Infrared sensors for the protection of the home territory
Let’s deal with the technologies that are used in the work of security sensors of security systems — infrared and microwave.
Infrared sensors are quite a sensitive issue, as this new technology lacks reliability and the fact that the ratio between quality and price is not the best. You are certainly not wrong when you say that infrared protection does not guarantee 100% safety, but it is also true. The infrared type of technology for security devices has been quite popular for a decade now due to the low cost and good performance provided to users.
The principle of operation of a magnetic sensor is based on a change in the frequency of a radio signal reflected from a moving object. This (Doppler effect) is widely used in radar systems for remote speed measurement. A moving object causes an electrical signal to appear at the output of the microwave transceiver module. Since the signal level depends on the reflection properties of the object, motion sensors can be used to signal a chain (tape) break, the presence of any objects or materials on the conveyor belt. The tape has a smooth surface and a low reflection coefficient.

Sensors that use dual technology are also extremely reliable elements, less reliable than conventional infrared, but they are almost perfectly protected from false triggering of security systems.
In any case, the best property protection with alarm system sensors is multi-layered protection: that is, the use of several technologies (to get the most from each), for example, external perimeter protection, magnetic opening contacts for monitoring entrance and internal doors and windows, internal capacitive sensors and other security devices; thus the forces in the field and the information the owner can obtain in case of alarm will be greater.
When planning the use of a security alarm system in a house or other types of buildings, it is important to remember that technology is not enough to make a product good and reliable, as other important factors must also be taken into account, such as your own security needs, ease of installation and correctness of its performance, reliability and the relationship between the quality of the materials used to make the various components and the final price for the customer.