The intruder alarm system is mainly composed of an intruder alarm panel and intruder sensors, and intruder sensors play a front-end detection role in the intruder alarm system. Therefore, the stability of the performance of intruder sensors will directly affect the normal operation of the entire intruder alarm system. Over the years of research and development, issues such as false alarms, missed alarms, and interference have always been technical challenges that the intruder alarm industry needs to overcome. So intruder alarm manufacturers can only make every effort to reduce the probability of these problems occurring as much as possible through their own technological innovation, in order to gain user recognition.

In intruder alarm systems, the intruder alarm panel is relatively mature in technology and will be integrated into security systems in the future, combined with networking, wired and wireless integration, and other directions, without significant technological changes. There are many intrusion detection technologies, and there is a relatively large space for research and development. Therefore, the innovation of intruder alarm systems is mainly reflected in the technological transformation of intruder sensors. So intruder alarm manufacturers will focus on the research of intrusion detection technology as the focus of intruder alarm technology. After long-term technological research and integration by intruder alarm manufacturers, the intrusion detection technology in the market is developing in a diversified direction.

1 Diversified new detection technologies

(1) Multi beam technology

Among numerous detection technologies, infrared detection is the most common one. In active infrared detectors, the development of single beam technology has been difficult to meet people’s requirements for detectors. The active infrared detector technology mainly adopts one transmitter and one receiver, which belongs to linear prevention. At present, active infrared detectors have evolved from single beam to multi beam, which can effectively reduce false alarms and enhance the reliability of prevention. In order to expand the scope of prevention and overcome the shortcomings of ordinary active infrared radiation prevention, many intruder alarm manufacturers have developed multi beam grating active infrared radiation, which is actually an extension of single beam active infrared detection technology.

The active infrared detector emits and receives infrared beams, creating a safe protection area. Once an object blocks the infrared beam, the active infrared detector will detect an interruption in the infrared signal and give an alarm, playing a theft prevention role. However, a single beam of infrared radiation only has one set of rays, which limits the coverage range of the active infrared detector to a very small area. This gives criminals such as thieves the opportunity to commit crimes. Therefore, multi-beam technology with multiple sets of beams that can cross-beam from different directions and angles has been developed. This technology increases the coverage range of the beam and makes it more complex, greatly enhancing the security of prevention and effectively reducing the occurrence of false alarms and missed alarms.

(2) Anti-blocking, anti-spraying, and anti-pet detection technology

During operation, intruder sensors are often subject to intentional human destruction or interference from other objects entering, resulting in false or missed alarms. In response to this, various detection measures to avoid it have also been continuously developed. The most important technologies among them are anti-blocking, anti-spraying, and anti-pet technology.

Due to the fact that PIR motion sensors are usually based on passive infrared (PIR) technology that detects the radiation heat of intruders, they can easily be deceived by simply covering the sensor. The anti-blocking system is to trigger an alarm when the intruder sensor is covered or blocked. The advanced level of anti-blocking sensors has been further improved, even if transparent hair glue is sprayed on the lens, it will trigger an alarm. Therefore, a technology called “multi-point anti-blocking and integrated spray detection” can fully ensure the detection reliability of intruder sensors. It includes functions such as rearview metering, infrared receiver reflection, and integrated spray detection. The rearview metering function can prevent substances from flowing through the front of the sensor. The infrared receiver reflection function can prevent objects from approaching or obstructing the sensor. If detectors with anti-blocking technology are installed in places such as bank vaults, the robbers will not succeed easily.

False alarms caused by unconscious entry of animals such as cats, dogs, birds (even children) into the detection area often occur. To avoid such situations, anti-pet intrusion detection technology is specifically designed for small animals. For example, the “motion curve analysis” anti-pet detection technology specifically designed for this situation is mainly based on the different movement modes of humans (including adults and children) and small animals, and then analyzed by software. Micro processing technology is integrated into the intruder sensor, so that no matter where pets (below 40 kg) move, the intruder sensor will not alarm. This detection technology has made special treatments for special situations, thus preventing the occurrence of false alarms.

(3) Microwave wall technology

In the rapidly developing environment of science and technology, many new detection technologies are constantly emerging. In order to better adapt to different security levels of application places, intruder alarm manufacturers have come up with many methods, constantly innovating and improving their detection technologies to meet the needs of applications.

For high-risk protection areas such as power stations, prisons, military facilities, and high-risk industrial areas, intruder sensors need to have high stability and anti-false alarm capabilities. Therefore, microwave wall detectors are their best choice. The microwave wall includes independent transmitter and receiver units, installed face to face, with a maximum protection range not exceeding the allowable length. The microwave forms a solid fence, which can effectively prevent illegal intrusion. It can perform digital signal analysis on detection ranges below 200 meters. Reducing the possibility of false alarms caused by factors such as adverse weather and environmental changes is an effective guarantee for highly protected areas.

(4) Solar wireless detection technology

The rise and application of solar wireless infrared detection technology is another highlight of the development of detection technology. Solar wireless targeting utilizes solar energy for power supply, and signals are transmitted wirelessly without the need for additional power and signal cables, truly achieving full wireless operation. It largely solves the problem of construction and maintenance troubles. Its working principle is basically the same as traditional wired detectors, but the power of solar wireless detectors must be reduced, otherwise, the area of solar panels is too large to be conducive to production and use.

The solar infrared beam detector is equipped with a rechargeable lithium battery, and the power supply part is powered by solar panels. This way, solar energy can be recycled without the need to lay power cables. Generally speaking, solar panels are made of amorphous silicon, which can generate electricity without direct sunlight, greatly expanding the installation environment. In addition, the power supply capacity of the solar panel is much greater than the power consumption of the solar infrared beam detector, ensuring that it can work normally even in the absence of light at night and continuous cloudy and rainy days. Moreover, the solar infrared beam detector is equipped with a built-in wireless transmission module, and alarm signals are transmitted wirelessly. Under the premise of complying with relevant policies and regulations, high-power transmission modules should be used as much as possible to ensure effective wireless transmission distance between solar infrared beam detectors and intruder alarm panels. Therefore, the emergence of solar infrared beam detectors provides users with more choices.

2 Significantly improved detection sensitivity

The front lens of an intruder sensor directly affects the angle and distance of detection. In the past, infrared sensors mainly used traditional single beam PIR reflection focusing optical systems and multi beam lens focusing optical systems. These lenses often caused uneven infrared detection within the detection range, leading to false alarms. Currently, there is a technology based on “uniform and consistent infrared lenses” that solves the above problems. For example, the use of hemispherical lenses greatly improves the sensitivity imbalance caused by changes in the focal length, making it a new type of detection lens.

A single beam reflection focusing optical system utilizes a curved mirror to concentrate infrared radiation from a target onto an infrared sensor. The detection angle of this method is relatively narrow, generally below 5 °, but the effective distance is far, up to 100 meters. The multi beam Fresnel lens, on the other hand, has a multi-layer beam structure. This kind of lens is formed at once with special plastic, with several small lenses arranged on a curved surface. The warning range presents multiple single beam states in different directions, forming a three-dimensional fan-shaped heat sensing area, forming a three-dimensional warning. The Fresnel lens is divided into several rows from top to bottom, with more lenses on the top and fewer on the bottom. Its horizontal angle can be greater than 90 °, and the maximum vertical field of view angle can also reach 90 °. Its detection sensitivity is much higher than that of single beam reflector technology. However, due to the different focal lengths, Fresnel lenses still have uneven detection sensitivity.

In this regard, the traditional Fresnel lens uses a “standard lens, the wide-angle part of the lens looks at the distance, and the zoom part looks at the near.” Therefore, the installation height and detection distance have a significant impact on sensitivity, and there may be blind spots directly below the sensor. It is necessary to install with a bracket or configure bottom window protection. The use of hemispherical lenses can effectively solve the problem of sensitivity balance. Its superiority is mainly reflected in the fact that the detection objects at different distances of the hemispherical lens structure have equal focal lengths, which improves the problem of uneven sensitivity caused by changes in focal length in traditional standard lenses. In addition, within a certain radius range, spherical lenses with the same focal length cover a larger area than standard Fresnel lenses, with a detection angle of approximately 110 ° (instead of 90 ° for traditional sensors), and can completely avoid dead angles directly below the installation of intruder sensors. Therefore, the use of hemispherical mirrors has greatly improved the coverage, sensitivity, and reliability of intruder sensors.

3 Effective improvement of infrared sensing unit

In the detection process of infrared intruder sensors, the stability of the passive infrared sensing unit is one of the main standards for measuring the quality of infrared intruder sensors. In indoor intruder alarm systems, false alarms are often happened due to the susceptibility of infrared intruder sensors to changes in various air sources such as airflow. Or, due to the high temperature and enclosed environment in summer, the detection range may be shortened, resulting in missed alarms. Both of these situations are manifestations of the instability of infrared intruder sensors.

For a long time, the intruder alarm industry has always strived to strike a balance between detection performance and anti-false alarm. The result is that it often avoids false alarms but seriously affects detection performance. For example, the PIR motion sensor distinguishes intrusion based on the difference between indoor temperature and human body temperature, so it mainly uses room temperature as the standard. Once an intrusion occurs, the temperature difference in the defense area caused by human body temperature can be detected by infrared intruder sensors, which can easily increase the probability of false alarms. At present, a “dynamic temperature compensation” technology can basically solve this problem. It uses advanced algorithms to gradually reduce sensitivity when the room temperature is above or close to human body temperature. In this way, the infrared intruder sensor can detect intruders at any temperature while keeping the false alarm rate as low as possible. Temperature compensation technology effectively reduces the temperature sensing of infrared intruder sensors, greatly reducing false alarms.

In order to solve the problem of environmental impact on infrared intruder sensors, a company has designed and developed a “four-source pyroelectric infrared sensor “. This type of sensor is different from traditional “dual-source pyroelectric infrared sensor”. It can achieve high sensitivity for passive infrared detection in the detection area and analyze various interference source signals. When the “four-source pyroelectric infrared sensor” senses thermal motion changes in harsh environments, the system will send these signals containing the shape, duration, speed, and size of the detected object to the ASIC chip for processing and analysis. So as to make a correct judgment on whether the infrared sensing source should trigger an alarm. Therefore, this has greatly improved the accuracy of infrared intruder sensors and reduced false alarms.

In summary, in order to reduce the problem of false alarms and missed alarms in infrared intruder sensors, many industry professionals have made significant improvements to the infrared sensing unit to adapt to the impact of lighting, temperature, and other environments. This has further advanced the technology of sensors and taken a successful step forward.

4 The continuous upgrade of micro-processing chips

Micro-processing chips are another core component of intruder sensors. Due to the continuous development and progress of technology, upgraded intruder sensors such as intelligent and triple detection have integrated microprocessor chips. When the infrared or microwave induction unit is triggered, these related information needs to be sent to the microprocessor for analysis. However, due to the limited functionality of microprocessor chips, they can only perform basic information and algorithm judgments. At the same time, there are also many components on the intruder sensor motherboard, so the pressure on the microprocessor chip of the intruder sensor is constantly increasing.

In order to better ensure the stable and safe operation of intruder sensors, intruder alarm manufacturers have also begun to explore new integrated chips, and the development of the “brain – intelligent analysis unit” technology for intruder sensors is a new highlight. With the development of modern technology, the complexity of ASIC chip design has increased from 5000 NAND gates to 100 million NAND gates. The new generation of ASIC chips already includes “memory and signal processing units”, which can comprehensively and quickly analyze the relevant information sent by infrared or microwave induction units after being triggered. This provides a powerful functional support for intruder sensor lenses and upgraded sensor units to maximize their effectiveness, further reducing the probability of intruder sensor failures due to component issues. Through the use of this chip, the signal processing capability, optical design, temperature compensation, anti-interference, balanced sensitivity and capture performance of intruder sensors have been effectively improved, greatly improving detection performance.

5 Integrating multiple technologies

Due to the diverse types of intrusion detection technologies, intrusion detection technology has begun to move towards centralization. Detection equipment with “sensor data fusion” technology that has appeared on the market. It uses a complex set of algorithms to collect signals detected by the following five sensors: long-range and medium short range defense area PIR (providing double the detection signal and stronger detection ability), adaptive microwave Doppler radar system, white light intensity sensor, and room temperature sensor (providing “dynamic temperature compensation” function). This intruder sensor will process data from all sensors, thereby improving the performance of the intruder sensor.

The “sensor data fusion” system of this intruder sensor is based on complex algorithms, which can distinguish human features (body temperature characteristics, electromagnetic reflection characteristics) from the features of insects and small animals (such as cats and dogs). At the same time, it also has the ability to prevent insects and pets. In addition, the intruder sensor fully utilizes the “data fusion” algorithm as a whole. The microwave module used in its Doppler radar system is specially designed, with a customized microwave energy field that accurately covers the required area and the required sensitivity, enhancing the detection effectiveness.

6 Diversified design of product forms

With the constantly changing needs of users, many intruder alarm manufacturers have turned their attention to researching new forms of intruder sensors to meet the special needs of people for different types of products, under the premise of continuous improvement of detection technology.

Multi reflection passive infrared sensor is an intrusion detection product based on special user needs. This intruder sensor combines ultra black crystal reflective optical system, active infrared anti-blocking technology, array eight infrared sensing element processing technology, and narrow window technology. This intruder sensor uses eight independent quaternary infrared sensors arranged in an array. The central processor utilizes a new TMRTM digital algorithm to comprehensively analyze the cumulative time, amplitude, shape, size, movement speed and direction, as well as background temperature of the detected target. It can effectively distinguish moving humans from trees, shrubs, and small animals. It can also work normally under conditions such as rain, snow, fog, strong winds, and strong light. The intruder sensor adopts a dome shaped lens installation area and an embedded design, which can effectively reduce the interference of environmental factors such as light, and ensure the stability of the angle and direction required by active infrared anti-blocking technology, while also having higher resistance to damage. In addition, the intruder sensor also has anti-blocking and anti-spraying technology, and the black nickel coating on the lens can effectively resist white light interference. When exposed to strong light such as sunlight and headlights, it will not give false alarms. The intruder sensor has a long detection distance and a wide coverage area, which brings convenience to the use of intelligent communities.

In addition, an intruder sensor similar to a “lamp pillar type” can also effectively protect the owner’s intruder alarm protection needs. This type of sensor has a shape similar to a circular lamp pillar, with a very beautiful appearance and good concealment. It can not only be used for lighting, but also for safety protection. This type of intruder sensor can choose its own height according to user needs. It adopts a multi beam protection design, and users only need to install an intruder sensor around the villa, which can effectively weave an invisible cross infrared protection network, making it impossible for thieves and other criminals to steal. And this type of lamp pillar intruder sensor can also be designed to support solar energy, which is very suitable for user needs.

7 Intelligent detection technology needs further development

At present, the intelligent function of intruder sensors is not yet mature. What many intruder alarm manufacturers call intelligent detection actually only implements some intelligent functions. For example, some intelligent optical modules that can distinguish between small animals and people have appeared on the market, but the intruder sensor integrates some modules, and the truly intelligent intruder sensors still have not appeared.

In addition, intelligent intruder sensors should be said to have appeared, but the expected effect is still far from being achieved. This is mainly a contradiction between the technology and cost of intruder sensors. In the future, if we comprehensively consider and break through this bottleneck, we believe that the intruder alarm system will have a breakthrough.

For intelligent intruder sensors (using chip technology), although their technology has been improved, they still need to be installed carefully according to requirements, such as avoiding various interference sources, installation height, and position. All of these will affect the reliability and stability of intruder sensors. Therefore, intelligent intrusion detection technology still has a long way to go.

In summary, the intrusion detection technology of intruder alarm systems is rich and diverse, and the implementation methods are endless, which can weave an invisible security protection network for users. Users also have strong flexibility in their choices. And this is exactly what intruder alarm manufacturers hope to see. With the continuous deepening and development of technology, the diversification of intrusion detection technology will continue to extend. We believe that in the future, diverse intrusion detection technologies will be more closely integrated and will move towards a direction where more technologies are integrated.