CN203366339U - Notebook computer anti-theft device - Google Patents

Abstract

The utility model is an anti-theft device for a notebook computer, which comprises an independent power supply, a voltage stabilizing circuit, an electronic switch lock, an infrared ranging sensor, a signal amplifying circuit, an A/D analog-to-digital converter, a signal processing circuit and a buzzer which are sequentially connected. ; The power supply provides the power supply voltage, and the output voltage is stabilized by the voltage stabilizing circuit; the electronic switch lock is connected between the voltage stabilizing circuit and the infrared distance measuring sensor, and the closing/opening of the electronic switch lock determines whether or not it will stabilize The working voltage output by the voltage circuit is transmitted to the infrared distance measuring sensor; the infrared distance measuring sensor detects the distance between the anti-theft device and the external object in real time, and sends the analog voltage signal reflecting the detected distance value to the signal amplifier circuit for amplification, and then sends it to The analog voltage signal is sent to the A/D analog-to-digital converter for analog/digital conversion, and finally sent to the signal processing circuit for processing; the signal processing circuit compares the currently received distance value with the distance value received and stored last time. When the value exceeds the preset safety range, an activation signal is sent to the buzzer.

Description

Anti-theft device for laptop

technical field

The utility model relates to an anti-theft device for a notebook computer, in particular to an anti-theft device based on an infrared distance measuring sensor based on a triangulation principle, and belongs to the application technology of an anti-theft device for a notebook computer.

Background technique

With the development of economy and technology, notebook computers, personal tablet computers, etc. have gradually entered thousands of households. Notebooks have the advantage of being small and light, and this advantage has also become a shortcoming that notebooks are difficult to keep. There are many types of notebook anti-theft devices in the domestic market, but they are basically used for anti-theft in stores and display occasions, and the price is relatively high, so they are not suitable for personal notebook computers. Moreover, it is basically connected to the host through a USB data cable, which limits the layout and scope of the store, and is meaningless for personal laptops to prevent theft. Notebook anti-theft technology has developed from simple BIOS encrypted boot and Windows encrypted boot to hardware anti-theft keyhole, mobile alarm, and even wireless remote locking. Laptop anti-theft technology can be divided into two categories: active defense and passive anti-theft. Passive defense mainly refers to software anti-theft, and its function is to protect its data from being stolen after the laptop is lost. In terms of active defense, its main products are special anti-theft locks and anti-theft alarms. The product we designed belongs to the active defense category, and it is a new application-type economical anti-theft product that plays an alarm role when items are stolen.

Utility model content

The purpose of this utility model is to provide a notebook computer anti-theft device in consideration of the above problems. The utility model not only has a simple structure, but also has low cost, simple operation and obvious anti-theft effect.

The technical solution of this new type is: a notebook computer anti-theft device, including an independent power supply connected in sequence, a voltage stabilizing circuit, an electronic switch lock, an infrared distance measuring sensor, a signal amplification circuit, an A/D analog-to-digital converter, and a signal processing circuit and a buzzer; the power supply provides a power supply voltage, and outputs an operating voltage after being stabilized by the voltage stabilizing circuit; the electronic switch lock is connected between the voltage stabilizing circuit and the infrared ranging sensor, and the electronic switch lock Closing/opening decides yes/no to transmit the working voltage output by the voltage stabilizing circuit to the infrared distance measuring sensor; the infrared distance measuring sensor detects the distance between the anti-theft device and the external object in real time, and will reflect the analog voltage of the detected distance value The signal is sent to the signal amplification circuit for amplification, and the analog voltage signal amplified by the signal amplification circuit is sent to the A/D analog-to-digital converter for analog/digital conversion, and the digital signal after the analog/digital conversion by the A/D analog-to-digital converter sent to the signal processing circuit for processing; the signal processing circuit compares the currently received distance value with the distance value received and stored last time, if the difference between the currently received distance value and the distance value received and stored last time exceeds the preset When the safety range is set, a start signal is sent to the buzzer.

As an improvement of the above technical solution, the infrared distance measuring sensor uses the principle of triangulation to measure the distance between the anti-theft device and the external object in real time.

As an improvement of the above technical solution, the analog voltage signal of the infrared distance measuring sensor has a nonlinear relationship with the distance value detected by the infrared distance measuring sensor in real time.

As an improvement of the above technical solution, the electronic switch lock is a key-type electronic switch.

As an improvement of the above technical solution, the A/D analog-to-digital converter and the signal processing circuit are integrated on a single-chip microcomputer.

As an improvement of the above technical solution, the power supply voltage provided by the power supply is 6V, and the output working voltage after being stabilized by the voltage stabilizing circuit is 5V.

As an improvement of the above technical solution, the power supply is formed by connecting two 3v common type button batteries in series.

As an improvement of the above technical solution, the signal processing circuit includes a memory, and when the distance value currently received by the signal processing circuit is inconsistent with the distance value received and stored last time, the currently received distance value is replaced by the last received distance value. The stored distance value is stored in the memory.

The notebook computer anti-theft device of the utility model is based on the triangulation principle of the infrared ranging sensor, detects the distance between the anti-theft device and external objects (for example, the desktop on which the notebook computer is placed, etc.) in real time, and passes the detected distance value through simulation The non-linear output of the voltage signal is then sent to the signal processing circuit for judgment after the signal amplification circuit and the A/D analog-to-digital converter on the single-chip microcomputer perform signal amplification and analog-to-digital conversion. The received distance value is compared with the last received and stored distance value. If the difference between the currently received distance value and the last received and stored distance value exceeds the preset safety range, the buzzer alarm will be triggered to achieve anti-theft Function. The utility model has the advantages of high integration, convenience and practicality, simple operation and obvious anti-theft alarm function. The utility model is an economical anti-theft device with ingenious design, excellent performance, convenient use, integrated sensor and mechanical and electronic technology. The utility model is suitable for use in school libraries, coffee bars, classrooms and other public places. After the device is connected to a notebook computer, the alarm effect is obvious when the notebook is moved illegally. Because of its small size, it can be built into a USB flash drive. It is a very stylish laptop anti-theft device that is very suitable for individual users such as students and businessmen.

Description of drawings

Fig. 1 is a structural block diagram of the utility model;

Figure 2 is a schematic diagram of the triangulation principle of the infrared ranging sensor.

Specific implementation method

The circuit structure of the notebook computer anti-theft device of the present utility model is as shown in Figure 1, and the notebook computer anti-theft device of the present utility model comprises an independent power supply 1, a voltage stabilizing circuit 2, an electronic switch lock 3, an infrared ranging sensor 4, Signal amplification circuit 5 , A/D analog-to-digital converter 6 , signal processing circuit 7 and buzzer 8 . The power supply 1 provides a power supply voltage of 6V, and outputs a working voltage of 5V after being stabilized by the voltage stabilizing circuit 2 . The electronic switch lock 3 is connected between the voltage stabilizing circuit 2 and the infrared distance measuring sensor 4, and the closing/opening of the electronic switch lock 3 determines whether or not the working voltage output by the voltage stabilizing circuit 2 is transmitted to the infrared ranging sensor 4. The infrared distance measuring sensor 4 detects the distance between the anti-theft device and the external object in real time, and sends an analog voltage signal reflecting the detected distance value (non-linear relationship with the distance value detected by the infrared distance measuring sensor 4 in real time) to the signal The amplifying circuit 5 amplifies, and the analog voltage signal amplified by the signal amplifying circuit 5 is sent to the A/D analog-to-digital converter 6 for analog/digital conversion, and the digital signal after the analog/digital conversion by the A/D analog-to-digital converter 6 sent to the signal processing circuit 7 for processing. Signal processing circuit 7 compares the distance value currently received with the distance value received and stored last time, if the difference between the distance value received currently and the stored distance value received last time exceeds a preset safety range (for example, 4cm- 8cm), a start signal is sent to the buzzer 8 to trigger the buzzer 8 to alarm, thereby realizing the anti-theft function. The utility model can monitor the change of the distance between the device and external objects, and judge whether it is moved illegally. If the device is moved illegally in the working state, a loud alarm will be issued.

Preferably, the signal processing circuit 7 includes a memory (not shown in the figure), and when the distance value currently received by the signal processing circuit 7 is inconsistent with the distance value received and stored last time, the currently received distance value is replaced The stored distance value received last time is stored in the memory.

Preferably, the A/D analog-to-digital converter 6 and the signal processing circuit 7 are integrated on a single-chip microcomputer.

Preferably, the power supply 1 can be formed by connecting two 3v ordinary button batteries in series.

Preferably, the electronic switch lock 3 is a key-type electronic switch. The on-off of the main circuit is realized by inserting and pulling out the key, and its working principle is relatively simple. When the key is inserted into the electronic switch lock, the key is equivalent to a very large resistance across the main circuit, so that the current of the working circuit cannot pass through, thereby realizing the closing of the main circuit (equivalent to the electronic switch lock 3 being disconnected). When the key is pulled out, the main circuit is connected, and the circuit works normally (equivalent to the electronic switch lock 3 being closed).

In this embodiment, the infrared ranging sensor 4 measures the distance between the anti-theft device and external objects in real time based on the principle of triangulation. The triangulation principle based on the infrared ranging sensor is shown in Figure 2. The infrared emitter emits an infrared beam at a certain angle. When it encounters an external object (for example, the desktop on which the laptop is placed, the ceiling in the room, etc.), the beam will be reflected return. After the reflected infrared light is detected by the CCD detector, an offset value L will be obtained. Using the triangular relationship, after knowing the offset distance L, the central moment X, and the focal length f of the filter, you can use the formula (1) The distance D from the sensor to the object can be calculated

Formula 1)

In the formula: D is the distance from the infrared ranging sensor 4 to the anti-theft device to the surface of the external object, L is the offset distance, X is the central moment, and f is the focal length of the filter.

Then, the analog voltage signal value reflecting the real-time detected distance value D is sent to the signal processing circuit for judgment through the signal amplification circuit and the A/D analog-to-digital converter successively after signal amplification and analog/digital conversion. When the difference between the distance value received and stored last time exceeds a preset safety range (for example, 4cm-8cm), an activation signal is sent to the buzzer 8 to trigger the buzzer 8 to alarm.

The utility model can realize the distance measurement of the anti-theft device installed with the infrared distance measuring sensor, and the working state of the anti-theft device is controlled by the electronic switch lock. When the anti-theft device is installed on the laptop, the whole anti-theft device can be activated after the key is pulled out from the lock, and the anti-theft work can start. When the laptop is moved illegally, the anti-theft device connected to the laptop will also follow If it is moved, then, when the distance between the anti-theft device and the external object changes beyond the safe range value, the buzzer will be triggered to generate an alarm. And when the key is inserted into the electronic switch lock, the anti-theft device does not work.

The working principle of the utility model is as follows: the power supply 1 provides an initial voltage of 6v, and outputs a working voltage of 5v after the voltage stabilizing circuit 2, when the electronic lock switch 3 pulls out the key, the main circuit of the entire anti-theft device is connected, and the infrared distance measuring sensor 4 Work in real time, detect the distance between the current anti-theft device and external objects (for example, the desktop on which the laptop is placed, etc.) The analog voltage signal value of the ranging sensor is amplified and converted into a digital signal value and stored as the first detected distance value; then, the infrared ranging sensor 4 continues to work in real time, and the real-time detected distance value ( Analog voltage signal) is sent to the STC12C5410AD series single-chip processor for processing. The single-chip processor compares the currently received distance value with the last received and stored distance value. When they are inconsistent, the currently received distance value will replace the last time Receive the stored distance value to store in the memory; at the same time, if the difference between the currently received distance value and the last received and stored distance value exceeds a predetermined safety range (such as 4cm-8cm), the single-chip processor outputs an instruction , the signal is input to the buzzer 8 after being amplified by the current, the alarm device is started, and the buzzer 8 sounds. When the mechanical electronic lock is inserted, the main circuit is disconnected, and the anti-theft device does not work.

The utility model has been described above in conjunction with the best embodiments, but the utility model is not limited to the above-disclosed embodiments, but should cover various modifications and equivalent combinations based on the essence of the utility model.

Claims (8)

1. a notebook computer anti-theft device, it is characterized in that, comprise the power supply (1), mu balanced circuit (2), electronic switch lock (3), infrared distance sensor (4), signal amplification circuit (5), A/D analog to digital converter (6), signal processing circuit (7) and the hummer (8) that connect successively; Described power supply (1) provides supply voltage, and carries out output services voltage after voltage stabilizing by described mu balanced circuit (2); Described electronic switch lock (3) is connected between mu balanced circuit (2) and infrared distance sensor (4), and the closure of electronic switch lock (3)/disconnection determines that Yes/No sends the operating voltage of mu balanced circuit (2) output to infrared distance sensor (4); Described infrared distance sensor (4) detects the distance of anti-theft device and external object in real time, and the analog voltage signal of the distance value that reflection is detected sends to signal amplification circuit (5) and is amplified, analog voltage signal after signal amplification circuit (5) amplifies sends to A/D analog to digital converter (6) and carries out mould/number conversion, and the digital signal after A/D analog to digital converter (6) mould/number conversion sends to signal processing circuit (7) and processed; Described signal processing circuit (7) compares the current distance value received and the last distance value that receives storage, when if the distance value received current surpasses default safe range with the last difference that receives the distance value of storage, to described hummer (8), send enabling signal.

2. notebook computer anti-theft device according to claim 1, is characterized in that, described infrared distance sensor (4) is measured based on principle of triangulation in real time to the distance employing of anti-theft device and external object.

3. notebook computer anti-theft device according to claim 1, is characterized in that, the distance value that the analog voltage signal of described infrared distance sensor (4) and infrared distance sensor (4) detect in real time is nonlinear relationship.

4. notebook computer anti-theft device according to claim 1, is characterized in that, described electronic switch lock (3) is the key-type electronic switch.

5. according to the described notebook computer anti-theft device of claim 1 to 4 any one, it is characterized in that, described A/D analog to digital converter (6), signal processing circuit (7) are integrated on single-chip microcomputer.

6. notebook computer anti-theft device according to claim 1, is characterized in that, the supply voltage that described power supply (1) provides is 6V, and the operating voltage of by described mu balanced circuit (2), being undertaken exporting after voltage stabilizing is 5V.

7. notebook computer anti-theft device according to claim 6, is characterized in that, described power supply (1) is in series by two common model button cells of 3v.

8. notebook computer anti-theft device according to claim 1, it is characterized in that, described signal processing circuit (7) comprises storer, when the current distance value received of described signal processing circuit (7) and the distance value of last time reception storage are inconsistent, the distance value of the current last reception of distance value replacement received being stored is to deposit in described storer.

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