CN112329079A

CN112329079A - Anti-dismantling circuit

Info

Publication number: CN112329079A
Application number: CN202011210424.2A
Authority: CN
Inventors: 董庆军
Original assignee: Confidential Transportation Bureau Of General Office Of Cpc Central Committee
Current assignee: Confidential Transportation Bureau Of General Office Of Cpc Central Committee
Priority date: 2020-11-03
Filing date: 2020-11-03
Publication date: 2021-02-05

Abstract

The invention relates to a disassembly prevention circuit which comprises a first power supply, a second power supply, a detection switch, an alarm and an alarm switch, wherein one end of the detection switch is connected with one end of the first power supply, the other end of the detection switch is connected with the control end of the alarm switch, and the alarm is connected with the alarm switch in series and then is connected in a power supply loop of the second power supply; the detection switch is connected with the alarm switch when the shell is forcibly opened, and the alarm gives an alarm in response to the connection of the second power supply circuit. The invention alarms when the shell of the device to be protected is illegally opened, thereby protecting the device.

Description

Anti-dismantling circuit

Technical Field

The invention relates to the field of electronic circuits, in particular to an anti-dismantling circuit.

Background

With the rapid development of social economy, information technologies such as the internet and computers rise and infiltrate into the aspects of society. Among them, many electronic products and control devices do not allow unauthorized operations by unrelated persons for safety reasons, and particularly do not allow the housings of the devices and products to be opened.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides an anti-dismantling circuit which is applied to an electronic product or control equipment to prevent the product or the equipment from being illegally dismantled.

In order to solve the technical problem, according to one aspect of the present invention, the present invention provides a tamper circuit, which is installed in a housing of a device to be protected, and includes a first power supply, a second power supply, a detection switch, an alarm and an alarm switch, wherein one end of the detection switch is connected to one end of the first power supply, the other end of the detection switch is connected to a control end of the alarm switch, and the alarm is connected in series with the alarm switch and then connected in a power supply loop of the second power supply; the detection switch is connected with the alarm switch when the shell is forcibly opened, and the alarm gives an alarm in response to the connection of the second power supply circuit.

According to another aspect of the invention, the invention provides a tamper circuit, which is installed in a housing of a device to be protected, and comprises a first power supply, a second power supply, a normally-open detection switch, an alarm and a first triode, wherein a first end of the detection switch is connected to a first power supply end of the first power supply, and a second end of the detection switch is connected to a base electrode of the first triode through a base electrode resistor; a collector electrode of the first triode is connected with a first end of the alarm, and an emitter electrode of the first triode is connected with a second power supply end of the first power supply; the second end of the alarm is connected with the power supply end of the second power supply; when the shell is opened forcibly, the detection switch is closed, and the alarm gives an alarm.

The anti-disassembly circuit provided by the invention can give an alarm when the device to be protected is operated illegally, and further can stop the device to be protected, so that the safety of data transmission of the device to be protected is ensured.

Drawings

Preferred embodiments of the present invention will now be described in further detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a tamper resistant circuit according to one embodiment of the present invention;

FIG. 2 is a schematic external view of an apparatus employing tamper-evident circuitry in accordance with one embodiment of the present invention;

FIG. 3 is a schematic diagram of a detection switch in accordance with one embodiment of the present invention;

FIG. 4 is a schematic diagram of the positional relationship of the device housing to be protected and the Hall switch according to one embodiment of the present invention;

FIG. 5 is a schematic view of a housing seal arrangement of a device to be protected according to one embodiment of the present invention;

FIG. 6 is a schematic diagram of a detection switch circuit according to an embodiment of the present invention;

FIG. 7 is a schematic view of a double-walled housing of a device to be protected according to one embodiment of the invention; and

fig. 8 is a schematic view of a double-walled housing of a device to be protected according to another embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following detailed description, reference is made to the accompanying drawings that form a part hereof and in which is shown by way of illustration specific embodiments of the application. In the drawings, like numerals describe substantially similar components throughout the different views. Various specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to practice the teachings of the present application. It is to be understood that other embodiments may be utilized and structural, logical or electrical changes may be made to the embodiments of the present application.

Fig. 1 is a schematic diagram of a tamper circuit according to an embodiment of the present invention, where the tamper circuit includes a first power source X20, a second power source 12V _ in, a detection switch X19, an alarm beep, and an alarm switch, where a first end of the detection switch X19 is connected to an anode, i.e., a power supply end, of the first power source X20, and a second end of the detection switch X19 is connected to a control end of the alarm switch. In the invention, the alarm switch is a switching triode Q1, the second end of the detection switch X19 is connected with the base electrode of the switching triode Q1 through a base electrode resistor, the collector electrode of the switching triode Q1 is connected with one end of an alarm beep, the other end of the alarm beep is connected with the second power supply 12V _ in, and the emitter electrode of the switching triode Q1 is connected with the negative electrode of the first power supply X20. When the detection switch X19 detects that the housing is forcibly opened, the detection switch is closed, the first power supply X20 provides base current for the switching transistor Q1 to make the switching transistor Q1 conduct in saturation, and then the second power supply circuit where the alarm beep is located is switched on, and the alarm beep gives an alarm. In this embodiment, the first power source X20 is two batteries respectively providing 1.5V in series, and the second power source 12V _ in is an input power source of the device to be protected and provides 12V dc voltage. Of course, depending on the power supply parameters of the alarm, it is also possible to use the first power supply or a battery as the second power supply.

The invention gives an alarm when the shell of the device to be protected is forcibly opened so as to prompt that the shell is being opened illegally currently.

In this embodiment, the alarm beep is a buzzer, and may also be an audible and visual alarm, or a detector that sends alarm information, and is connected to the relevant monitoring device. When the shell is forcibly opened, the detector sends out a high level representing alarm information, and after the monitoring device receives a high level signal sent by the detector, the shell of the device to be protected is determined to be forcibly opened, so that an alarm is given, or a power supply of the device is cut off.

The installation position of the alarm can be located in the device to be protected, and can also be installed in a place far away from the device to be protected, such as a monitoring room and the like, so that monitoring personnel can conveniently obtain alarm information immediately.

Further, in order to enable the device to be protected to immediately stop working when being illegally operated, the tamper-proof circuit further includes a device power protector F1 and a first power switch. The first power switch is a switching transistor Q2, the base of which is connected with the positive pole of the first power supply X20 through a detection switch X19, the collector of the switching transistor Q2 is connected with the second end of a power supply protector F1 in the power supply loop of the device, and the emitter of the switching transistor Q2 is connected with the negative pole of the first power supply X20. The power protector F1 may be any type of fuse, such as the socket type fuse shown in fig. 1. The first end of the power supply protector F1 is connected with a power supply of the device to be protected, and supplies power to the circuit of the device after passing through the power supply protector F1. The first terminal of the power protector F1 is also connected to the anode of the second power source X20 through a diode D1.

When the shell is illegally opened, the detection switch X19 is closed, the base of the switching triode Q2 is connected with the first power supply X20, the base current provided by the first power supply X20 enables the switching triode Q2 to enter a saturated state instantly, the collector and the emitter are conducted, and therefore the first power supply X20 and the power supply protector F1 form a closed circuit loop, and therefore the power supply protector F1 is fused due to the fact that excessive current flows instantly, and the power supply loop of a device to be protected is cut off.

Fig. 2 is an external view of a device to be protected to which the tamper circuit of the present invention is applied. The device to be protected is an audio and video physical isolation device and is used for physically isolating audio and video signals of different networks, so that the information of the respective networks is prevented from being leaked. In this embodiment, the device to be protected includes a housing 1, where the housing 1 includes a front panel and a rear panel, and various interfaces are provided on the panels for accessing audio and video signals. The inside of the shell 1 is a circuit of the device, various electrical components are installed on an electrical board, and the electrical board is fixed with a bottom plate of the shell.

The power interface of the device is connected with the power adapter, and the 220V commercial power is converted by the power adapter to provide 12V power supply for the device. The anti-disassembly circuit provided by the invention is connected to the circuit board near the power interface, and the detection switch is arranged at the connecting position of the shell. The detection switch of the present invention is, for example, a D3SH-BIRI model detection switch of OMRON corporation, and its structural schematic is shown in fig. 3, and it is fixed at a proper position of the housing through a device structure 23, and two pins 22 are respectively connected in the circuit. When the casing is opened illegally, the operating lever 21 of the detection switch is pressed down to close the detection switch, thereby giving an alarm and opening the power supply circuit of the device.

The detection switch may be a travel switch or a microswitch, or may be a proximity switch or a hall switch. Fig. 4 is a schematic diagram showing the positional relationship between the housing and the hall switch. The casing 11 and the casing 12 of the device to be protected are buckled with each other, the circuit of the device to be protected and the anti-disassembly circuit provided by the invention are arranged on the circuit board 13, and the circuit board 13 is fixed in the casing 12. The hall switch X30 is fixed to the circuit board 13, and a magnet X31 is attached to the bottom end of a mounting bracket X32 provided on the housing 11. When the housing 11 is separated from the housing 12, the mounting bracket X32 moves along with the housing 11, and the magnet X31 thereon approaches the hall switch X30, so that the hall switch X30 is turned on.

The installation principle of the proximity switch is similar to that of the Hall switch, a stop block for switching on the proximity switch is fixed on the shell and moves together with the shell, and when the shell is opened, the stop block enters the response range of the proximity switch, so that the proximity switch is switched on.

The detection switch can also be a contact switch of a relay, and can also realize the function of the detection switch by matching with a necessary sensor.

The invention also provides an anti-dismantling structure, which comprises a shell of the device to be protected with a special structure, and the anti-dismantling structure is matched with the anti-dismantling circuit, so that the anti-dismantling structure can play a role of alarming when the shell of the device to be protected is illegally operated. As shown in fig. 5, the housing of the device to be protected is a sealing structure, and sealing strips 20 are connected between the housing 21 and the housing and between the housing and the interface 22, so as to ensure that the inside of the housing of the device to be protected is a sealed space. And removing oxygen in the sealed space and filling inert gas. Fig. 6 is a schematic diagram of a detection switch circuit in a circuit matched with the special shell structure. The detection switch circuit includes an oxygen sensor X40 and a detection switch control circuit provided in the sealed space. The detection switch control circuit comprises a single chip microcomputer X41, a switch triode X42 and a relay circuit, wherein the relay circuit comprises a relay coil X43 and a pair of normally open contacts X44. The signal end of the oxygen sensor X40 is connected with one of the input ends of the singlechip X41, one output end of the singlechip X41 is connected with the base electrode of the triode X42, the collector electrode of the triode X42 is connected with a power supply Vcc, the emitter electrode of the triode X42 is connected with one end of the relay coil X43, and the other end of the relay coil X43 is grounded. The normally open contact X44 is used as a detection switch, and as shown in fig. 1, a first end of the normally open contact X44 is connected to the positive electrode of the first power source X20, and a second end is connected to the base electrodes of the switching transistors Q1, Q2 through base resistors, respectively.

The oxygen sensor X40 is located in the sealed space and sends the sensed oxygen concentration value to the single chip microcomputer X41. The single chip microcomputer X41 is internally provided with an oxygen concentration threshold value, the oxygen concentration sensing value is compared with the threshold value, and when the oxygen concentration sensing value is larger than the threshold value, the single chip microcomputer X41 outputs a high level. Under normal conditions, the oxygen concentration in the sealed space is very low, the oxygen concentration sensing value is smaller than the threshold value, and the single chip microcomputer X41 does not output; when the shell is illegally opened, the sealed environment is damaged, external oxygen enters the shell, the sensing threshold of the oxygen concentration sensed by the oxygen sensor is larger than the threshold, the single chip microcomputer X41 outputs high level to enable the triode X42 to be in saturated conduction, so that the collector and the emitter of the triode X42 are connected, the relay coil X43 is connected with a power supply Vcc and electrified, the normally open contact X44 is triggered to be closed, the alarm is alarmed, and the power supply of the device to be protected is switched.

In another embodiment, the housing comprises a double-layer housing, as shown in fig. 7-8, the device to be protected comprises double-

layer housings

31 and 32, the inner space of the device to be protected is divided into two spaces, and the

housings

31 and 32 are sealed by a sealing strip 30, so that one of the spaces is a sealed space 310. In fig. 7, the housing 31 is internally provided with a sealed space 310, and the circuit board 33 is located in a space between the housing 31 and the housing 32. In fig. 8, the space between the housing 31 and the housing 32 is a sealed space 310, and the circuit board 33 has various electrical components 34 mounted thereon and is located in the inner space enclosed by the housing 31. The oxygen sensor is built in the sealed space 310, and the sealed space 310 is filled with inert gas, and the oxygen concentration of the inert gas is less than the preset concentration. When the shell is opened, outside air enters the sealed space 310, the oxygen concentration is increased and exceeds the sensing threshold, the single chip outputs high level to the detection switch, then the alarm is given, and the power supply of the device to be protected can be cut off, so that the device to be protected stops working.

Due to sealing and the like, the inert gas in the sealed space leaks to different degrees, so that the oxygen concentration in the space is increased, and misoperation is caused. To address this problem, in another embodiment, an oxygen scavenger may be disposed within the sealed space filled with an inert gas to maintain the oxygen content within the sealed space below a preset concentration. The oxygen scavenger can be an oxygen scavenger mainly made of an inorganic matrix, for example, reduced iron powder is put into a small bag and is put into a sealed space.

According to the invention, the anti-disassembly circuit is arranged in the shell of the device to be protected, so that an alarm is given when the device is operated illegally, and the power supply circuit of the device can be cut off, so that the device to be protected stops working, and the safety of data transmission of the device to be protected is ensured.

The above embodiments are provided only for illustrating the present invention and not for limiting the present invention, and those skilled in the art can make various changes and modifications without departing from the scope of the present invention, and therefore, all equivalent technical solutions should fall within the scope of the present invention.

Claims

1. An anti-disassembly circuit is arranged in a shell of a device to be protected, wherein the anti-disassembly circuit comprises a first power supply, a second power supply, a detection switch, an alarm and an alarm switch, wherein one end of the detection switch is connected with one end of the first power supply, the other end of the detection switch is connected with a control end of the alarm switch, and the alarm is connected with the alarm switch in series and then connected into a power supply loop of the second power supply; the detection switch is connected with the alarm switch when the shell is forcibly opened, and the alarm gives an alarm in response to the connection of the second power supply circuit.

2. The tamper circuit of claim 1 further comprising a device power protector and a first power switch, one end of the device power protector is connected to the power input of the device to be protected and the power input of the first power source, the other end of the device power protector is connected in the first power supply loop through the first power switch, and the detection switch turns on the first power switch when detecting that the housing is forcibly opened; the power protector opens in response to the current flowing exceeding a threshold.

3. The circuit of claim 2, wherein the alarm switch and the first power switch are triode switch circuits.

4. A circuit according to claim 3, wherein the second power supply is the power supply or the first power supply or a battery of the device to be protected.

5. The circuit of claim 1, wherein the first power source is a battery.

6. The circuit of claim 1, wherein the alarm is a buzzer, an audible and visual alarm, or a detector that emits an alarm.

7. A circuit according to claim 1 wherein the alarm is mounted remotely from the device to be protected.

8. The circuit of claim 1, wherein the detection switch is a travel switch, a micro switch, a proximity switch or a hall switch with a built-in normally open switch.

9. The circuit of claim 1, further comprising an oxygen sensor and a detection switch control circuit, wherein the oxygen sensor is connected to a signal input terminal of the detection switch control circuit, and an output terminal of the detection switch control circuit is connected to the detection switch; when the oxygen sensor senses that the oxygen concentration exceeds a preset value, the output end of the detection switch control circuit is connected with the detection switch.

10. The circuit of claim 9, wherein the detection switch control circuit comprises a single chip microcomputer, a triode circuit and a signal relay, wherein a signal input end of the single chip microcomputer is connected with the oxygen sensor and receives an output signal of the oxygen sensor; the output end of the single chip microcomputer is connected with the base electrode of the triode, the emitting electrode of the triode is connected with the coil of the signal relay, and the pair of normally open contacts of the signal relay is used as the detection switch.

11. The circuit of claim 9, wherein the inside of the housing of the device to be protected is a sealed space filled with an inert gas, the oxygen sensor is disposed in the sealed space, and the oxygen concentration in the sealed space is less than a preset value.

12. The circuit of claim 9, wherein the housing of the device to be protected is a double-layered housing that divides the interior of the device to be protected into two spaces, one of which is a sealed space filled with an inert gas.

13. An electrical circuit according to claim 11 or 12, wherein an oxygen scavenger is provided in the enclosed space filled with inert gas for keeping the oxygen content in the enclosed space below a preset value.

14. A tamper circuit is arranged in a shell of a device to be protected, wherein the tamper circuit comprises a first power supply, a second power supply, a normally open detection switch, an alarm and a first triode, wherein a first end of the detection switch is connected to a first power supply end of the first power supply, and a second end of the detection switch is connected to a base electrode of the first triode through a base electrode resistor; a collector electrode of the first triode is connected with a first end of the alarm, and an emitter electrode of the first triode is connected with a second power supply end of the first power supply; the second end of the alarm is connected with the power supply end of the second power supply; when the shell is opened forcibly, the detection switch is closed, and the alarm gives an alarm.

15. The circuit of claim 14, further comprising a device power protector and a second transistor, a first terminal of the device power protector being coupled to a power input of a device to be protected, a second terminal of the device power protector being coupled to a collector of the second transistor; the base electrode of the second triode is connected with the second end of the detection switch through a base resistor, and the emitting electrode of the second triode is connected to the second power supply end of the first power supply; the first power supply end of the first power supply is connected with the first end of the device power supply protector through a diode; the power protector opens when the housing is forcibly opened.

16. The circuit of claim 14, further comprising an oxygen sensor and a detection switch control circuit, the oxygen sensor being connected to a signal input of the detection switch control circuit, an output of the detection switch control circuit controlling the detection switch; when the oxygen sensor senses that the oxygen concentration exceeds a preset value, the output end of the detection switch control circuit is connected with the detection switch.

17. The circuit of claim 16, wherein the detection switch control circuit comprises a single chip, a third triode circuit and a signal relay, wherein an input end of the single chip is connected with the oxygen sensor and receives an output signal of the oxygen sensor; the output end of the singlechip is connected with the base electrode of the third triode through a base electrode resistor, the emitting electrode of the third triode is connected with the coil of the signal relay, and the collector-emitter electrode of the third triode is connected with the power supply end of the first power supply; and a pair of normally open contacts of the signal relay is used as the detection switch.

18. The circuit of claim 16, wherein the interior of the housing of the device to be protected is a sealed space filled with an inert gas, the oxygen sensor is disposed in the sealed space, and the oxygen concentration in the sealed space is less than a preset value.

19. The circuit of claim 16, wherein the housing of the device to be protected is a double-layered housing that divides the interior of the device to be protected into two spaces, one of which is a sealed space filled with an inert gas.

20. An electrical circuit according to claim 18 or 19, wherein an oxygen scavenger is provided in the enclosed space filled with inert gas for keeping the oxygen content in the enclosed space below a preset value.