How Window/Door Sensor Works?

Publish Time: 2020-10-15     Origin: Site

Window/Door Sensor is usually composed of a wireless transmitter module and a magnetic block. There is a "reed switch" at the two arrows of the wireless transmitter module. When the distance between the magnet and the reed switch is within 1.5cm, the reed switch is disconnected. Once the distance between the magnet and the reed switch exceeds 1.5cm, the reed switch will be closed, causing short circuit and then send an alarm signal to the host, the alarm light will be on at the same time.



Door Sensor's wireless alarm signal can transmit 200 meters in open space and 20 meters in general residence, which is closely related to the surrounding environment. It generally uses a power-saving design. It does not emit radio signals when the door is closed, which consumes only a few microamps of power. When the door is opened, it immediately sends a wireless alarm signal of about one second, and then stops by itself, even if the door keeps open, it will not emit any more signals.


The Window/Door Sensor is usually mounted above the inside of the door. It consists of two parts: the small part is a permanent magnet, and there is a magnet inside to generate a constant magnetic field. The larger part is the Door Sensor body, which has a normally open reed switch inside. When the permanent magnet and the reed switch are close together (less than 5mm), the Door Sensor is on standby.



When the permanent magnet leaves the reed switch for a certain distance, the Door Sensor immediately transmits a high frequency radio signal that contains an address code and its own identification code (i.e. a data code). The RF receiver identifies the address code of this radio signal to determine if it is the same alarm system, and then determines which door is alarm.


The smart home system of the Internet of Things consists of home environment perception interaction layer, network transmission layer and application service layer. The Home Environment Perception Interactive Layer is composed of sensor nodes with wired or wireless functions. It mainly implements the collection of home environment information, the acquisition of owner status and the entry of visitor identity characteristics. The Network Transport Layer is mainly responsible for the transmission of home information and director control information. The Application Service Layer is responsible for the control of home facilities or application service interfaces.


As a member of the smart home system, Window/Door Sensor has compact size and relatively low technical requirement, which is the entry point for our ordinary families to enter the smart home field. Door Sensor belongs to the home environment perception interaction layer. There are two ways for ordinary gangsters to enter a house from the door: one is to steal the master's key and open the door; the other is to pry the door. No matter how the gangster enters, he must open the door of the house.




Once the burglar opens the door, the door and the door frame will shift, the door sensor and magnet will also shift, the radio signal will be sent to the host immediately, the host will ring the alarm and dial preset phone numbers, or send messages via APP. 


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