New generations of alarms allow owners to count on a high degree of security function with minimal equipment size. Compactness and accuracy of tasks are the main differences between modern equipment of this type. Such characteristics are achieved in various ways, the most developed of which involve the use of wireless technologies. Also, manufacturers are increasingly relying on motion sensors for signaling as an effective means of fixing unwanted objects in a protected area. In a single complex with a control panel, a set of such sensors makes it virtually impossible to penetrate an apartment or house without detection.
Motion sensor device
The device is small in size, which allows it to be installed in secluded places. Typically, sensors of this type operate on the basis of infrared radiation; therefore, an appropriate receiver and a signal processing circuit are installed in the center. A typical security motion sensor is usually equipped with a pyroelectric infrared element and a lens that focuses the light and also records the incoming signal. It is important to note that the sensitivity of the sensor, respectively, and the quality of its work depends on the number of small lenses used.
As for the body, it can be divided into two parts - movable and fixed. Depending on the modification, the movable side can have several levels of freedom and rotate in different planes. The fixed part allows you to securely mount motion sensors for signaling to different surfaces. Manufacturers in some models of detectors provide special tenacious coatings for such sides, which facilitates installation.
Operating principle
Motion sensors are often confused with presence detectors. The difference between them lies precisely in the principle of work. If the first device focuses more on expanding the detection radius, then presence sensors specialize in processing signals about the visual fixation of the position of the human body. However, in practice, motion sensors for signaling provide approximately the same nature of operation with occupancy detectors. In both cases, the devices detect the appearance or disappearance of infrared radiation in the observation zone.
It is important to note that the initiator of the signals is not heat, but a change in the characteristics of the light on the photocells due to the movement of the person. This is a serious advantage over alternative detector options, since the risk of device malfunctions due to household appliances is minimized. However, today you can find motion sensors for signaling on the market, whose operation is based on thermal susceptibility. But such devices can most likely be attributed to the mentioned presence detectors.
Features of wireless models
The main difference between wireless models is that there is no need to connect via cable. This eliminates unnecessary work during the installation process, saves money, and also enhances the masking of the sensor. Instead of a wired connection, radio modules or network channels are usually used. On the one hand, this principle of interaction with the control panel gives advantages, but on the other, there is a problem of energy supply. In the modern assortment, you can find a battery-powered motion sensor that can work for weeks or even months without updating the batteries. For a small apartment, this is a good indicator, but if it is planned to provide an alarm system at home with a dozen such devices, then regular replacement of the batteries can pretty much burden the wallet.
Main characteristics
One of the main performance characteristics is the angle of perception, which can vary from 180 ° to 360 °. If you plan a burglar alarm with a motion sensor for a specific entrance zone, then you can limit yourself to a 180 ° option. With proper installation and proper calculation of the review, this angle is quite enough to fix movements in the doorway. Models with full visibility in a circle are preferable to use for tracking indoors. Such models are usually installed on the ceiling.
The next indicator of the effectiveness of the sensor is sensitivity. To determine the optimal value of this parameter, specialists use a formula with the ratio of the active and passive sections. The intensity of the alternation of such zones determines the level of light sensitivity that wireless motion sensors should have at their disposal, designed for installation in a particular room.
Types of Wireless Motion Sensors
There are several indications by which manufacturers classify such devices. Basically, they are based on the principles of work. For example, there are passive and active models. The first involves processing signals from objects located in the observation zone. By this principle, a burglar alarm with a motion sensor that receives infrared radiation works . However, there are devices that analyze changes in the intrinsic signals fed into the environment. These are active sensors, which include ultrasonic devices. They constantly emit noise waves and at the time of their deviation from the norm, they detect the detection of an unauthorized person.
How to connect a motion sensor?
Installation of the device is carried out by simple operations with fasteners that come with the kit. The main work on preparing the device involves connecting and configuring. Depending on the method of providing wireless communication, one or another connection scheme is implemented. Typically, questions about how to connect a motion sensor are resolved by performing two actions. First of all, it is necessary to carry out a kind of detector activation. To do this, connect the jumpers of the sensor and the main alarm unit for a couple of seconds. The second step involves installing between the devices the appropriate radio frequency at which they will interact.
Price issue
In the simplest versions, such devices can cost about 500-700 rubles. These are compact devices with a short range and fairly limited sensitivity parameters. In the middle category you can find a functional motion sensor, the price of which will be about 1000 rubles. For this amount, the user can get a well-assembled model not from a Chinese manufacturer, but from a supplier of branded European equipment. In this case, too, it is not necessary to count on technical and operational refinements, but stability of work and reliability will be ensured.
The most effective acquisition may be a multifunctional infrared motion sensor. The price of such models often exceeds 2000 rubles, but for this money the device will provide the ability to work in several modes. For example, in addition to light radiation, such detectors also provide signal registration based on thermal susceptibility.
Conclusion
For all the effectiveness of motion sensors, they do not always guarantee high accuracy when capturing a signal. A large problem in their work is still a considerable percentage of false positives. Nevertheless, in combination with detectors of another type, wireless motion sensors are becoming a rather effective tool for detecting unauthorized entry. But it is important not to forget that the accuracy of the detection of the attacker does not protect the property, but only allows the owner to learn about the threat in a timely manner. Therefore, it is important to calculate the further actions of the system after detecting the fact of penetration.