall, additional lenses will not help.

Interference and false positives

When using passive optical-electronic IR detectors, it is necessary to keep in mind the possibility of false alarms that occur due to various types of interference.

Interference of thermal, light, electromagnetic, vibration nature can lead to false alarms of IR sensors. Despite the fact that modern IR sensors have a high degree of protection against these effects, it is still advisable to adhere to the following recommendations:

open window

sun rays

bright light

Thermal interference - due to the heating of the temperature background when exposed to solar radiation, convective air flows from the operation of radiators of heating systems, air conditioners, drafts.
Electromagnetic interference - caused by pickups from sources of electrical and radio emissions on individual elements of the electronic part of the detector.
Extraneous interference - associated with the movement of small animals (dogs, cats, birds) in the detection zone of the detector. Let us consider in more detail all the factors affecting the normal performance of passive optical-electronic IR detectors.

Thermal noise

This is the most dangerous factor, which is characterized by a change in the temperature background of the environment. The impact of solar radiation causes a local increase in the temperature of individual sections of the walls of the room.

Convective interference is caused by the influence of moving air flows, for example, from drafts with an open window, cracks in window openings, as well as during the operation of household heating appliances - radiators and air conditioners.

Electromagnetic interference

They occur when any sources of electrical and radio emission are turned on, such as measuring and household equipment, lighting, electric motors, radio transmitting devices. Strong interference can also be created from lightning discharges.

Extraneous interference

Small insects, such as cockroaches, flies, wasps, can be a peculiar source of interference in passive optical-electronic IR detectors. If they move directly along the Fresnel lens, a false alarm of this type of detector may occur. The danger is also represented by the so-called domestic ants, which can get inside the detector and crawl directly over the pyroelement.

Ways to improve IR sensors

For ten years already, almost all security IR detectors contain a sufficiently powerful microprocessor and therefore have become less susceptible to random interference. The detectors can analyze the repeatability and characteristic parameters of the signal, long-term stability of the background signal level, which made it possible to significantly increase the resistance to interference.

Infrared sensors, in principle, are defenseless against criminals behind opaque screens, but they are affected by heat flows from climate equipment and extraneous light (through a window). Microwave (radio) motion sensors, on the contrary, are capable of generating false signals, detecting movement behind radio-transparent walls, outside the protected premises. They are also more susceptible to radio interference. Combined IR + microwave detectors can be used both according to the "AND" scheme, which significantly reduces the likelihood of false alarms, and according to the "OR" scheme for especially critical premises, which practically eliminates the possibility of overcoming them.

IR sensors cannot distinguish little man from a big dog. There are a number of sensors in which the sensitivity to the movements of small objects is significantly reduced due to the use of 4-area sensors and special lenses. The signal from a tall person and from a low dog in this case can be distinguished with some probability. It must be well understood that it is, in principle, impossible to completely distinguish a crouching teenager from a Rottweiler standing on its hind legs. Nevertheless, the probability of false alarms can be significantly reduced.

A few years ago, even more complex sensors appeared - with 64 sensitive areas. In fact, this is a simple thermal imager with a matrix of 8 x 8 elements. Equipped with a powerful processor, such IR sensors are able to determine the size and distance to a moving warm target, the speed and direction of its movement - 10 years ago, such sensors were considered the height of technology for homing missiles, and now they are used to protect against banal thieves.

Mounting errors

A special place in an incorrect or wrong work passive optical-electronic IR detectors are occupied by installation errors when performing installation work for these types of devices. Let's pay attention to vivid examples of incorrect placement of IR detectors in order to avoid this in practice.

On fig. 6 a; 7 a and 8 a shows the correct, correct installation of the detectors. You just need to install them this way and nothing else!

In figures 6 b, c; 7 b, c and 8 b, c are options incorrect installation passive optical-electronic IR detectors. With this setting, it is possible to miss real intrusions into protected premises without issuing an "Alarm" signal.

Do not install passive optoelectronic detectors so that they are exposed to direct or reflected rays of sunlight, as well as the headlights of passing vehicles.
Do not point the detection zone of the detector at the heating elements of the heating and air conditioning systems of the room, at the curtains and curtains, which can fluctuate from drafts.
Do not place passive optical-electronic detectors near sources electromagnetic radiation.
Seal all openings of the passive optical-electronic IR detector with sealant from the product kit.
Destroy insects that are present in the protected area.

Currently, there is a huge variety of detection tools that differ in the principle of operation, scope, design and performance.

The right choice of a passive optical-electronic IR detector and its installation location is the key to reliable operation of the burglar alarm system.

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These security detectors are used to detect movement inside the protected premises, additional blocking of surfaces, passages, open areas, external perimeters. Otherwise they are also called Motion Sensor. Let's start with the classification. The detectors considered here are classified according to:

type of detection zone - volumetric, surface, linear
operating principle - infrared (IR), radio wave, ultrasonic.
execution - wall, ceiling, for outdoor, indoor installation

Any specific detector is simultaneously characterized by each of the indicated categories.

INFRARED DETECTOR (IR) VOLUME, PASSIVE

The detection zone is volumetric, see Figure 1. It should be noted that such a volumetric detection zone is inherent in a wall-mounted detector. Above - side view (vertical plane), below - top view (horizontal plane).

An alarm signal is generated when an object that has a temperature different from the room temperature crosses the sectors that determine the configuration and size of the detection zone. Therefore, the characteristics indicate - volumetric, infrared (ie thermal). And such detectors are called passive because they work only "on reception", without emitting anything. Accordingly, the execution is single-block. In fact, any infrared volume detector is passive.

INFRARED (IR) DETECTOR SURFACE, LINEAR

In addition to volume, security IR detectors can also have a surface detection zone "curtain", linear - "beam". Surface Burglar infrared sensor has a detection zone shown in Figure 2 (everything is similar to Figure 1). For the linear zone of the diagram, I do not give a beam - it is a beam, which is from above, which is from the side, approximately like the bottom of Figure 2.

The principle of operation of surface, linear infrared sensors is similar to IR volumetric detectors. In addition, a number of linear detectors have active principle actions, i.e. consist of two security blocks - emitter and receiver. An alarm signal will be generated by the receiver when a foreign object crosses the IR beam generated by the emitter.

Summing up what has been said about security infrared detectors, we note the following features, which can be attributed to disadvantages:

Security infrared sensor is critical to hardness load-bearing structure. If it is subject to vibrations it may generate false alarms. Security infrared (IR) sensors should be installed on permanent structures.
When in the detection zone of an infrared sensor of convection (thermal) flows or light sources of variable intensity, spontaneous triggering is also possible. When installing infrared volumetric sensors, the location of heaters and windows should be taken into account.
Any objects that are in the detection zone of the IR volumetric detector form behind them (from the side opposite to the detector) a "shadow zone", where detection of a moving object is impossible. As a consequence, for example rearranging furniture will cause a change in the configuration of the detection area. The way out is the use of IR volumetric detectors of the ceiling (according to the installation method) execution.
They can track animals in the detection zone. But there are volumetric sensors protected from this factor.
May react to ingested small insects. Exit - seal all inputs to the sensor, periodically carry out appropriate sanitation of the premises

When choosing the type of security infrared detector, one should take into account the opening angle of the detection zone (measured in degrees), the range of the infrared detector. Please note - the range of the infrared volumetric sensor is indicated along the main axis, it is less along the side axes. Also, if you plan to operate the infrared detector in unheated room, select the appropriate operating temperature range.

SECURITY RADIO-WAVE, ULTRASONIC DETECTORS

The detection zone is voluminous, a kind of continuous voluminous spindle. The principle of operation of volumetric radio wave and volumetric ultrasonic sensors is the same, based on the Doppler effect, namely, a sound or radio wave, reflected from a moving object, changes its frequency (or, if you like, length). Thus, these security volumetric detectors are also designed to detect movement inside the protected premises. I want to note that all security detectors considered here (infrared, radio wave, ultrasonic, volumetric, linear), having the appropriate climatic design, can be installed outdoors.

As the name implies, a radio wave security sensor emits and receives radio waves, and an ultrasonic volumetric detector emits ultrasound. Unlike IR security detectors, these are indifferent to light, heat, drafts, but, however, have their drawbacks:

first, the volumetric radio wave detector emits radio waves enough high frequency(about 1 GHz) for which walls, windows, doors are transparent. If the size of the detection zone of the radio wave volume sensor is chosen incorrectly, it will react to what is being done outside the protected premises. (Ultrasonic - no).
second, (concerns radio wave) possible interference with other electronic devices
thirdly, when several volumetric radio wave detectors are nearby, they can induce mutual interference. The way out is the use of devices with different frequency letters. But there are few letters, a large number of radio wave detectors cannot be placed nearby.
fourth, being in the same room with working detectors of these types, although not fatal, is not very useful. Exit - when people are constantly nearby, turn off the power to the sensors.
fifth, the surface detection zone is not formed.

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3.2. Passive infrared motion detectors

For protection interior spaces most widespread received passive IR motion detectors. They differ from each other mainly in the size of the detection zone and noise immunity.

The principle of operation of passive IR detectors is based on registering changes in the intensity of IR radiation that occurs when a thermal object, such as a person or a dog, moves in the detection zone of the device. The sensitive element of such a device is a pyroelement (pyroreceiver), on the surface of which, under the influence of IR radiation from any thermal object, an electric charge arises. To register the fact of movement of a thermal object in the detector using a multi-segment mirror, a multi-beam radiation pattern is formed, consisting of a plurality of detection beams directed at different angles and in different directions. The intersection of these rays by a thermal object leads to the impact of IR radiation pulses on the pyroelement and, as a result, the formation of electrical impulses by the latter. These pulses are amplified and processed by a detector that counts their number and the time interval between them. The values of these parameters determine

the noise immunity of the device and the range of detectable speeds of a moving thermal object (from 3 m/s for a fast running person to 0.3 m/s for a very slow movement). The detection beams form a detection zone, which determines the sensitivity of the device, i.e., the maximum distance at which a moving object is still reliably detected. Accurate geometric characteristics(configuration) detection zones are provided with multi-segment mirrors and an optical system on Fresnel lenses. Usage various types lenses allows you to change the configuration of the detection zone depending on the situation. Due to this, motion detectors have a universal application and are used to protect the volume of premises, places of concentration of valuables (museum exhibits, office equipment, etc.) and approaches to them, corridors, internal perimeters, passages between racks, window and door openings, floors, etc. The optical system, depending on the type of lenses used, makes it possible to obtain detection zones of the following types: volumetric, surface, and narrowly directed.

The volumetric zone (standard) is formed using lenses of the "wide angle" type and is a sector of 90-110 ° in size with detection beams that form several discrete detection zones: far, intermediate, near and lower. The number of detection beams in these zones is different.

When using lenses of the "horizontal curtain" type, a surface detection zone is formed. Such a zone has a "dead" area (a zone of uncertain detection) up to a height of 1 - 1.2 m from the floor level, which allows the use of detectors with a "horizontal curtain" type lens in rooms where there are pets.

The narrowly focused zone formed by the "vertical curtain" type lens allows the detectors to be used to protect narrow corridors.

To increase the detecting ability, some detectors use sensors based on two or four pyroelements. IN this case the detection beam consists of two (four) elementary beams, and a special scheme for switching on the sensitive areas of the pyro receiver and a signal processing method provide increased resistance of the device to illumination caused by radiation lighting fixtures(white lamps) and the sun, perceived as a hindrance.

The detectors are well protected from the effects of electrical discharges and electromagnetic radiation in the microwave range by a strong metal case that acts as a screen. LED indication is used for visual monitoring of the device's performance and the level of interference at the place of its installation. In some types of detectors, it is possible to remotely turn on / off the LED indicators via the alarm loop.

When motion, interference is detected, or when the device is opened, an alarm notification can be generated in two ways: by short circuiting (by increasing the current consumption) or breaking (by reducing the current consumption) of the alarm loop. An alarm notification is issued by closing/opening the alarm, burglary, and fault output relay contacts. An alarm message is issued within a few seconds, because the detector remembers the alarm signal.

Sometimes an IR motion detector is placed in the same housing with other types of detectors, for example, with a motion detector broken glass. This is possible due to the use of passive infrared detection in motion detectors, which does not interfere with and does not affect the operation of other devices.

3.2.1. XJ series motion detectors.

3.2.1. XJ series motion detectors

Motion detector XJ660T

Fig.3.5 Motion detector XJ660T

The C&K Sysytem (IntelliSense) passive infrared detector XJ660T is a compact, attractive and easy-to-install device (Fig. 3. 5). It is used to protect residential and industrial premises.

The XJ660T is a passive infrared detector with a detection area of 18x15 m. The detector is manufactured using a patented technology that virtually eliminates possible sabotage of the device.

XJ660T detector features:

> automatic pulse counting;

> combination of multi-segment mirror and Fresnel lens;

> adjustment of the characteristics of the detection zone depending on the height of the installation;

> temperature compensation;

> resistance to white light;

> the possibility of using lenses of various types.

The device is equipped with a lens of the type "wide

angle" (Fig. 3. 6) or a lens of the "vertical

curtain". It is possible to install a lens that provides protection against pets, it prevents the device from triggering when an object less than 1 m high moves.

Main Specifications of XJ660T

Passive Infrared ................................................ Dual Pyro

with adjustable sensitivity Detection zone size, m .............................................................. ............... 18x15

Rice. 3. 6. Detection zones of XJ660T detector

Operating voltage range, V .............................................. ..... 6-14

Output relays:

alarm relay, mA/V .............................................. ................. 100/30

intervention relay, mA/V .............................................. .......... 25 / 30

Resistance to white light at a distance of 2.4 m, not less than, cd ........ 20000

Operating temperature range, °C ....................................... from -18 to + 65

Overall dimensions, mm.............................................. .......... 130x70x60

To increase the detection zone of the detector, an additional swivel bracket type DT4SW is used. Thanks to great design, the device fits well into the interior of an apartment or office. The detector is certified by the Ministry of Internal Affairs of Russia.

Motion detector XJ413T

Reliable detection, adjustable sensitivity, compact modern design- all these characteristics are inherent in the passive infrared motion detector XJ413T from C&K Systems (Fig. 3. 7). The detector is intended for use inside residential premises and offices. It is easily mounted on a wall or in a corner of a room (see section 1. 4).

Fig.3.7. Motion detector XJ413T

XJ413T detector features:

> the size of the detection zone is 13x13 m;

> adjustable pulse counter;

> control of the lower zone;

> ease of installation;

> additional lenses;

> small dimensions;

> interference sensor;

> resistant to white light;

> resistant to radio interference.

The size of the detection zone of the detector is determined by the lens "wide angle" (Fig. 3. 8) and is 13x13 m. The control of the lower zone is carried out due to the greater density of rays directed downward. Dual PIR element with additional "horizontal curtain" lens

allows to avoid false operation of the device in rooms with pets. By changing the number of counting pulses, the detector can be adjusted to suit the environment. There is an intervention sensor (relay with normally open contacts) in the device case, which generates an alarm signal when the detector case is opened.

Main technical characteristics of the XJ413T instrument:

The size of the detection zone, m ............................................... ............ 13x13

Consumed current (with supply voltage + 12 V), mA...................... 20

Output relays:

alarm relay, mA/V .............................................. ................. 100/24

Resistance to white light at a distance of 3 m, not less than, cd .............. 20000

10-1000 MHz, V/m............................................... ................................. thirty

Overall dimensions, mm.............................................. ............ 73х57х40

The sensitivity of the device, normal or high, is set by a jumper on the board. The detection zone consists of double beams and has a far (22 beams), intermediate (7 beams) and near (4 beams), as well as a lower zone (2 beams). The device is mounted on the wall or in the corner of the room; it can be installed on the SMB-10 universal mounting hinge.

Rice. 3. 8. Detection zones of XJ413T detector

Motion detector XJ-450T

Rice. 3.9. Passive IR Motion Detector XJ450T

The passive infrared detector XJ450T from C&K Systems is made in a durable white plastic case (Fig. 3. 9). It provides reliable detection of moving objects that emit heat. Sensitivity and range adjustments allow the sensor to be quickly adjusted to specific application conditions. The device is intended for use in residential areas, offices and small businesses.

XJ450T detector features:

> adjustable detection range;

> control of the lower zone;

> adjustable sensitivity;

> insect protection;

> additional lenses;

> LED trip indication

A double passive infrared element with an additional lens of the "horizontal curtain" type (Fig. 3. 10) allows you to get rid of false positives of the detector when moving pets in the protected area. Using a special signal processing algorithm, potential sources of false signals are eliminated.

Rice. 3. 10. Detection zones of the XJ450T

anxiety, such as insects. The lower zone is controlled due to the dense multi-beam structure of the radiation pattern. The ability to adjust the position of the detector sensor vertically allows you to adjust the size of the detection zone of the device, which makes its use more flexible. Depending on the adjustment, the size of the detection zone can be 15x12 m or 10x12 m. The detector sensitivity is set by a jumper and has two levels: normal and high.

Main technical characteristics of the XJ450T instrument:

Detection zone size, m .......................................... 15x12 or 10x12

Supply voltage, V ............................................... ................ 10-14

Consumed current (with supply voltage + 12 V), mA...................... 20

Output relays:

intervention relay, mA/V .............................................. .......... 25 / 24

alarm relay, mA/V .............................................. ................. 100 / 24

Resistance to white light at a distance of 2.4 m, no more than, cd .......... 20000

Immunity to radio interference in the frequency range

10-1000 MHz, V/m............................................... .................................thirty

Operating temperature range, C .......................................... from 0 to +49

The detector is easily mounted on a wall or in a corner of a room. The detection zone consists of double beams and has a far (22 beams), intermediate (6 beams), near (3 beams), and also a lower (2 beams) zones.

By changing the number of pulses to be counted, the sensitivity of the detector can be adjusted to suit the environment. The SMB-10 mounting hinge can be used to install and configure the device.

The detector has a quality certificate for use in Russia.

Motion detectors MS-550/MS-550T

Passive IR detectors MS-550/MS-550T manufactured by S&K (IntelliSense) are designed for indoor use. These are devices of a high degree of reliability achieved through the use of a microprocessor. The detectors have a self-diagnostic mode and are also equipped with an operating mode indicator. The appearance of the devices is shown in fig. 3. 9. It is the same as the XJ405T detector.

Features of MS-550/MS-550T detectors:

> use of a double pyroelement;

> tight radiation pattern;

> microprocessor signal processing system;

> automatic temperature compensation;

> self-diagnosis;

> sensitivity adjustment;

> protection against penetration of insects;

> the mode of checking the configuration of the protected zone.

A double pyroelement and an optical system make it possible to obtain a detection zone measuring 15x12 m (Fig. 3. 10) with a double density of detection beams. The detector is resistant to false alarms in the presence of any number of cats or other small animals of the same size with a total weight of not more than 7 kg, as well as any number of randomly flying or caged birds in the room. Mice and rats also do not affect the operation of the detector.

An automatic check of the detector's performance is performed hourly. If a malfunction is detected, the test is repeated every 5 minutes. Errors during the test are indicated by a flashing LED. ode. Upon successful completion of the self-test carried out by automatically after power-up, or when the user starts the self-diagnostic mode, the detector enters the 10-minute mode of checking the configuration of the protected zone. In this mode, you can determine the exact configuration of the protected area by performing a test pass - each time you cross the edge of one of the detection beams, the LED will turn on.

Main technical characteristics of MS-550/MS-550T devices:

Supply voltage, V ............................................... ................ 10-14

Consumed current (with supply voltage + 12 V), mA...................... 20

Output relays:

intervention relay, mA/V .............................................. .......... 25/24

Alarm relay, mA/V .............................................. ................. 100/24

Resistance to white light, lux .............................................. ......... 6500

Immunity to radio interference in the range

frequencies 10-1000 MHz, V / m .............................. ........................ thirty

Operating temperature range, C .......................................... from 0 to +40

Overall dimensions, mm.............................................. ............ 90x44x45

Mass, g ............................................... ............................................. 85

The detector allows you to adjust the sensitivity using jumpers on the instrument's circuit board. There are three levels of sensitivity: high, normal and low.

The detector can be mounted on a wall or in a corner of a room at a height of 1, 2, 2, 3 or 3 m from the floor. In this case, it should be remembered that the protected area must be within the line of sight of the detector.

Rice. 3.10. Detection zones of the XJ450T

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Rice. 3.6. Detection zones of XJ660T detector

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Rice. 3.8. Detection zones of XJ413T detector

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Fig.3.5 Motion detector XJ660T

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Fig.3.7. Motion detector XJ413T

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3.2.2. Motion detector PIR700E.

3.2.2. Motion detector PIR700E

The PIR700E passive infrared detector is designed for installation in rooms up to 200 m2. It is installed on the wall or in the corner of the room. The operation of the detector is based on the use of a double pyroelement. Design features detectors allow it to be used in residential areas where there are pets. PIR700E detector features:

> effective protection against false alarms caused by radio interference;

> adjustment of the size of the detection zone in the vertical and horizontal planes;

> double pyroelement;

> opening protection;

> high sensitivity;

> small dimensions;

> filtering of the supply voltage from mains interference;

> possibility of installation in the corner of the room.

It is recommended to use an uninterruptible power supply to operate the detector. When using a "wide angle" lens (Fig. 3. 11) and installed at a height of 1.8 m, the detector allows you to control an area of 15x15 m in size. The use of additional lenses allows you to correct the sensor's radiation pattern (Fig. 3. 11). Lens use lens 817 The "horizontal curtain" type only makes sense if the detector is installed in a room where there are pets. Lens use lens 818 type "vertical curtain" is justified when the device is installed in a narrow corridor.

Rice. 3. 11. PIR700E detection zones

Main technical characteristics of the PIR700E detector:

Dimensions of the detection zone, m .............................................. ..... 15, 2x15, 2

Supply voltage, V ............................................... .............. 10, 6-16

Consumed current (with supply voltage + 12 V), mA...................... 23

Maximum installation height, m ............................................... ...... 3, 6

Alarm relay, mA/V .............................................. ...................... 100/24

Detector output ................................ normally closed relay contacts

Relay switching time, max, s...................................... ............. 3

Operating temperature range, C...................................... from -10 to + 50

Overall dimensions, mm.............................................. ........... 114x64x43

Mass, g ............................................... ................................................. 198

The detector is installed on the wall or in the corner of the room, the maximum installation height is 3.6 m. The detector goes into armed mode no earlier than 3 minutes after power is applied. This mode is indicated by the device's LED indicator lighting up. To turn off the LED, remove the jumper on the device board. When mounting the detector, it is not recommended to place it near heat sources such as otollinium radiators, heater, incandescent lamps and etc..

Rice. 3.11. PIR700E detection zones

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3.2.3. Outdoor motion detector LX-2AU.

3. 2. 3. Outdoor motion detector LX-2AU

Optex's LX-2AU passive infrared detector is a device specially designed for outdoor use. The detector provides dimensional stability of the detection zone in the most severe climatic conditions such as snow, rain, fog, etc.

Features of the LX-2AU detector:

> automatic stabilization of the size of the detection zone in any environmental conditions;

> double pyroelement high sensitivity sensor;

> balanced temperature compensation;

> three levels of sensitivity;

> sensitivity adjustment;

> the built-in LED indicator of an operating mode;

> possibility to adjust the position of the sensor in the vertical and horizontal plane;

> quick resizing of the detection zone.

The sensor is resistant to direct sunlight and car headlights. A special signal processing algorithm allows it to adapt to changing environmental conditions. Main technical characteristics of the LX-2AU device:

The size of the detection zone, m ............................................... ............ 12x14

Viewing angle, hail .............................................. .............................. 120

Recorded travel speed, m/s .................................. from 0.3 to 1.0

Adjustment:

in the vertical plane, degrees .............................................. .......±45

in the horizontal plane, degrees .............................................. .0 - 20

Output relay, mA/V .............................................. ................... 100/24

Number of sensitivity levels ............................................................... ... 3

Operating temperature range, °С ....................................... from -20 to + 50

The built-in photodiode allows the sensor to automatically turn off at a certain level of illumination, usually during daylight hours. The light level at which this switch-off occurs is adjustable.

The sensor is easy to use and install. Ceiling and wall brackets allow you to adjust the position of the sensor in the vertical and horizontal plane.

3.2.4. Motion detectors "Photon".

3. 2. 4. Motion detectors "Photon"

Passive infrared detectors "Photon-6" and "Photon-8"

Security passive infrared detectors "Photon-6" and "Photon-8" designed and manufactured in Russia. They are designed to work as part of control panels, such as " Signal- 37A", "Signal-40", "Signal-45", as well as in the Phobos, Neva-10M systems, "Kometa-K".

The devices are powered by an alarm loop. A double pyroelement is used as a sensor. Through the use of three types

lens detectors have three detection zones. The housing of the devices has a modern design (Fig. 3. 12), which allows them to fit well into the interior of any room.

Features of "Photon" type detectors:

> high detecting ability;

> high resistance to electromagnetic, thermal and light interference;

> two ways to generate an alarm notification;

> quick access to the operating mode;

> visual control of device performance;

> supply voltage control;

> power supply via the signaling loop;

> wide installation possibilities.

The high detecting ability of the detectors is ensured through the use of three detection zones: volumetric, surface and linear (Fig. 3: 13). This allows them to be used to protect premises of almost any configuration.

Rice. 3. 13. Detector detection zones "Photon-6"

Main technical characteristics of detectors "Photon":

Controlled area with volumetric detection zone, m2 ............... 120

Recorded travel speed, m/s .............................. 0, 3-3, 0

Current consumption:

"Photon-6", mA................................................. ............................ 15

« Photon-8", mA................................................. ............................. 1

Operating temperature range:

"Photon-6",°С................................................. ............. -30 to + 50

"Photon-8",°С................................................. ............. -10 to + 50

Overall dimensions, mm.............................................. ......... 107x107x64

Weight, kg ............................................... ......................................... 0.25

Motion Detector "Photon-SK"

Security volumetric optical-electronic motion detector "Photon-SK"(Fig. 3. 14) is produced in Russia. It was developed jointly with the American company C&K Systems by order of the Main Directorate of Private Security of the Ministry of Internal Affairs of Russia. The sensor is recommended for installation in residential premises, offices and small businesses.

Detector Features Foton-SK:

> turn off the LED indicator in armed mode;

> protection against unauthorized opening;

> high noise immunity;

> protection from pets;

> minimum number of components;

> possibility of installation on a wall or in a corner of the room.

The device is currently "Photon-SK" is one of the cheapest motion detectors on the market. Russian market. In the manufacture of the device, modern technological equipment for surface mounting by Universal Instruments Corporation is used, which makes it possible to obtain very high device characteristics.

The detector has five detection zones and covers an area of 15x12 m

(Fig. 3.15). Digital signal processing makes it possible to exclude the sensor from flying insects. An additional lens allows you to limit the detection area from below to a certain height, thus providing protection from pets.

Rice. 3. 15. Device detection zones "Photon-SK"

Main technical characteristics of the device Foton-SK:

The size of the detection zone, m ............................................... ............ 15x12

Supply voltage, V ............................................... ................ 10-14

Consumed current, mA .............................................. ......................... 20

Operating temperature range, ° С ....................................... from -18 to + 49

Overall dimensions, mm.............................................. ............ 90x64x41

Mass, g ............................................... ............................................. 85

"Photon-SK" - this is one of the best detectors produced by the domestic industry. It has the highest quality/price ratio.

Rice. 3.12. Motion detector "Photon-SK"

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Rice. 3.12. Motion detectors "Photon-6" and "Photon-8"

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Rice. 3.13. Detection zones of the "Photon-6" detector

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Rice. 3.15. Detection zones of the Foton-SK device

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3.2.5. Motion detector MRS 4040T.

3. 2. 5. Motion detector MRS 4040T

The passive infrared detector MPC 4040T with a double sensitive sensor manufactured by IntelliSense is an economical device with a detection zone size of 12x15 m (Fig. 3. 16). It uses patented technology C&K, as well as a combination of a segmented mirror and a Fresnel lens, which practically eliminates the possible sabotage of the device.

Features of the MPC 4040T detector:

> temperature compensation;

> sensitivity adjustment;

> adjustment of the detection zone depending on the installation height;

> resistance to white light;

> additional swivel bracket.

Rice. 3. 17. Detection zones of the MPC4040T device

The device uses a double pyroelement with adjustable sensitivity. When using a "wide angle" lens (Fig. 3. 17), the area controlled by the device will be 144 m2 (12x12 m). A “vertical curtain” lens can be installed, which provides a narrow guarded area up to 18 m long. wide and narrow beam patterns.

The main technical characteristics of the MPC4040T device:

The size of the detection zone, m ............................................... ............ 12x 12

Immunity to radio interference at a distance of 3 m

in the range of 20-100 MHz, W .............................................. ................. 100

Resistance to white light at a distance of 2.4 m, not less, cd ......... 20000

Supply voltage, V ............................................... ................. 8-14

Consumed current (with supply voltage + 12 V), mA...................... 20

Output relays:

alarm relay, mA, V .............................................. ................. 100/30

Operating temperature range, C...................................... from -18 to + 65

Overall dimensions, mm.............................................. ............ 92x60x50

Mass, g ............................................... ............................................. 71

The sensor is mounted on a wall or in the corner of a room. An optional swing arm type DT4SW can be used for installation. The detector is intended for the protection of enclosed spaces. High quality and the moderate price of the device is just what makes it competitively capable of domestic market technical means protection.

IntelliSense's IQ200 series PIR motion detectors use a combination of four adjustable sensitivity pyroelectric elements. Devices (fig. 3.18) are intended for the organization of protection and installation in residential premises, offices and small businesses. The IQ220T has a range of 12m and the IQ260T has a range of 18m. Features of 10200 series detectors:

> the ability to adjust the size of the detection zone;

> LED indication of operating mode;

> resistance to radio interference;

> resistance to white light;

> temperature compensation.

The IQ220T features patented technology C&K, due to which false alarms of the system are almost completely excluded. The multi-segment mirror and Fresnel lens provide a detection area of about 200 m2. Using a set of lenses, you can get the required radiation pattern of the detector (Fig. 3.19). The device can be equipped with a "horizontal curtain" lens to protect against false alarms caused by pets. The detector contains two double pyroelements with adjustable sensitivity.

The main technical characteristics of the IQ200 series instruments:

Detection area size:

IQ220T,M.............................................. ................................. 12x12

IQ260T, m............................................... ................................. 18x15

Immunity to radio interference at a distance of 3 m

in the range of 27-1000 MHz, W .............................................. ................ 100

Resistance to white light at a distance of 2.4 m, cd ....................... 20000

Supply voltage, V ............................................... ................ 10-14

Consumed current (with supply voltage +12 V), mA......................30

Output relays:

alarm relay, mA/V .............................................. ................. 100/30

intervention relay, mA/V .............................................. .......... 25/30

Operating temperature range, °C ....................................... from -18 to +65

Overall dimensions, mm.............................................. .......... 130x70x60

Mass, g ............................................... ...................................... 227

3.2.7. Ceiling detector FIR5030.

3. 2. 7. Ceiling detector FIR5030

Motion detector FIR5030 from C&K (IntelliSense) is two independent devices in one housing: a passive infrared detector and a broken glass detector. FIR5030 has an omnidirectional pattern and is intended for installation on the ceiling of a protected area. It has a modern design (fig. 3. 20) and high performance characteristics, which makes it an excellent tool for protecting premises, for example small shops with a glass facade or offices. FIR5030 detector features:

> possibility of mounting flush with the ceiling surface and on a suspended ceiling;

> two output relays in one housing (one for each detector);

> adjustable height installation;

> sensitivity adjustment;

> LED indicator of operating mode;

> alarm memory.

The device includes a passive infrared (PIR) detector with a circular pattern based on a pyroelectric element with adjustable sensitivity. It is designed to detect unauthorized entry into the premises. One of two interchangeable mirrors can be used in it, the use of which is determined by the height of the device installation and the required number of detection beams (Fig. 3. 21).

When installing a mirror. No. 1 installation height should be from 2.5 to 3.5 m from the floor. In this case, the radiation pattern will consist of 77 detection beams of various lengths.

When installing mirror No. 2, the installation height should be 3.5-4.9 m. The number of detection beams is reduced to 61.

The second detector of the device is a broken glass detector (DBS) Flex Guard

with a range of up to 9 m, designed to register the fact of breaking glass and generate an alarm. The principle of operation of the detector is based

on spectrum analysis sound signal arising from impact with glass

and when breaking it. To generate an alarm, the instrument must

between both sounds should be no more than 150 ms. This eliminates the possibility of false positives. The range of the broken glass detector depends on the type, thickness and size of the glass. Therefore, to set up the device, it is necessary to use a special glass breaking simulator. FlexGuard 700..

Specifications of the FIR5030 detector:

Radius of detection zone of PIR detector, m ..............................................15

The number of detection beams is not less than .............................................. .............61

Installation height, m .............................................. ............. 2.5 to 4.9

DBS detection radius no more than, m .............................................. ....... 9

Glass type .............................................................. metallized, layered

tempered, reinforced Glass thickness, mm ....................................................... ............................... 4 - 7

Glass size not less than, mm .............................................. ........... 270x270

Supply voltage, V ............................................... .............. 8.5-1.6

Consumed current (with supply voltage +12 V), mA......................40

Output relays:

PIR detector alarm relay, mA/V....................................... 500/30

alarm relay DBS, mA/V....................................... ............ 500/30

intervention relay, mA/V .............................................. .......... 25 /30

Rice. 3. 21. Detection zones of the FIR5030 detector

The device can be installed on the ceiling surface or flush with it. Mounting height is adjustable with an additional mirror. The device provides the ability to adjust the sensitivity of the PIR detector and DBS and memorize the alarm signal.

Infrared detectors are one of the most common in burglar alarm systems. This is explained by a very wide range of their application.

They are used:

to control the internal volume of the premises;
organization of perimeter protection;
blocking various building structures "on the way".

In addition to the climatic version (outdoor and indoor installation), they are also divided according to the principle of operation. There are two large groups: active and passive. In addition, infrared detectors are divided according to the type of detection zone, namely:

voluminous;
linear;
superficial.

Let's look in order for what purposes one or another of their types are used.

Passive infrared detectors.

These sensors incorporate a lens that "cuts" the controlled area into separate sectors (Fig. 1). The detector is triggered when temperature differences between these zones are detected. Thus, the opinion that such a security sensor reacts purely to heat is erroneous.

If a person in the detection zone stands motionless, the detector will not work. In addition, the temperature of the object, which is close to the background temperature, also affects its sensitivity downward.

The same applies to cases when the speed of movement of the object is lower or higher than the normalized value. As a rule, this value is in the range of 0.3-3 meters/second. This is enough to reliably detect the intruder.

Active infrared detectors.

Devices of this type are composed of an emitter and a receiver. They can be made in separate blocks or combined in one body. IN last case when installing such a security device, an element that reflects IR rays is additionally used.

The active principle of operation is typical for linear sensors that are triggered when the infrared beam is crossed. Below are the principles of operation and features of the use of the main types of IR detectors.

VOLUME INFRARED DETECTORS

These devices are passive (see above for what it is) and are used mainly to control the internal volume of premises. The radiation pattern of the volumetric sensor is characterized by:

opening angle in vertical and horizontal planes;
range of the detector.

Please note - the range is indicated by the central lobe of the diagram, for the side ones it will be less.

What is typical for any infrared sensor, including a volumetric one, is that any obstacle is opaque for it, and accordingly creates dead zones. On the one hand, this is a disadvantage, on the other hand, an advantage, since there is no reaction to moving objects outside the protected premises.

Also, the disadvantages include the possibility of false positives from such factors as:

convection heat flows, for example, from heating systems of various operating principles;
flare from moving light sources - most often car headlights through the window.

Thus, when installing a volumetric detector, these points cannot be ignored. According to the method of installation, there are two versions of "volumizers".

Wall mounted IR detectors.

Ideal for offices, apartments, private houses. In such rooms, furniture and other interior items are usually located along the walls, so there are no blind spots. If we take into account that the horizontal viewing angle of such sensors is about 90 degrees, then by installing it in the corner of a room, one device can almost completely block a small room.

Ceiling volume detectors.

For objects such as shops or warehouses, a characteristic feature is the installation of shelving or showcases throughout the area of the premises. The installation of a ceiling sensor in such cases is more effective, of course, if these elements have a height below the ceiling.

Otherwise, you will have to block each formed compartment. In fairness, it should be noted that such a need does not always arise, but these are the subtleties of signaling design for each specific object, taking into account all its individual features.

LINEAR INFRARED DETECTORS

By their principle of operation, they are active and form one or more beams, tracking their intersection by a possible intruder. Unlike volumetric sensors, linear sensors are resistant to various kinds of air currents, and direct illumination, in most cases, will not harm them.

The principle of operation of a linear single-beam infrared emitter is illustrated in Figure 2.

The range of active linear devices is from tens to hundreds of meters. The most typical options for their use:

corridor blocking;
protection of open and fenced perimeters of the territory.

To protect the perimeter, detectors with more than one beam are used (it is better if there are at least three of them). This is fairly obvious as it reduces the chance of penetration below or above the control zone.

When installing and configuring infrared linear detectors, precise alignment of the receiver and transmitter is required for two-unit devices or reflector and combined unit (for single-unit). The fact is that the cross section (diameter) of the infrared beam is relatively small, so even a small angular displacement of the transmitter or receiver leads to its significant linear deviation at the receiving point.

From what has been said, it also follows that all elements of such detectors must be mounted on rigid linear structures that completely exclude possible vibrations.

I must say that a good "linear" is a rather expensive pleasure. If the cost of single-beam devices with a short range still lies within a few thousand rubles, then with an increase in the controlled range and the number of IR rays, the price increases to tens of thousands.

This is explained by the fact that security detectors of this type are quite complex electromechanical devices containing, in addition to electronics, high-precision optical devices.

By the way, passive linear detectors also exist, but in terms of maximum range they are noticeably inferior to their linear counterparts.

OUTDOOR INFRARED DETECTORS

It is quite obvious that an outdoor burglar alarm detector must have an appropriate climatic design. This applies primarily to:

operating temperature range;
degree of dust and moisture protection.

According to the generally accepted existing classification, the protection class of a street detector must be at least IP66. By and large, for most consumers, this is not important - it is quite enough to indicate "street" in the description technical parameters device. It is worth paying attention to the temperature range.

Of greater interest are the features of the use of such devices and factors affecting the reliability of protection.

By the nature of the detection zone, infrared security detectors designed for outdoor installation can be of any type (in descending order of popularity):

linear;
voluminous;
superficial.

As already mentioned, street linear detectors are used to protect the perimeter of open areas. Surface sensors can also be used for the same purposes.

Volumetric devices are used to control various kinds of areas. It should be immediately noted that in terms of range they are inferior to linear sensors. It is quite natural that the prices for outdoor detectors are much higher than for devices intended for indoor installation.

Now, with regard to the practical side of operation in burglar alarm systems of infrared outdoor detectors. The main factors that provoke false alarms of security sensors installed on the street are:

the presence of various vegetation in the protected area;
movement of animals and birds;
natural phenomena in the form of rain, snow, fog, etc.

The first point may seem unprincipled, since, at first glance, it is static and can be taken into account at the design stage. However, do not forget that trees, grass and bushes grow and over time can become a hindrance to normal operation security equipment.

Manufacturers try to compensate for the second factor by using appropriate signal processing algorithms, and there is an effect from this. True, whatever one may say, if an object even with small linear dimensions moves in the immediate vicinity of the detector, it will most likely be identified as an intruder.

As for the last point. Here everything depends on the change in the optical density of the medium. In simple terms, heavy rain, heavy snow or thick fog can make the infrared detector completely inoperative.

So, when deciding on the use of street security detectors in the alarm system, consider all that has been said. Thus, you can save yourself from many unpleasant surprises when operating an outdoor security system.

* * *

The site materials are for informational purposes only and cannot be used as guidelines or official documents.

1.3.1. Passive optoelectronic infrared (IR) motion sensors

To create a system, I decided to select modules that would be suitable for creating a system and monitoring the perimeter.

I chose the following components:

passive infrared motion sensor;
GSM module;
siren.

Let's consider them in more detail.

In the 21st century, everyone is familiar with IR sensors– they open doors at airports and shops when you walk up to the door. They also detect movement and give an alarm in the burglar alarm.

Currently, passive optical-electronic infrared (IR) detectors occupy a leading position in the choice of protection of premises from unauthorized intrusion at security facilities. Aesthetic appearance, ease of installation, configuration and maintenance often give them priority over other detection tools.

Passive optical-electronic infrared (IR) detectors(they are often called motion sensors or PIR sensors) detect the fact of human penetration into the protected (controlled) part of the space, form an alarm signal and, by opening the contacts of the executive relay (monitoring station relay), transmit the signal " anxiety» on alerts.

As a means of warning, terminal devices (UO) of notification transmission systems (SPI) or a fire and security alarm control device (PPKOP) can be used. In turn, the above devices (UO or PPKOP) broadcast the received alarm notification via various data transmission channels to the central monitoring station (CMS) or the local security console.

The principle of operation of passive optical-electronic IR detectors is based on the perception of a change in the level of infrared radiation of the temperature background, the sources of which are the body of a person or small animals, as well as all kinds of objects in their field of vision.

Sensor, sensitive to infrared radiation in the range of 5–15 µm, detects thermal radiation from human body. It is in this range that the maximum radiation from bodies at a temperature of 20–40 degrees Celsius falls.

The hotter an object is, the more it radiates.
infrared spotlights for backlighting video cameras, beam (two-position) detectors beam crossing” and TV remote controls operate in the wavelength range shorter than 1 micron, the human-visible region of the spectrum is in the region of 0.45–0.65 microns.

Passive sensors of this type are called because they themselves do not emit anything, they only perceive thermal radiation from the human body.

The problem is that any object at a temperature of even 0º C emits quite a lot in the infrared range. Worse, the detector itself emits - its body and even the material of the sensitive element.

Therefore, the first such detectors worked, if only the detector itself was cooled, say, to liquid nitrogen (-196º C). Such detectors are not very practical in everyday life.

That is, it is important that the radiation from a person is focused only on one of the sites, and, moreover, it changes.

The detector works most reliably if the image of a person first hits one area, the signal from it becomes greater than from the second, and then the person moves, so that his image will now fall on the second area and the signal from the second will increase, and the first will fall.

Such fairly rapid changes in signal difference can be detected even against the background of a huge and unstable signal caused by all other surrounding objects (and especially sunlight).

Rice. 1.

IN passive optical-electronic IR detectors infrared thermal radiation enters the Fresnel lens, after which it is focused on a sensitive pyroelectric element located on the optical axis of the lens.

Passive IR detectors receive infrared energy flows from objects and are converted by a pyro receiver into an electrical signal that enters through an amplifier and a signal processing circuit to the input of an alarm generator ( rice. 1).

In order for the intruder to be detected by the IR passive sensor, the following conditions must be met:

the intruder must cross the beam of the sensor's sensitivity zone in the transverse direction;
the movement of the intruder must occur in a certain range of speeds;
the sensitivity of the sensor should be sufficient to register the temperature difference between the surface of the intruder's body (taking into account the influence of his clothes) and the background (walls, floor).

an optical system that forms the radiation pattern of the sensor and determines the shape and type of the spatial sensitivity zone;
a pyro receiver that registers the thermal radiation of a person;
a signal processing unit of a pyro-receiver that distinguishes signals caused by a moving person against the background of interference of natural and artificial origin.

Rice. 2.

Depending on performance fresnel lens passive optical-electronic IR detectors have different geometric dimensions of the controlled space and can be both with a volumetric detection zone, and with a surface or linear one.

The range of such detectors lies in the range from 5 to 20 m. The appearance of these detectors is shown on rice. 2.

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