Detector signal false positive/false negative and codec security issues

The core products of the wireless alarm system are the host and the detector. After receiving the alarm signal, the host will generate a high-decibel alarm sound, and at the same time, it will use the telecommunications network to call multiple groups of phones set by the owner to complete the alarm. However, in actual use and operation, wireless alarm products often have great safety hazards due to their own defects. Therefore, the core requirements of users for wireless alarm products are stability, safety and reliability. It is understood that the problems that affect the core requirements of wireless alarm system products are mainly concentrated in the following aspects. 
　　
　　Signal interference and strength problems
　　
　　Although the advantages of the wireless alarm system are outstanding, the disadvantages are also very obvious. During the transmission of the signal, it often encounters problems of signal interference and signal strength. The wireless alarm system is a working principle in which the detector sends the signal in the form of radio waves and the alarm host receives it to complete the alarm. However, the signal transmission between the alarm host and the detector is often affected by various external interferences, and the resulting instability occurs from time to time. Specifically, it is mainly concentrated on the problems of signal interference with the same frequency or other radio waves, channel blocking, signal strength, etc. 
　　
　　Zhang Yingyong, General Manager of Diwei Intelligent China, said that currently a considerable number of wireless detectors on the market do not report any other status information except alarm information. When the detector has a power failure, is removed, crashes, or other faults that affect the safety of the system, the host cannot detect it. The user can still deploy and disarm normally, but the detector may have stopped working or been lost. In addition, the wireless signal strength between the detector and the host of Guangzhou Junkai Electronic Technology Co., Ltd. is not guaranteed. The signal is sometimes there and sometimes not. The alarm test is normal during installation, but the signal weakens or even disappears completely after a period of use. Obviously, the danger of using such a system is self-evident.
　　
　　For example, the wireless products of Israel's VISONIC company, each detector has signals such as low battery voltage, anti-dismantling, and periodic self-test, and the host also has corresponding identification and processing functions, which can detect low voltage, anti-dismantling, interference and blocking in time and issue warning information; at the same time, each host has a wireless signal strength test function, and the installer can immediately know the signal strength between a detector (including multi-level repeaters) and the host, and adjust the installation position or consider adding one or more wireless signal relay devices.
　　
　　In view of the unstable factors of transmission signals, Junkai Electronics believes that the problem of signal interference can be avoided, because a set of automatic detection functions can be added to the alarm host. Whenever similar problems occur during signal transmission, the host's automatic detection device will react and alarm, especially for malicious interference damage, the host's reaction is more intense, that is, this system has good anti-interference and anti-malicious damage functions. In addition to this function, the EL host it represents also has a digital display bar that specifically indicates the strength of the transmission signal. This is similar to the signal strength display of a mobile phone, except that the mobile phone uses a few grids to indicate it, while they are indicated by numbers. False
　　
　　alarm and missed alarm problems
　　
　　It is understood that false alarms and missed alarms have always been a problem that plagues the entire wireless alarm system. Even the best products cannot achieve an alarm accuracy rate of 100%. Therefore, under the premise that false alarms and missed alarms are inevitable, how to find a set of effective measures to reduce the probability of their occurrence has become the focus of people's special attention.
　　
　　1. False alarm False
　　
　　alarms occur frequently in wireless alarm systems. This is due to the influence of factors such as operation, environment, and product quality, making the occurrence of false alarms unavoidable.
　　
　　First, incorrect operation: The lack of humanization of the product is the main reason for incorrect operation. First, wireless products use remote controls to arm and disarm, and users often forget to bring the remote control in real life; second, the host operation is complicated, such as various programming, requiring users to make too many self-selected settings, etc., which is very easy to operate incorrectly.
　　
　　Second, environmental factors: Because the core component of passive infrared (whether it is a single, dual or quadruple) detectors is a pyroelectric detector, its essence is only to work on changing signals, such as detecting a moving human body to generate an alarm. In this way, if there is a change in local temperature, such as the fluttering of curtains, the flow of large indoor and outdoor airflow, etc., it will cause false alarms. Therefore, the choice of its installation point is very important, and it must be avoided in places where the temperature is easy to change.
　　
　　In addition, since some detectors are pet-proof and anti-false alarm by reducing sensitivity, but too low sensitivity will cause missed alarms, so pay attention to the balance and compromise in choosing adjustments. Guangzhou Junkai Electronic Technology Co., Ltd. believes that in the actual installation of wireless alarm system projects, it is possible to adapt to local conditions according to the surrounding environment and equipment. When installing the host, the location consideration is very important. It should not be too obstructive during installation, but it should not be blocked by objects. It is best to place it in the center of the room. At the same time, it is also necessary to consider placing the detector at a certain height to prevent pets from touching it.
　　
　　Third, product quality: There are three factors: design, manufacturing process, and component quality. The defects in the design itself are irreparable (but the design can be perfect in terms of "stability"). The manufacturing process can reduce defective products by strengthening management, and the quality of components can also be controlled through quality control procedures and means to reduce defective products. In response to this problem, Zhejiang Haining Haishen Electronics Co., Ltd. has a set of systematic product testing procedures to deal with it. Its manager Yu Peihua introduced: "Each of our products must undergo three very systematic testing procedures before leaving the factory, including semi-finished product substrate debugging and testing, whole machine debugging and testing, and packaging and warehousing overall testing. Strict tracking is carried out before the product leaves the factory, thereby ensuring the quality of the products on the market."
　　
　　2. Missed reports
　　
　　Misreporting is another specific manifestation of product instability and reliability. The main reasons for missed reports are improper operation, product quality and weak battery. The solutions to operation and product quality problems are basically similar to those to false reports, but the most critical factor here is the weak battery problem.
　　
　　Although the battery problem is a major concern for manufacturers and users, through understanding, each manufacturer still has its own countermeasures for this. The specific solutions are as follows: First, by setting up a set of automatic warning devices for weak battery and undervoltage inside the host, when encountering weak battery or undervoltage, the host will automatically send out a signal prompt tone to inform the user after detecting it, and the product can continue to be used for a long time after the host sends out the prompt alarm, which is conducive to the user having enough time to replace the battery; second, develop new circuit designs as much as possible, or use low-energy components and products to achieve low power consumption of the product; Regarding their product to solve this problem, they said: "In terms of product technology, the development of detector products that can automatically sleep and standby can solve the problem of insufficient battery voltage well. When not in use, it will automatically switch to standby or sleep mode, which can reduce the power consumption of the battery and thus extend the service life of the battery voltage." Third, it is powered by high-energy lithium batteries. The service life of some high-energy batteries is generally about three years, and some products can reach five years. This provides a strong guarantee for the normal operation of the product's alarm work.  Manufacturers such as BOSCH, Israel EL, Israel Visonic, GE Security, etc. have solved the battery problem well, thereby reducing the incidence of missed reports.
　　
　　Security issues of codecs
　　
　　Since wireless alarm system products use codec transmission, there are occasional problems of low security and easy destruction of codes during deployment and disarming. The security of the code is an important performance indicator for detecting wireless alarm systems. Once the codec of the alarm system is stolen and cracked, it will seriously damage the operation of the entire alarm system. For this reason, engineers and end users have put forward higher requirements for manufacturers. Therefore, many manufacturers have developed a set of corresponding encryption technologies to solve the problem. Guangzhou Junkai Electronic Technology Co., Ltd. only needs to increase the codec group code or the number of groups, which can greatly enhance the complexity of the code and make it more difficult to crack.
　　
　　"We have designed a unique rolling code encryption technology on the host, which can form a total of 4 billion sets of digital codes; if others test it, the system will automatically jump to another code, and the encryption system is very well done. Therefore, even if someone maliciously damages it, it is difficult to achieve the goal." Yu Gang of Huaji introduced this. In addition, GE's wireless alarm products also have their own unique solution to the problem of signal interference. According to  Minni  Lin of GE Security, GE has increased the built-in chip code from the original 58 bits to 80 bits in the design of the product, so that even if others deliberately interfere, they cannot immediately see through the design program of the 80-bit code, thereby greatly improving the ability of the code to be cracked.
　　
　　In short, the technologies of manufacturers are varied and diverse, but they all have the same goal, that is, they hope to present the best products to consumers. In fact, when dealing with these problems, all manufacturers use "developing new technologies as the main means to improve product defects", which is very popular with users.