New generations of alarms allow owners to count on a high degree of security function with minimal equipment. Compactness and accuracy in performing 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 communication 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 almost impossible to enter an apartment or house without detection.
Motion sensor device
The device has a small size, which allows it to be installed in secluded places. As a rule, sensors of this type work on the basis of infrared radiation, so an appropriate receiver and signal processing circuit is installed in the center. A typical security motion detector is usually equipped with a pyroelectric infrared element and a lens that focuses the light and also registers the incoming signal. It is important to note thatthe number of small lenses used depends on the sensitivity of the sensor, respectively, and the quality of its work.
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 grippy coatings for such sides, which facilitates installation.
Operation principle
Motion sensors are often confused with presence detectors. The difference between them is just the principle of operation. If the first device focuses rather 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 work with presence detectors. In both cases, the devices register the appearance or disappearance of infrared radiation in the observation area.
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 a person. This is a significant advantage over alternative detector options, as the risk of erroneous operation of the device due to household appliances is minimized. However, today you can also find motion sensors for alarms on the market, the operation of whichbased on thermal susceptibility. But such devices can rather 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 sensor masking. 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 provides advantages, but on the other hand, there is a problem of power supply. In the modern assortment, you can find a battery-powered motion sensor that can work for weeks and even months without updating the batteries. For a small apartment, this is a good indicator, but if you plan to provide an alarm system for a house with a dozen of such devices, then regular replacement of batteries can greatly burden the wallet.
Key Features
One of the main performance characteristics is the perception angle, which can vary from 180° to 360°. If a burglar alarm with a motion sensor is planned for a certain entrance area, then you can limit yourself to the 180 ° option. With proper installation and correct calculation of the view, 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 measure of sensor performance 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 susceptibility that wireless motion sensors should have, designed for installation in a particular room.
Types of wireless motion sensors
There are several signs by which manufacturers classify such devices. Basically, they start from the principles of work. For example, there are passive and active models. The former involve the processing of signals coming from objects located in the observation area. According to this principle, a burglar alarm works with a motion sensor that receives infrared radiation. However, there are also devices that analyze changes in their own signals supplied to the environment. These are active sensors, which include ultrasonic devices. They constantly emit noise waves and at the moment of their deviation from the norm, they detect the detection of an outsider.
How to connect a motion sensor?
Installation of the device is carried out by simple operations with the 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. Usually questions about howconnect a motion sensor, solved by performing two steps. First of all, it is necessary to carry out some kind of activation of the detector. To do this, you need to connect the jumpers of the sensor and the main alarm unit for a couple of seconds. The second step involves setting the appropriate radio frequency between the devices on which they will interact.
Question of price
In the simplest modifications, such devices can cost about 500-700 rubles. These are compact devices with a short range and rather 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 receive a high-quality assembled model not from a Chinese manufacturer, but from a supplier of branded European equipment. In this case, it is also not necessary to count on technical and operational refinements, but stability and reliability will be ensured.
The most effective acquisition can 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
With all the effectiveness of motion sensors, they do not always guarantee high accuracy when fixing a signal. The big problem in themwork still remains a considerable percentage of false positives. Nevertheless, in combination with other types of detectors, wireless motion sensors become a fairly effective tool for detecting unauthorized intrusion. But it is important not to forget that the accuracy of detecting an intruder does not ensure the protection of 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 the discovery of the fact of penetration.
