Alarm sensors for housing: details and principle of operation
Over the decade, more and more users choose to protect their homes and the safety of those who live there with security systems. In this context, alarm sensors are the main components of a good security alarm for the home, so their correct installation in places of approaches to the house, for example along balconies or in gardens, is very important.
The most common alarm sensors are PIR (passive infrared) sensors, which use infrared technology. These devices are small and easy to use; they are able to detect movement in the area they monitor and, as soon as it is detected, activate the alarm. Their mechanism of action is based on the fact that any object or body emits heat, which can be detected by a pyroelectric sensor, so it is always better to install these devices away from heat sources such as radiators, fireplaces, stoves, etc. If pets move freely around the house or in the yard, the infrared sensors may work by mistake; for this reason, in the presence of pets, it is recommended to buy special sensors with immunity to pets: such devices are calibrated with the required sensitivity and allow you to distinguish the volume of an animal from the volume of a person.
Also, widely used are dual-technology alarm sensors that simultaneously use infrared and electromagnetic technology (PIR + MW). With dual technology sensors, the alarm is activated only when both types of technology detect changes in the monitored area. Thus, combined sensors use two technologies that interact with each other, namely infrared rays and microwaves: in this way, not only does the level of security alarm reliability increase to determine the presence of outsiders in the area of operation, for monitoring, but in this case there is also a double control compared with a conventional PIR sensor that sends an alarm signal only when the infrared sensor is activated.
The choice between PIR sensors and sensors with dual technology should be made primarily on the basis of how effectively they are separated or combined. Obviously, the operating conditions should be evaluated separately when choosing between the two options, since both have their own strengths: therefore, the task of the installation engineer will be to analyze the environment and the individual needs of the owner in order to choose the best device.