WO2009091280A1 - Capteur pour système d'alarme - Google Patents

Capteur pour système d'alarme Download PDF

Info

Publication number
WO2009091280A1
WO2009091280A1 PCT/RU2008/000509 RU2008000509W WO2009091280A1 WO 2009091280 A1 WO2009091280 A1 WO 2009091280A1 RU 2008000509 W RU2008000509 W RU 2008000509W WO 2009091280 A1 WO2009091280 A1 WO 2009091280A1
Authority
WO
WIPO (PCT)
Prior art keywords
comparator
microcontroller
sensor
printed circuit
pulse shaping
Prior art date
Application number
PCT/RU2008/000509
Other languages
English (en)
Russian (ru)
Inventor
Igor Aleksandrovich Razhin
Andrej Anatolevich Shamshurin
Original Assignee
Igor Aleksandrovich Razhin
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Igor Aleksandrovich Razhin filed Critical Igor Aleksandrovich Razhin
Publication of WO2009091280A1 publication Critical patent/WO2009091280A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
    • H03K17/945—Proximity switches
    • H03K17/955—Proximity switches using a capacitive detector

Definitions

  • the invention relates to alarm systems for theft or hacking of various, mainly electrical and electronic products, such as cell phones.
  • a known alarm sensor with a piezoelectric signal transducer with time parameters varying depending on the mechanical effect comprising a piezoelectric element electrically connected to a pulse generating unit, which has a feedback circuit including at least one feedback resistor, and the piezoelectric element is installed in this feedback circuit communication to create a self-oscillating circuit for changing the feedback parameters and time parameters of the output pulse sequence ka formation of pulses during mechanical action on the piezoelectric element (see patent RU Ne2168213, CL G08B 13/02, 11.27.1999).
  • the described sensor has a fairly high sensitivity even in the case of minimal mechanical impact on the guarded object.
  • this sensor is only triggered by mechanical impact on the protected object, which narrows the scope of its use and does not allow it to be used in cases where it is possible to separate any part of the protected object on which the sensor is installed, for example, removal back cover of a cell phone, without mechanical impact on the sensor.
  • an alarm system sensor containing a pulse shaping unit including a microcontroller and a capacitive sensitive element
  • This sensor contains a capacitive-type sensitive element, which allows the sensor to give an alarm even in the absence of mechanical impact on the sensor.
  • the implementation of the sensor in the form of two parallel insulated conductors passing through or around the protected product complicates the use of this sensor and requires the placement of a sensitive element in the protected product, which is not always possible.
  • the problem to which the present invention is directed is the creation of an alarm system sensor that does not require the placement of other elements on the protected product or around it, and therefore does not require the opening of the protected product.
  • the technical result is to simplify the operation and increase the reliability of the sensor of the alarm system.
  • the sensor of the alarm system contains a pulse forming unit including a microcontroller and a capacitive sensitive element, while the comparator included in the microcontroller operates in a multivibrator mode, and the pulse forming unit includes at least two DC comparator resistors, the connection point of which is connected to the direct input of the comparator whose output, which is the output of the pulse forming unit, is connected through a time-setting resistor to the lining of the first capacitor, the inverse input of the comparator, and through p a positive feedback resistor with a direct input of the comparator, and the lining of the second capacitor is connected to the zero bus, moreover, at least two printed conductors of the printed circuit board, on which the pulse forming unit is assembled, form one of the capacitor plates, and the second lining the first and second capacitors are the metal elements of the protected object, to which is attached the bottom side, for example glued, the printed circuit board of the pulse forming unit, while the upper
  • the protected object becomes an integral part of the sensor of the alarm system and any attempt that changes the capacitive relationship originally established when the sensor was mounted on the protected object is fixed by the sensor.
  • Figure l presents a circuit diagram of a sensor of an alarm system. The best embodiment of the invention
  • the alarm system sensor contains a pulse shaping unit including a microcontroller 1, for example, PIC12F629, and a capacitive sensing element 2.
  • the pulse shaping unit is made on a comparator, which is part of the microcontroller, and operating in the multivibrator mode.
  • the following external elements are used - two resistors 3 and 14 for installing a DC comparator, the connection point of which is connected to direct input 5 of the microcontroller 1 comparator, output 6 of which, which is the output of the pulse forming unit, is connected through a timing resistor 10 to the lining of the first capacitor 8 and to the inverse input of the comparator 9.
  • the lining of the second capacitor 7 is connected to a common wire.
  • the output of the pulse forming unit 6 through the positive feedback resistor 4 is connected to the direct input 5 of the comparator of the microcontroller 1.
  • the capacitor plates 7 and 8 form at least two printed circuit wires of the printed circuit board that are not directly connected to each other (not shown in the drawing), on which the pulse forming unit is assembled, and the second lining of the first and second capacitors 7 and 8 are the metal elements of the protected object 11, to which is attached the bottom side, for example, glued on both sides second tape, printed circuit board unit for generating pulses.
  • the structure of the pulse forming unit includes a phototransistor 12, for example KP-3015P ⁇ C connected to the microcontroller 1, to control the illumination of the lower side of the printed circuit board and inside the case.
  • the sensor is connected to the alarm system through a group of contacts 13.
  • the alarm system sensor operates as follows.
  • the sensor is fixed, for example, glued, with the bottom of the printed circuit board to the protected object 11, which allows you to form the capacitance of the capacitors 7 and 8, which is stored in the memory of the programmable microcontroller 1, while these capacitors 7 and 8 together with the resistor 10 form a timing chain.
  • the frequency generated by the multivibrator built into the microcontroller 1, in addition to the capacitance of capacitors 7 and 8, is affected by the comparator’s own capacitance, mounting capacitance, and printed circuit board capacitance, which are constant and can reach several tens of picofarads in total.
  • the sensor software monitors the frequency generated by the multivibrator. When the power is turned on, the initial frequency value is averaged and stored in the memory of microcontroller 1, and then continuously compared with the current read frequency.
  • the capacitance of the capacitors 7 and 8 changes, as a result of which the frequency generated by the multivibrator changes, assembled on a comparator, which is part of the microcontroller 1, where the changed frequency value is compared with the original value.
  • the changed capacitance value is transmitted to the multivibrator, which causes a sharp change in the frequency generated by the multivibrator and the microcontroller after software processing and Frequency change analysis generates an alarm.
  • microcontroller 1 continuously averages the current frequency over the past few minutes and adjusts the value in the memory of microcontroller 1. This is necessary to compensate for the slow drift of the multivibrator frequency due to changes in temperature, humidity, etc.
  • an adaptive algorithm for calculating the sensitivity of the sensor is used. The larger the initial frequency deviation, i.e. the greater the capacitive coupling of the sensor with the object 11, the lower the sensitivity, but at the same time, the likelihood of a false response of the sensor. The lower the capacitive coupling, the greater the sensitivity, but also the higher the likelihood of a false positive. However, the maximum sensitivity value is limited.
  • the ambient light is constantly monitored by means of a phototransistor 12. When the sensor case is opened or the bottom side of the circuit board is exposed and, as a result, the light changes, the sensor is triggered and gives an alarm.
  • the present invention can find application for the protection of various kinds of household goods and electronic equipment in stores and at various exhibitions with free access for visitors and buyers to the demonstrated models of equipment.

Abstract

L'invention concerne le domaine des systèmes d'alarme. Le résultat technique consiste en une meilleure fiabilité de fonctionnement et une facilité d'utilisation. Le capteur comprend une unité de conformation d'impulsions constituée d'un microcontrôleur et d'un élément de détection de la capacitance, un comparateur faisant partie du microcontrôleur et fonctionnant comme un multitivibrateur; l'unité de conformation d'impulsions comprend au moins deux résistances qui sont utilisées pour régler le comparateur en fonction du courant continu et dont le point de raccordement est couplé à l'entrée directe du comparateur dont la sortie, qui est la sortie de l'unité de conformation d'impulsions, est reliée à l'armature du premier condensateur par l'intermédiaire d'une résistance de temporisation, et à l'entrée inverseuse du comparateur et, par l'intermédiaire de la résistance de contre-réaction positive, à l'entrée directe du comparateur. L'armature du second condensateur, quant à elle, est reliée à la barre neutre, l'une des armatures des condensateurs étant formée par au moins deux bandes conductrices, qui ne sont pas directement raccordés entre elles, d'une carte de circuits imprimés sur laquelle est montée l'unité de conformation d'impulsions, et la seconde armature des premier et second condensateurs se présente sous la forme d'éléments métalliques de l'objet protégé auquel est fixée par son côté inférieur la carte de circuits imprimés de l'unité de conformation d'impulsions. Dans le circuit de l'unité de conformation d'impulsions est inclus un phototransistor, raccordé au microcontrôleur, pour la commande de l'éclairage du côté inférieur de la carte de circuits imprimés et de l'intérieur du boîtier.
PCT/RU2008/000509 2008-01-14 2008-08-07 Capteur pour système d'alarme WO2009091280A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
RU2008100212 2008-01-14
RU2008100212 2008-01-14

Publications (1)

Publication Number Publication Date
WO2009091280A1 true WO2009091280A1 (fr) 2009-07-23

Family

ID=40885503

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/RU2008/000509 WO2009091280A1 (fr) 2008-01-14 2008-08-07 Capteur pour système d'alarme

Country Status (1)

Country Link
WO (1) WO2009091280A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2372363A (en) * 2000-12-01 2002-08-21 Peter Gwynne Security device having a capacitive sensor
RU52225U1 (ru) * 2005-09-13 2006-03-10 Закрытое акционерное общество "АРГУС-СПЕКТР" Устройство охранной сигнализации емкостного типа
RU2281558C2 (ru) * 2004-07-12 2006-08-10 Ооо "Алпро" Способ охраны контролируемого предмета и устройство для его осуществления
US20070146142A1 (en) * 2005-12-22 2007-06-28 Checkpoint Systems, Inc. Security tag for cigarette pack

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2372363A (en) * 2000-12-01 2002-08-21 Peter Gwynne Security device having a capacitive sensor
RU2281558C2 (ru) * 2004-07-12 2006-08-10 Ооо "Алпро" Способ охраны контролируемого предмета и устройство для его осуществления
RU52225U1 (ru) * 2005-09-13 2006-03-10 Закрытое акционерное общество "АРГУС-СПЕКТР" Устройство охранной сигнализации емкостного типа
US20070146142A1 (en) * 2005-12-22 2007-06-28 Checkpoint Systems, Inc. Security tag for cigarette pack

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