JPH03226932A - Vibration sensor for burglar preventing instrument - Google Patents

Abstract

PURPOSE:To obtain a vibration sensor capable of exhibiting a high detection capacity with a simple structure by making a rotatable ball of a magnetic material, and detecting the movement of the ball by mean of a Hall element. CONSTITUTION:A Hall element 21 is housed inside a mold body 16. The mold body 16 is provided with a cylindrical cavity 22 containing therein a ball 23 made of a magnetic material. The detection surface of the Hall element 21 is positioned in the inner peripheral surface of the cavity. In consideration that an article is taken out in a bag or the like and that vibration is generated by the movement of the article in case of a burglar, the vibration is detected and light is changed from bright to dark so that an alarm is given under a predetermined condition to warn an operator of the burglar. Since it is sufficient that a vibration sensor electrically detects the vibration, the ball 23 is made of the magnetic material, and the Hall element 21 detects the movement of the ball 23, thus exhibiting a high detection capacity. Therefor, the vibration sensor for a burglary preventing instrument capable of securely detesting the vibration with a simple structure can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration sensor used in an anti-theft device for preventing theft of products, and particularly to a vibration sensor that can reliably detect vibrations with a simple structure.

[Conventional technology]

Conventionally, anti-theft devices consist of a tag that is attached to a product and issues an alarm when it receives a predetermined excitation, and an electromagnetic wave emitter that is installed near the gate of a product sales area and emits electromagnetic waves to excite the tag. The configuration is common.

According to the anti-theft device having such a configuration, when a product with a tag attached passes through the gate of a product sales station, the tag is excited by the electromagnetic waves emitted from the electromagnetic wave emitter, and the tag issues an alarm. It will be done. This makes it possible to prevent product theft.

According to this anti-theft device, the electromagnetic wave emitting device installed near the gate needs to emit strong electromagnetic waves in order to cause the resonator of the tag to resonate. For this reason, it has the disadvantage that it does not comply with the standards that have been revised in recent years in the Radio Law.

Further, according to the above-mentioned theft prevention device, the tag needs to be provided with an antenna that also serves as a resonator in order to receive electromagnetic waves, but the antenna cannot be miniaturized. Therefore, there is a drawback that the entire tag cannot be miniaturized.

In order to eliminate the drawbacks of each of the above systems, the present inventor proposed and filed an application for a miniaturized anti-theft device that does not use electromagnetic waves. The anti-theft device proposed by the present inventor basically detects light and vibration, and when certain conditions are met, it determines that the object has been stolen and issues an alarm. Therefore, the anti-theft device proposed by the present inventor requires a light sensor and a vibration sensor.

[Problems to be Solved by the Invention] However, the main problem that the present inventor faced when proposing the anti-theft device was the vibration sensor. Although it is sufficient to detect vibration electrically as the vibration sensor, there are actually few suitable for this purpose.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a vibration sensor for an anti-theft device that has a simple structure and can reliably detect vibrations.

[Means to solve the problem]

In order to achieve the above object, the vibration sensor of the anti-theft device includes a light sensor that detects the brightness of light, a vibration sensor that detects vibration, and a detection signal from the vibration sensor and a vibration sensor that detects the vibration. and an alarm circuit that issues an alarm when the detection signal from the vibration sensor detects vibration and the detection signal from the optical sensor changes from bright to dark for a certain period of time. This anti-theft device is characterized in that a ball made of a magnetic material is movably disposed on the detection surface of a Hall element.

Here, in the vibration sensor, a Hall element is provided inside a molded body, a circular cavity is provided in this molded body, a ball body made of a magnetic material is arranged in the circular cavity, and a Hall element is provided on the inner peripheral surface of the cavity. The configuration may be such that the detection surface is positioned.

In addition, the vibration sensor includes a Hall element provided inside a molded body, a hemispherical depression provided in the molded body, a ball made of a magnetic material placed in the depression, and a Hall element mounted on the circumferential surface inside the depression. The detection surface may be positioned.

[Function] In the anti-theft device of the present invention, in the event of theft, the perpetrator must put the product in a pocket of clothing or a bag in his or her possession and take it out, and in the event of theft, vibrations are generated to move the product. Focusing on this phenomenon, the system issues an alarm to notify theft when vibrations are detected and the light changes from bright to dark to reach a certain condition. Therefore, vibrations are detected by a vibration sensor, brightness of light is detected by a light sensor, and these are incorporated into an alarm circuit, which issues an alarm when the above conditions are detected.

The vibration sensor used in the anti-theft device is composed of a freely rolling ball made of a magnetic material, and its movement is detected by a Hall element, so it exhibits high detection ability. Furthermore, since the ball body only restricts movement within its circular shape, it has a simple structure and can be made smaller.

〔Example〕 Embodiments of the present invention will be described below based on the drawings.

1 to 9 are diagrams for explaining a first embodiment of the present invention.

Here, FIG. 1 is a perspective view showing a specific usage example of an anti-theft device to which a first embodiment of the present invention is applied. FIG. 2 is a perspective view of an anti-theft device to which the same embodiment is applied. Third
The figure is a perspective view showing a specific example of the same embodiment, FIG. 4 is an exploded perspective view showing the same embodiment, and FIG. 5 is a diagram showing the arrangement of elements of the same embodiment.

In FIG. 1, a clear case 2 is fixed above the anti-theft device 1, and a product 3 such as a compact disc (CD) can be stored inside the clear case 2. At the upper part of the anti-theft device 1 as shown in the figure and inside the clear case 2, the operating section of the microswitch 4 is exposed. The operation part of this micro switch 4 is product 3.
The anti-theft device 1 does not issue an alarm while the button is pressed, and conversely, the anti-theft device 1 issues an alarm when the product 3 is removed from the clear case 2 while the anti-theft operation is in progress. become. Further, an optical sensor 5 is provided on the side surface of the anti-theft device 1. On the side opposite to this optical sensor 5, a battery operation hole and another optical sensor 5 are provided (not shown).

FIG. 2 is a perspective view showing the arrangement of the main components constituting the anti-theft device 1, in which a light sensor 5 is provided on the short side 7 of the rectangular case 6, and the long side 8 is provided with the optical sensor 5. A microswitch 4 is provided at the. The side surface 9 opposite to the short side surface 7 is provided with an operation hole 12 for inserting the button battery 10 into the battery holder 11 as shown by the arrow a in the figure and removing it as shown by the arrow in the figure. ing. Note that when the battery 10 is inserted into the battery holder 11, theft prevention ia1
becomes operational. Furthermore, an optical sensor 5 is provided next to the operation hole 12. And the battery holder 11
A vibration sensor 13 is provided adjacent to.

An IC 14 for processing the operation is provided above the vibration sensor 13, and an electronic buzzer 1 for alarm is provided.
5 is provided.

The detailed structure of the vibration sensor 13 is shown in FIGS. 3 to 5. The vibration sensor 13 is a molded body 16 made of a material such as plastic and has a rectangular shape.
Detection signal lead wires 19 and 20 protrude. A Hall element 21 is embedded inside this molded body 16, and the lead wires 17, 18, .
19 and 20 are connected respectively. Said mold body 1
A circular cavity 22 is bored from one side of the base 24 of No. 6, and a pole 23 made of a magnetic material is placed inside this circular cavity 22, and a plate having the same size and shape as the base 24 is placed inside the circular cavity 22. 25. 25 is bonded to the side surface of the base body 24 with an adhesive or the like to form a molded body 16. Therefore, the pole 23 can freely move inside the circular cavity 22.

Therefore, the movement of the pole 23 can be detected by the Hall element 21, and this can be taken out as an electrical signal from the lead wires 19 and 20.

FIG. 6 is a block diagram showing an example of the circuit of the anti-theft device 1, which includes a microswitch 4 and a light sensor 5.
, a vibration sensor 13 , and an alarm circuit 30 .

The optical sensor 5 has a structure capable of detecting the brightness of light and converting it into an electrical signal, and includes, for example, a photodiode, a phototransistor, a solar cell, and the like.

The vibration sensor 6 has a structure capable of detecting vibration and converting it into an electric signal, and the structure shown in FIGS. 3 to 5 is used. The microswitch 4 makes it possible to electrically detect that the product 3 has been taken out from the clear case 2.

The alarm circuit 30 includes a signal processing circuit 31 and an electronic buzzer 15.
It is composed of. The signal processing circuit 31 takes in the detection signal from the optical sensor 5, the detection signal from the vibration sensor 6, and the detection signal from the microswitch 4,
The electronic buzzer 15 is activated under predetermined conditions. For example, when vibration is detected by the vibration sensor 13, the signal processing circuit FIII
An alarm is generated by sounding the electronic buzzer 15 when the detection signal from 5 changes from bright to dark and a certain period of time has elapsed, or when the product 3 is removed from the clear case 2 by the microswitch 4. emits.

FIG. 7 shows a specific configuration example of the signal processing circuit 31, which includes a vibration signal processing circuit 32 that processes the detection signal from the vibration sensor 13, and a vibration signal processing circuit 32 that processes the detection signal from the optical sensor 5. A noise removal circuit 33 that removes the frequency component of the noise removal circuit 33, a timer circuit 34 that outputs an output signal from the noise removal circuit 33 for a certain period of time, and an electronic buzzer that takes in the signal of the timer circuit 34 or the microswitch 4. Drive circuit 3 that drives 15
It consists of 5.

The vibration signal processing circuit 32 includes a detection processing circuit including an operational amplifier AP and a comparator C1, and a transistor T r
The power supply switching circuit includes transistors T, -Tr2, diodes D1 to D2, capacitor C1, resistors R1 to R5, and an amplifier circuit Q. The vibration signal processing circuit 32 processes the signal output from the vibration sensor 13 with a detection processing circuit, and a holding circuit is driven by the signal from the detection processing circuit, and the power switching circuit is kept in an on state for a certain period of time. Take.

The noise removal circuit 33 includes optical sensors 5, 5 and an input resistor R.
Amplifier circuit Q2 that takes in the photodetection signal from the connection point of the series circuit with 6, resistor R1, and capacitor C2
, a diode D8, an AND circuit Q, and a low-pass filter that cuts noise from the output signal from the amplifier circuit Q2.

The timer circuit 34 includes an input amplifying section composed of an input resistance Re'=, Rq, a transistor T r a, a resistor R1, a diode D4, a capacitor 03, and an AND circuit Q4.
For example, if the input remains at "1" even after 3.5 seconds have elapsed, an output is output from the AND circuit Q.

The drive circuit 35 includes an electronic buzzer switch circuit including an input resistor RI2, a drive transistor TrS, and a resistor R1□.
~RI4, a transistor T□, and a holding circuit that maintains the electronic buzzer switch circuit in an on state using a diode D4.

The operation of the anti-theft device configured as described above will be explained with reference to FIGS. 1 to 9.

FIG. 8 is a diagram simply showing the flow of operation of the anti-theft device 1. As shown in FIG. FIG. 9 is a time chart showing the operation of anti-theft 8!11.

2 First, if the anti-theft device 1 is placed in a stationary state, the vibration sensor 13 detects that the ball 23 is stationary, so
There is no change in the output from the Hall element 21, and the comparator CP is turned off. As a result, transistor T4° is turned off (before time t1 in Figure 9)
. Therefore, since no power is supplied from the button battery 10 to the vibration signal processing circuit 32, noise removal circuit 33, and timer circuit 34, the circuits do not operate (before time t1 in FIG. 9).

However, when the product 3 is removed from the clear case 2 of the anti-theft device 1, the micro switch 4 is turned on, and from then on, the resistance R
, □ ~ RI4, transistor T r4, diode D
The transistor TrS is kept on by the holding circuit consisting of the transistor TrS. Therefore, the electronic buzzer 15 continues to emit a sound even if the product 3 is returned to the clear case 2 (eighth
(See times (6) and (f)).

Next, assume that the product 3 is stolen while it is stored in the clear case 2 of the anti-theft device 1. At this time, it is assumed that the product 3 is placed in a pocket of clothing, for example. Vibration is usually involved in achieving this state. This vibration is converted into an electric signal by the Hall element 21 as the ball 23 inside the cavity 22 of the molded body 16 moves, so the vibration sensor 13 outputs it as an electric signal as the ball 23 moves. (Times in FIG. 8(a) and FIG. 9 are also 1 to tz).

In the vibration signal processing circuit 32, the electrical signal from the ball 23 is amplified by an operational amplifier A and supplied to a comparator CP. The comparator Cp detects a signal having a certain amplitude or more, and supplies an on signal to the diodes D, , D,.

This on signal is diode D. When supplied to sD+,
The transistor TrO is first turned on, and power is supplied from the button battery 10 to the vibration signal processing circuit 32 to the timer circuit 34. At the same time, transistor T r+
is turned on, and thereafter, for a certain period of time from the time when the vibration sensor 13 is turned off (for example, 15 seconds from time t2 in FIG. 9 in this embodiment), the vibration signal processing circuit 32 is turned on and the signal from the battery 10 is Power is supplied to other circuits (times t1 to ts in FIG. 9). As a result, the transistor Tri
is turned on, the transistor Tro is turned on, and power continues to be supplied to the vibration signal processing circuit 32 to the timer circuit 34 (see FIG. 8(c) and times t1 to t5 in FIG. 9).

Of course, while the vibration continues, power from the battery 10 continues to be supplied from the vibration signal processing circuit 32 to other circuits.

In such a state, when light is detected by the optical sensor 5 (see FIG. 8(C) and time t3 in FIG. 9)
, the detection signal has noise removed by the noise removal circuit 33 (see FIG. 6(d)) and is supplied to the timer circuit 34, but since light is detected, the timer circuit 34
doesn't work. However, when power is being supplied in this manner, if the light is blocked due to theft as described above, this will be detected by the optical sensor 5 (see Figure 8 (C)).
, see t3 in FIG. 9), and when the dark state is detected for a certain period of time (also in FIG. 9 from 3 to t4), the timer circuit 34
operates and provides "'1" to the drive circuit 35 (see FIG. 8(e) and FIG. 9 t4). As a result, the drive circuit 35 turns on the transistor Tr5, turns on the transistor Tr4, and thereafter continues to sound the electronic buzzer 15 until the life of the battery 10 is exhausted, regardless of the above-mentioned conditions. Figure 8 (b), Figure 9 time t4
(see below).

In this way, the present embodiment operates to notify theft etc. by sound.

10 to 12 are diagrams for explaining a second embodiment of the vibration sensor according to the present invention.

Here, FIG. 10 is a perspective view showing a second embodiment of the vibration sensor. FIG. 11 is an exploded perspective view showing the same embodiment, and FIG. 12 is a sectional view showing the same embodiment.

The second embodiment shown in FIGS. 10 to 12 is constructed as follows. That is, in the second embodiment of the vibration sensor 13, a molded body 56 is made of a material such as plastic and has a rectangular parallelepiped shape. 59.60 stands out. Then, a Hall element 61 is embedded in the center of the base 64 at the bottom shown in the figure, a hemispherical depression 62 is provided in the base 64 above the detection surface of the Hall element 61, and a ball 63 made of a magnetic material 6 is placed in the depression 62. , a molded body 56 is formed by joining a plate 65 of the same size as the base 64 to the side surface of the base 64 with adhesive or the like so as to close the recess 62.
It consists of

The vibration sensor 13 is installed so that the ball 63 is located at the bottom of the recess 62 (the detection surface of the Hall element 61), and when the entire body moves, the ball 63 rolls, and the Hall element 61 generates an electric current. Vibration is detected by detecting the vibration and taking it out from the detection signal lead wires 59 and 60.

The detection processing circuit of the vibration signal processing circuit 32 used in the second embodiment of the vibration sensor 13 may be one shown in FIG.

FIG. 13 is a perspective view showing still another embodiment of the vibration sensor 13.

The third embodiment shown in FIG. 13 differs from the first embodiment shown in FIGS. 3 to 5 in the following points.

That is, in the third embodiment, the drive current lead wires 77, 78 and the detection signal lead wires 79 are connected from the molded body 76.
．． 80.81.82.83.84.85.86 is projected. Further, four Hall elements 91 are arranged around a circular cavity 92 inside the base 94 of the molded body 76, and a ball 93 made of a magnetic material is placed inside the cavity 92.

In this third embodiment, vibrations can be detected without specifying the detection surface.

In this embodiment as well, the detection processing circuit of the vibration signal processing circuit 32 shown in FIG. 7 can be used.
．． 86 may be used by connecting them in parallel.

Vibrations can also be detected by the vibration sensor 13 configured in this manner.

The vibration sensor 13 used in the anti-theft device 1 has a simple configuration and can reliably detect vibrations.

〔Effect of the invention〕

As described above, according to the vibration sensor of the present invention, the vibration sensor includes a freely rolling ball made of a magnetic material,
Since the movement of this is detected by a Hall element, high detection ability can be demonstrated, and vibrations can be reliably detected with an inexpensive and simple structure.

Further, according to the vibration sensor of the present invention, since movement is only restricted within the circular cavity, a simple configuration and miniaturization are possible.

Further, according to the present invention, since movement is only restricted within the hemispherical depression, a simple configuration and miniaturization are possible.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an anti-theft device to which a first embodiment of the present invention is applied, FIG. 2 is a block diagram showing the entire anti-theft device, and FIG. 3 is a first embodiment of the present invention. FIG. 4 is an exploded perspective view of the same embodiment, FIG. 5 is a sectional view of FIG. 3, and FIG. 6 is a block diagram showing an example of the circuit configuration of the anti-theft device.
FIG. 7 is a circuit diagram showing a specific example of the circuit configuration, FIG. 8 is an explanatory diagram for explaining the operation of the anti-theft device, FIG. 9 is a time chart for explaining the operation of the anti-theft device, and FIG. 10
11 is an exploded perspective view of the second embodiment, FIG. 12 is a sectional view of FIG. 10, and FIG. 13 is a third embodiment of the present invention. FIG. 9 shows an example. 1... Anti-theft device, 2... Clear case, 3...
Product, 4...Micro switch, 5...Light sensor
, 13... Vibration sensor, 16.56.76... Mold body, 21.61.91... Hall element, 22.
92...Cavity, 23.63.93...Ball, 62
...dent. Patent applicant Teio Tsushin Kogyo Co., Ltd. 5 Figure 12 Figure 1 Figure 3

Claims (3)

[Claims] (1) A light sensor that detects the brightness of light, a vibration sensor that detects vibration, and a detection signal from the vibration sensor and a detection signal from the light sensor are captured, and the detection signal from the vibration sensor detects vibration. and an alarm circuit that issues an alarm when the detection signal from the optical sensor changes from bright to dark for a certain period of time, and the detection surface of the Hall element is made of a magnetic material. A vibration sensor characterized by a movable ball body. (2) A Hall element is provided inside a molded body, a circular cavity is provided in this molded body, a ball made of a magnetic material is placed in the circular cavity, and a detection surface of the Hall element is placed on the inner peripheral surface of the cavity. The vibration sensor according to claim 1, characterized in that the vibration sensor is located at (3) A Hall element is provided inside a molded body, a hemispherical depression is provided in this molded body, a ball made of a magnetic material is placed in the depression, and a detection surface of the Hall element is provided on the inner peripheral surface of the depression. 2. The vibration sensor according to claim 1, further comprising a vibration sensor.