CN105488936A - Perimeter intrusion detection and alarm device - Google Patents

Abstract

The invention discloses a perimeter intrusion detection and alarm device, comprising a magnetic field radiation source composed of a high-frequency current source connected to a cable I; and a magnetic field detector composed of a detection trigger alarm device connected to a cable II, the detection trigger alarm device connected to There are alarms. This peripheral intrusion detection and alarm device has simple structure, convenient installation, low cost, high stability, sensitive detection, low false alarm rate, concealed layout, and realizes all-weather work.

Description

A perimeter intrusion detection and alarm device

technical field

The invention relates to a detection device, in particular to a perimeter intrusion detection and alarm device.

Background technique

In some important security areas, in order to prevent illegal intrusion and various sabotage activities, the traditional preventive measures are to set some (such as iron fences, walls, wire fence nets, etc.) barriers or barriers at the outer perimeter of these areas, arrange Personnel stepped up patrols. In the current situation where criminals use advanced science and technology, and criminal methods become more complex and intelligent, traditional prevention methods are difficult to meet the needs of key departments and key unit security work. Manpower prevention is often affected by factors such as time, region, personnel quality and energy, and loopholes and mistakes are inevitable.

With the development of society and the progress of science and technology, the perimeter intrusion detection and alarm device has become an important part of the security system and the first line of defense of the security alarm system. The intrusion alarm system has received more and more attention from all aspects, and the needs of users are urgent. However, the existing perimeter intrusion detection and alarm devices cannot be widely used due to high technical difficulty, large investment, general security effect, and difficulty in meeting social needs.

Contents of the invention

Aiming at the problems existing in the above-mentioned prior art, the present invention provides a perimeter intrusion detection and alarm device with simple structure, convenient installation, low cost, high stability, sensitive detection, low false alarm rate, concealed layout, and all-weather work.

In order to achieve the above purpose, this perimeter intrusion detection and alarm device includes a magnetic field radiation source composed of a high-frequency current source connected to the cable I;

And a magnetic field detector composed of a connecting cable II of the detection trigger alarm device, the detection trigger alarm device is connected with an alarm.

Further, the cables I and II are respectively arranged side by side under the ground of the detection area along the perimeter of the detection area.

Further, the detection trigger alarm device includes a current transformer T1 connected to the cable II, and the current transformer T1 is connected with a high-frequency Schottky diode D1, a resistor R1, a resistor R2 and a capacitor C1.

Compared with the existing technology, this peripheral intrusion detection and alarm device is composed of a high-frequency current source, a detection trigger alarm device and two sets of cables, with simple structure, convenient installation, low cost, high stability, sensitive detection and low false alarm rate , the layout is concealed, and it can work around the clock.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a detection trigger alarm circuit diagram in the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1 and Figure 2, this perimeter intrusion detection and alarm device includes a magnetic field radiation source composed of a high-frequency current source connected to the cable I;

And a magnetic field detector composed of a connecting cable II of the detection trigger alarm device, the detection trigger alarm device is connected with an alarm.

The AA' loop formed in the cable I constitutes a magnetic field radiation source, which is connected to a high-frequency current source. Because the magnitude and direction of the current change periodically, the electromagnetic field generated by the current changes periodically, so that in the AA of the cable I 'A periodic alternating magnetic field is generated around the loop. The BB' loop formed in the cable II is in the periodically changing alternating magnetic field generated by the AA' loop, which will generate a periodic induced current.

Using the space discrimination theory, for the magnetic noise source far away, the magnetic field at the detection coil of the BB' loop is a uniform magnetic field, and the magnetic flux passing through the two pairs of coils is equal in size and opposite in direction and cancels each other out, so the geomagnetic field and Interference of the environmental magnetic field; for a magnetic field source that is relatively close, because the spatial magnetic field distribution of the two pairs of coils is uneven, the BB' loop detection coil can detect the signal.

When there is biological invasion in the area between the AA' loop and BB' loop, the magnetic permeability of the magnetic field medium in this space will change, and the alternating magnetic field distribution around the AA' loop will be distorted due to mutual superposition, and BB' The average value of the amplitude of the induced current in the loop also changes within one cycle, and after being detected by the detection trigger alarm device, when the average value exceeds the set value, the alarm is triggered.

Further, the cables I and II are respectively arranged side by side under the ground of the detection area along the perimeter of the detection area.

Further, the detection trigger alarm device includes a current transformer T1 connected to the cable II, and the current transformer T1 is connected with a high-frequency Schottky diode D1, a resistor R1, a resistor R2 and a capacitor C1. The induced current in the BB' loop formed by the cable II is coupled by the current transformer T1, rectified by the high-frequency Schottky diode D1, integrated and low-pass filtered by the resistor R1, resistor R2 and capacitor C1, and finally detects the average value of the induced current amplitude When the amount of change exceeds the set value, the alarm will be triggered to complete the alarm.

To sum up, this peripheral intrusion detection and alarm device has simple structure, convenient installation, low cost, high stability, sensitive detection, low false alarm rate, concealed layout, and can work around the clock.

Claims (3)

1. A perimeter intrusion detection and alarm device, characterized in that, Including a magnetic field radiation source composed of a high-frequency current source connected to the cable I; And a magnetic field detector composed of a connecting cable II of the detection trigger alarm device, the detection trigger alarm device is connected with an alarm. 2. A perimeter intrusion detection and alarm device according to claim 1, characterized in that: The cables I and II are respectively arranged along the perimeter of the detection area and arranged side by side under the ground of the detection area. 3. A perimeter intrusion detection and alarm device according to claim 1, characterized in that: The detection trigger alarm device includes a current transformer T1 connected to the cable II, and the current transformer T1 is connected with a high-frequency Schottky diode D1, resistors R1, R2 and capacitor C1.