CN2154506Y

CN2154506Y - Anti-theft card

Info

Publication number: CN2154506Y
Application number: CN 93236886
Authority: CN
Inventors: 朱陵生; 陈建军
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-18
Filing date: 1993-05-18
Publication date: 1994-01-26
Anticipated expiration: 2003-05-18

Abstract

The utility model relates to an anti-theft card, comprising a pitch rate detecting circuit, a peak examining and judging circuit, an intermittent and audio frequency oscillating circuit, and a drive circuit. Due to the adoption of the pitch rate detecting circuit of an electromagnetic induction type, the anti-theft card has high sensitivity. When a protective object clipping tinfoil moves away from the anti-theft card beyond 50 mm, the anti-theft card can judge that the protective object is stolen and alarm. In addition, as the peak examining and judging circuit is adopted and all the functions are completed by a manifold block, a resistor, and a capacitor, the anti-theft card has the advantages of small size, and light weight; the anti-theft card is convenient to carry; the anti-theft card is suitable for the theft protection of wallets or other important documents which are carried about.

Description

Anti-theft card

The utility model relates to the alarm class, is a kind of Anti-theft card specifically.

At present, the burglar alarm kind is a lot, but all exists many weak points, and as a class antitheft device of being made up of transmitter, receiver, volume is big, be unfavorable for carrying, and sensitivity is low, and the best use of is apart from 2～3 meters of need; The antitheft device of another kind of band lead uses very inconvenient.

The purpose of this utility model then is the problem at above-mentioned existence, has designed a kind of electromagnetic induction principle that utilizes, and surveys the range information between protected object and the Anti-theft card, is handled subsequently, judges whether to have things stolen, if Anti-theft card stolen and the automatic audible alarm of energy.

Technical solution of the present utility model:

A kind of by the range sensing circuit, circuit is declared in the peak value inspection, intermittently, audio oscillator circuit, the Anti-theft card that driving circuit is formed, it is characterized in that declaring in the circuit at range sensing circuit and peak value inspection, one of electromagnetic induction coil L terminates to 2 pin of ic chip 1-1, the other end links to each other with the common point A of capacitor C and adjustable resistance Rw, the other end of RW links to each other with the common point B of 3 pin of resistance R 1 and ic chip 1-2,4 pin of IC1-2 connect the negative pole of diode D1, the positive pole of D1 links to each other with the common point C of resistance R 2 with 5 pin of capacitor C 2 and ic chip 1-3, and 6 pin of IC1-5 connect the negative pole of diode D2, and the positive pole of D2 is then received intermittently, audio oscillator circuit.

Advantage of the present utility model:

The utility model is owing to adopt induction range sensing circuit, thereby highly sensitive, will be determined stolen beyond the protection thing that accompanies the tin thin paper leaves this Anti-theft card 50mm and reports to the police; In addition owing to adopted peak value inspection to declare circuit, and all functions add that by an integrated package resistance, electric capacity finishes, thereby volume is little, and are in light weight, are easy to carry, and are very suitable for the thief-proof of wallet or other vital document of carrying.

Fig. 1 is the utility model electrical schematic diagram.

Below in conjunction with accompanying drawing the utility model is further described:

The utility model is by the range sensing circuit, circuit is declared in the peak value inspection, intermittently, audio oscillator circuit, driving circuit is formed, wherein the range sensing circuit is to utilize electromagnetic induction principle, in wallet or the vital document carried, fold up a sizeable tin thin paper, the LC oscillator of forming by electromagnetic induction coil L, ic chip 1-1, capacitor C 1 in coil L, vibrate an electromagnetic field and in addition radiation.When the tin thin paper of reaction protected object locus near or during away from Anti-theft card; because the eddy current effect of metallic tin; thereby the electromagnetic property of electromagnetic induction coil L changes; the input end that is reacted to oscillator will obtain the waveform that amplitude changes with respect to the Anti-theft card space length with protected object; also promptly between oscillation amplitude and relative distance, set up a funtcional relationship; declare by inspection that oscillation amplitude just can be judged wallet or whether the vital document carried is stolen; the peak value inspection is declared circuit and is finished this function exactly; thereafter intermittently; audio oscillator circuit, driving circuit is declared the triggering F work of circuit output signal and is made piezoelectricity peak toot device YD send chimes of doom in the peak value inspection.

Its circuit analysis is as follows:

When the protection thing is stolen.IC1-1 input end waveform amplitude is enough big.Export to IC1-2 through Rw, R1 dividing potential drop, then IC1-2 output just has waveform.This waveform obtains a low level through D1, R2, C2 rectification, is high level by the IC1-3 reverse transformation again.This moment, D2 did not oppositely work.Then the squegger formed of R3, C3, IC1-4 just starting of oscillation form square wave about 1HZ.This square wave is modulated to the sinusoidal wave last modulating wave that forms of audio frequency that audio frequency oscillator that R4, C4, IC1-5 form shakes and by D3, C4 amplitude modulation, add to piezoelectricity buzzer YD through driving circuit IC1-6 and just send too chimes of doom, wherein adjustable resistance Rw is used to be provided with sensitivity.

Claims

1, a kind of by the range sensing circuit, circuit is declared in the peak value inspection, intermittently, audio oscillator circuit, the Anti-theft card that driving circuit is formed, it is characterized in that declaring in the circuit at range sensing circuit and peak value inspection, one of electromagnetic induction coil L terminates to 2 pin of ic chip 1-1, the other end links to each other with the common point A of capacitor C and adjustable resistance Rw, the other end of Rw links to each other with the common point B of 3 pin of resistance R 1 and ic chip 1-2,4 pin of IC1-2 connect the negative pole of diode D1, the positive pole of D1 links to each other with the common point C of resistance R 2 with 5 pin of capacitor C 2 and ic chip 1-3, and 6 pin of IC1-6 connect the negative pole of diode D2, and the positive pole of D2 is then received intermittently, audio oscillator circuit.