How the door magnetic sensor works

Everyone knows that there are many products and types of smart home systems. As the star products such as routers and switch panels are attracting attention from the market, they seem to have forgotten the door magnetic system that is also important in intelligent systems. Then, what is the working principle of the door magnetic sensor?

What is the working principle of the door magnetic sensor: wired door magnetic sensor

In the smart home access control system, the function of the magnetic switch is responsible for the magnetic power of the door, the magnetic field is energized (closed door), the power is demagnetized (opening the door), the magnetic door is installed on the door and the door cover, and the switch is installed in the house, with automatic Used by the door closer, it can generally withstand a pulling force of 150 kg.

The wired door magnet is more concealed for the embedded installation. It is understood that the opening of the induction door and window is suitable for the wired normally closed/normally open switch signal of the wooden or aluminum alloy door and window. Door magnets are used to detect whether doors, windows, drawers, etc. are illegally opened or moved. It consists of a wireless transmitter and a magnetic block. The door magnetic system is actually the same as the bed magnet. Here is mainly the case of gate magnetism.

What is the working principle of the door magnetic sensor: wireless door magnetic sensor

The wireless door magnet is composed of a wireless transmitting module and a magnetic block. The wireless transmitting module has a “steel reed” component at two arrows, when the distance between the magnet and the reed pipe is kept within 1.5 cm. The steel spring tube is in the off state. Once the distance between the magnet and the steel spring tube exceeds 1.5 cm, the steel spring tube will close, causing a short circuit, and the alarm indicator light is on, and an alarm signal is sent to the host.

The wireless door alarm wireless alarm signal can transmit 200 meters in the open space and 20 meters in the general house, which is closely related to the surrounding environment. The wireless door magnet generally adopts a power-saving design. When the door is closed, it does not transmit a radio signal. At this time, the power consumption is only a few micro-amps. When the door is opened, the wireless alarm signal is immediately transmitted for about 1 second, and then stops by itself. At this time, even if the door is always open, no signal will be transmitted.

The wireless door magnet is also designed with a battery low voltage detection circuit. When the voltage of the battery is lower than 8 volts, the lower LP LED will be lit. In this case, the A23 alarm battery must be replaced immediately, otherwise the reliability of the alarm will be affected. .

The wireless door sensor is generally mounted on the inside of the door. It consists of two parts: the smaller part is a permanent magnet, the inside has a permanent magnet to generate a constant magnetic field, and the larger is the wireless door magnet body. There is a normally open reed switch. When the permanent magnet and the reed switch are close together (less than 5 mm), the wireless magnetic sensor is in the working state.

When the permanent magnet leaves the reed switch for a certain distance, the wireless door magnetic sensor immediately transmits a high-frequency radio signal of 315 MHz including the address code and its own identification code (that is, the data code). The receiving board recognizes the address code of the radio signal. Determine whether it is the same alarm system, and then determine which wireless door magnetic alarm is based on its own identification code (that is, the data code).