1. Active infrared detector: It consists of an infrared transmitter and an infrared receiver. An infrared emitter emits one or more modulated infrared rays to an infrared receiver. When there is no obstacle between the transmitter and receiver, the detector will not give an alarm. When there is an object blocking, the output signal of the receiver changes and the detector gives an alarm.
2. Passive infrared detector: There are two key components, one is Fresnel lens and the other is pyroelectric sensor. Anything in nature that is higher than the absolute temperature (-273o) will produce infrared radiation, and the infrared energy wavelength released by objects with different temperatures is also different. The body temperature is constant, which is different from the ambient temperature. When the human body moves, this difference is detected by the thermoelectric sensor through the Fresnel lens, thus outputting an alarm signal.
3. Microwave detector: applying the principle of Doppler effect. In the microwave section, when transmitting at a frequency, when the transmitted microwave meets a fixed object, the reflected microwave frequency remains unchanged, that is, F transmission =f reception, and the detector will not send out an alarm signal. When the emitted microwave meets a moving object, the frequency of the reflected microwave will change, that is, F will send out ≠f to receive, and the microwave detector will send out an alarm signal.
4. Vibration detector: The vibration detector is based on detecting the vibration signals generated when intruders engage in various destructive activities. For example, when intruders engage in destructive activities such as digging walls, digging holes, destroying ATMs and breaking open safes, these objects will vibrate. Detectors that use these vibration signals to trigger alarms are called vibration detectors.
5. Binary infrared detector and quaternary infrared detector: A detector with two detection sources integrates two pyroelectric sensors with the same performance but opposite polarity. This detector is a binary detector. The detector with four detectors integrates four pyroelectric sensors with the same performance but opposite polarity, which is a four-value detector.
6. Double detectors: In order to overcome the shortcomings of detectors with single technology, two detectors with different technical principles are usually integrated, and the detector that gives an alarm only when the sensors of both detection technologies detect human motion is called a double detector. Microwave+passive infrared is a common dual detector in the market.
7. Three-Sword Detector and Four-Sword Detector: The Three-Sword Detector is just a gimmick promoted by some domestic manufacturers, using microprocessor technology as detection means. In fact, this can only be regarded as a three-technology detector. If these are all three lessons, can infrared microwave microprocessing prevent pets from hiding and disguising be called a six-lesson detector? The real three-mirror detector must have three detection technologies: passive infrared+microwave+ultrasonic detector.
What does a household alarm do?
1. Anti-robbery Purpose: Once someone is robbed at home, we can use the alarm host to send an alarm signal to the outside world and use external forces to deal with these problems.
2. Help-seeking purpose: This family alarm is set to contact relatives in advance, so that the elderly or children at home can be informed and ask for help in time when something happens.
3. Remote monitoring purpose: We can hear indoor scenes in time by using the alarm telephone, and we can also receive pictures by receiving multimedia messages, which are very favorable evidence.
4. Prevention of flammable gas poisoning Purpose: For some omni-directional home alarm systems, some information about gas leakage such as gas or liquefied petroleum gas can be detected, and then corresponding measures can be taken to remedy it in time.
5. Anti-theft purpose: This is an essential function for us to install this household alarm. When an illegal person enters the house, the corresponding burglar alarm will inform the owner through some telephones or even multimedia messages, so that the owner can make a choice or take countermeasures according to the alarm content to avoid greater losses.
6. Fire prevention purpose: use smoke detector to detect smoke concentration, and once a fire is found, the owner will be informed by fire alarm.
Matters needing attention in purchasing household alarm
Home intelligent burglar alarm can be divided into wired and wireless. Wired alarm has the characteristics of stable communication, strong anti-interference ability and low investment, and is very suitable for newly built buildings with reserved connecting wires in the walls. However, its deficiency is mainly that it is not flexible enough to meet the changing needs of users, which is a very troublesome thing for those who have installed it.
Wireless can avoid the above-mentioned similar situations. It has the characteristics of flexibility and simplicity, and its main disadvantages are its vulnerability to external interference and relatively high investment.
We can choose wired or wireless home alarm according to our needs.
Home intelligent burglar alarm can also be purchased from two functions: on-site alarm and self-help telephone alarm.
On-site alarm means that when theft occurs, the probe transmits the detected signal to the host computer, and the host computer sends out an audio alarm sound, which has a certain deterrent effect on thieves. Automatic telephone alarm not only has the function of on-site alarm, but also can automatically dial the number we set, and can also inform the specific location of the alarm in detail. Using this function, we can form an alarm LAN center with the community security alarm center. When we choose, we consider the on-site treatment part and the follow-up treatment part according to our family size, family building method, surrounding specific conditions and family members.
With the continuous development of semiconductor electronic components, at this stage, people's home intelligent anti-theft alarm has greatly improved in technology and product quality, while the price has also dropped significantly. At present, the price is around 1000 yuan, which brings great convenience to ordinary families to use the home burglar alarm.