CN2489411Y

CN2489411Y - Electric theft-proof alarm

Info

Publication number: CN2489411Y
Application number: CN 01242151
Authority: CN
Inventors: 洪浩鹏; 庄静昆
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-06-12
Filing date: 2001-06-12
Publication date: 2002-05-01
Anticipated expiration: 2011-06-12

Abstract

The utility model discloses an electric theft-proof alarm which is trimming-proof and can be programmablely controlled. The alarm comprises a master power supply, a core and buzzer. The core is provided with a micro controller, a theft-proof sensor, a condition set input and an electronic switch. Wherein, the micro controller controls the master power supply to supply power for the buzzer through the electronic switch according to the signals provided by the condition set input and signals received by the theft-proof sensor. The utility model is characterized in that:(1) the buzzer, a reserve electrical power source, an voltage tester circuit and another electronic switch are sealed together to form a buzzer circuit;(2) the core is provided with a sense resistor with one end connected with the master power supply and the other end connected with a down-lead between the core and the buzzer;(3) the voltage tester circuit controls the reserve electrical power source to supply power for the buzzer through the electronic switch according to the electrical signals provided by the core down-lead. Compared with the prior art, the alarm can effectively prevent thieves from stealing a controlled object by firstly destroying the alarm device through destroying the master power supply, the down-lead between the master power supply or the core or the down-lead between the core and the buzzer thus improving the theft-proof performance of the device.

Description

A kind of electronic anti-theft alarm

The utility model is a kind of burglar alarm that is applied to household, office space or vehicle, safety cabinet, relates to the improvement of warning device theftproof performance, says further, is the electronic anti-theft alarm of a kind of anti-trimming, control able to programme.

Existing electronic anti-theft alarm, system passes through the setting state input circuit by the user, set anti-theft state or remove anti-theft state to microcontroller, setting under the anti-theft state, when controlled device occurred stealing feelings, the theft-proof sensor output signal entered microcontroller, by the conducting of microprocessor controls electronic switch, main power voltage adds to hummer by electronic switch, makes it to send loud sound, to show warning.Usually, for the convenience of installing, the main frame system that the primary power of alarm, hummer and microcontroller etc. constitute adopts separate structure, and promptly primary power, main frame, hummer are independent separately, perhaps primary power combine with main frame and with hummer independently.This class alarm all can cause hummer not ring when primary power wrecks or primary power to lead-in wire, main frame to the arbitrary place of the lead-in wire of hummer of main frame cut off, and can not realize reporting to the police.

This electronic anti-theft alarm can be released etc. vibration, heat and report to the police, and himself inside wrecked reports to the police too, thereby compared with prior art, shows its superiority on aspect of performance.

Moreover this alarm can be set by the user in removing anti-theft state, has overcome owing to above-mentioned improvement causes normal maintenance, changes the error that also can report to the police, and it is further perfect that its performance is obtained.

Therefore, at first the purpose of this utility model is that a kind of electronic anti-theft alarm will be provided, this alarm can be monitored in real time to primary power and primary power to the lead-in wire and main frame to the lead-in wire of hummer of main frame, in case primary power wrecks or above-mentioned lead-in wire is cut off, loud alarm sound takes place in hummer too.

Secondly, another purpose of the present utility model be to provide a kind of can be by the user with the alarm of host setting in antitheft disarm state, this alarm can not send the sound again under normal maintenance, situation about changing.

Its first purpose is realized by following scheme:

This alarm comprises primary power, main frame and three parts of hummer at least, host apparatus has microcontroller, theft-proof sensor and setting state input circuit and electronic switch, wherein, the signal that signal that microcontroller provides according to the setting state input circuit and theft-proof sensor obtain, controlling primary power by electronic switch and powering, be characterized in: (1) hummer and standby power supply, voltage detecting circuit, another electronic switch formation buzzer circuit that is packaged together to hummer; (2) in main frame, be equipped with one and detect resistance, the one end is connected in primary power, and the other end is connected in the lead-in wire of main frame to hummer; (3) hummer also by voltage detecting circuit according to the electric signal that main frame lead-in wire provides, controlling standby power supply by electronic switch and powering to hummer.Like this, when by the setting state input circuit with host setting during in anti-theft state, if primary power wrecks or primary power to the lead-in wire and main frame to the arbitrary place of the lead-in wire of hummer of main frame is cut off, all can cause main power voltage can't add to the voltage detecting circuit input end, cause the counter-rotating of voltage detecting circuit output signal, thereby make the electronic switch conducting, hummer gets electric and sends alarm sound from standby power supply.

Second purpose of the present utility model, can realize by increase following feature in such scheme: a, in main frame is provided with a coding circuit by microprocessor controls; B, in buzzer circuit, a decoding scheme of depositing with lock is set; The working power of voltage detecting circuit is deciphered and controlled by another electronic switch to the signal that c, decoding scheme provide according to coding circuit.Like this, when host setting during at anti-theft state, the coding output circuit after decoding scheme decoding, is opened electronic switch with the output encoder control signal, makes voltage detecting circuit get electric work, can monitor the internal sabotage problem of appearance at any time; And when host setting when removing anti-theft state, the coding output circuit will export another coding control signal, decoding scheme is deciphered after, electronic switch cuts out, voltage detecting circuit dead electricity and quitting work, at this moment, maintenance and change primary power and will can not cause false alarm again.

The utility model compared with prior art, except the general utility functions that can realize existing burglar alarm, it can also prevent effectively that the thief from going between by destroying primary power and primary power to main frame lead-in wire or main frame to hummer, warning device is damaged earlier, then steal controlled device again, improved the theftproof performance of device, in addition, this device is by adopting the coding control technology, realized setting up defences and removing, the user can safeguard that under normal circumstances alarm no longer sends the sound to controlled device, makes the performance of alarm obtain further perfect.

Fig. 1 is the circuit block diagram of existing burglar alarm;

Fig. 2 is the utility model circuit block diagram;

Fig. 3 is a kind of concrete enforcement circuit diagram of the utility model.

The utility model is described in further detail below in conjunction with accompanying drawing:

With reference to Fig. 3, primary power is connected with hummer by triode VT0, diode D0, and standby power supply is connected with hummer by triode VT2, might obtain voltage in arbitrary place from two power supplys in order to hummer; Detect resistance R 0 and be connected on the VT0, utilize lead-in wire 3. to make transmission line, main power voltage is caused the input end of voltage detecting circuit as detection signal; Voltage detecting circuit employing voltage comparator integrated circuit LM393 and peripheral cell resistance R 1 thereof, formations such as R2, triode VT1; R1, R2 to the standby power supply dividing potential drop as the LM393 comparative voltage, R0 and D0, hummer to the dividing potential drop of primary power as input voltage; Decoding scheme adopts PT2272-L4, power by standby power supply, only adopt an one data terminal D1 as control end in this example, working power by resistance R 5, triode VT1 control LM393, its address mouth is by coding output circuit form coding, the data input pin DIN of PT2272-L4 be connected to resistance R 3, D1 to lead-in wire 3. with R4 to power supply negative terminal, also be to utilize lead-in wire 3. as the transmission line of coded signal; The coded format that coding output is pressed PT2272 by the P1.0 mouth of microcontroller (single-chip microcomputer) 87LPC762, control the break-make of VT0 through resistance R 7 by the passage of interface circuit ULN2003, when P1.0 output " 1 ", the VT0 conducting, by the DIN end that goes between 3., R3 adds to PT2272-L4, make DIN is high level to main power voltage through VT0, when P1.0 output " 0 ", VT0 ends, and R4 draws DIN and is low level, and diode D1 plays buffer action.Like this, PT2272-L4 can decipher the work of control LM393 by the coding output of the P1.0 mouth of microcontroller.Because the scramble time of PT2272 lacks (several seconds zero point), can not influence the operate as normal of hummer.

The course of work of present embodiment is as follows:

When the user by receive 2 and the state input initialization circuit that constitutes of infrared remote controller 1 when device is set in anti-theft state by infrared, microcontroller is exported a coded signal, after PT2272-L4 decoding, export high level from output terminal D1, make triode VT1 conducting, LM393 obtains operating voltage, at this moment, device is in inside and outside on the alert, if have the thief from the diagram 1., 2., 3., 4. cut off lead-in wire or primary power is destroyed at arbitrary place, position, the in-phase input end of LM393 because of the voltage that can not get primary power less than inverting input, the output terminal output low level, make triode VT2 conducting, the standby power supply electric current hummer of flowing through, hummer sends alarm sound; When the user was set in the releasing anti-theft state with device, microcontroller was exported another coded signal, and after the PT2272 decoding, output terminal D1 output low level is ended triode VT1, the LM393 outage, and at this moment, maintenance, replacing power supply can not make buzzer warning.R6 among the figure is a metering function, and LED is used to compensate output voltage and the indication of LM393.For vibration or the hot monitoring, alarming of releasing, then by P1.0 mouth output high level, the VT0 conducting, main power voltage is added on hummer through VT0, D0, sends warning, and its course of work is consistent with existing alarm.

Above-mentioned example only is that the utility model is implemented to make specific description, can not be understood as a kind of restriction to the invention.Obviously, according to design of the present utility model, industry those skilled in the art all can make corresponding simple conversion, conversion such as coding, decoding scheme, in addition, electronic switch can use field effect transistor, relay, controllable silicon etc. to substitute, and voltage detecting circuit also can be waited and be finished the detection of voltage by time base circuit exclusive disjunction amplifier, logic gates.

Claims

1, a kind of electronic anti-theft alarm, comprise primary power, main frame and three parts of hummer, host apparatus has microcontroller, theft-proof sensor and setting state input circuit and electronic switch, wherein, the signal that signal that microcontroller provides according to the setting state input circuit and theft-proof sensor obtain, controlling primary power by electronic switch and powering, it is characterized in that: (1) hummer and standby power supply, voltage detecting circuit, another electronic switch formation buzzer circuit that is packaged together to hummer; (2) in main frame, be equipped with one and detect resistance, the one end is connected in primary power, and the other end is connected in the lead-in wire of main frame to hummer; (3) hummer also by voltage detecting circuit according to the electric signal that main frame lead-in wire provides, controlling standby power supply by electronic switch and powering to hummer.

According to the alarm of claim 1, it is characterized in that 2, a, in main frame is provided with a coding circuit by microprocessor controls; B, in buzzer circuit, a decoding scheme of depositing with lock is set; The working power of voltage detecting circuit is deciphered and controlled by another electronic switch to the signal that c, decoding scheme provide according to coding circuit.