When choosing a home alarm system, there are a number of factors that you must consider before making a final purchase. Maybe at the top of your list of considerations is the type of alarm. However, you also have to decide what type of sensor you want to install. Sensors are the most important component of your home alarm system. This will detect intrusions on your property. The following is a list of the most common sensors on the market.
Infrared Passive Motion Detector
The PIR sensor is one of the most common detectors used in home alarm systems because of its affordability and practicality. The term passive refers to the fact that these sensors function without the need to generate and emit their own energy. The types of home alarm systems are able to detect body heat, or more precisely changes in ambient temperature. If the PIR detects a temperature surge caused by the presence of a foreign object or intruder, it will be turned off. However, an alarm is usually set at a delay, allowing the sensor to distinguish between temperature zones to determine if there is actually an intruder. This delay also allows the homeowner to deactivate the alarm if there is a false positive. Because infrared energy does not penetrate the glass, passers-by cannot accidentally trigger an alarm.
These sensors utilize high frequency sound waves to detect motion in a limited area. Unheard frequencies in the human ear, between 25 kHz and 75 kHz, are transmitted and reflected from walls, furniture and ceilings in a protected space. Using the Doppler shift principle, the sensor can detect motion as a result of a stable frequency shift; Moving objects entering the protected space change the frequency of the surrounding sound waves. This shift triggers a home alarm system.
This function is similar to an ultrasonic detector, but instead of using sound waves, they use high frequency radio waves. It can penetrate walls, unlike ultrasonic waves.
This is generally used to protect windows and doors. They are a popular choice because of their affordable price, durability and ease of use. Homeowners can easily install it themselves; they consist of two separate parts, magnets and switches. Swich contains a spring that when closed, creates an electric circuit with a magnet. If the door or window is opened, a circuit breakdown will occur, triggering an alarm.
Glass Break Detectors
The sound of glass breaking occurs in a wide frequency band – from infrasonic that cannot be heard by humans, to ultrasonic, which can indeed be heard by humans. The broken glass detector is installed next to the glass panel and turned off when the glass breaks.
This detects the presence of intruders using infrared light, which is usually stacked in rows of two or more. If someone blocks the beam, the home alarm system will die.
This device is mounted on a kind of barrier, such as a fence, and detects vibration. The sensor can be adjusted to feel different vibration levels, which is very useful to avoid false alarms caused by animals or wind disturbances.