EP0215685A2 - Glasbruchdetektor - Google Patents

Glasbruchdetektor Download PDF

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Publication number
EP0215685A2
EP0215685A2 EP86307237A EP86307237A EP0215685A2 EP 0215685 A2 EP0215685 A2 EP 0215685A2 EP 86307237 A EP86307237 A EP 86307237A EP 86307237 A EP86307237 A EP 86307237A EP 0215685 A2 EP0215685 A2 EP 0215685A2
Authority
EP
European Patent Office
Prior art keywords
warning
vibrations
generated
signal
electrical signal
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP86307237A
Other languages
English (en)
French (fr)
Other versions
EP0215685A3 (de
Inventor
Harald Steinbrucker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MAXIMAL ELECTRICAL ENGINEERS Ltd
Original Assignee
MAXIMAL ELECTRICAL ENGINEERS Ltd
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 MAXIMAL ELECTRICAL ENGINEERS Ltd filed Critical MAXIMAL ELECTRICAL ENGINEERS Ltd
Publication of EP0215685A2 publication Critical patent/EP0215685A2/de
Publication of EP0215685A3 publication Critical patent/EP0215685A3/de
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/02—Mechanical actuation
    • G08B13/04—Mechanical actuation by breaking of glass

Definitions

  • This invention relates to detection apparatus, more specifically a glass-break detector alarm device such as is used to warn of intruders tampering with or breaking windows to gain access to a property.
  • One object of the present inventin is to provide a detector which obviates the disadvantages outlined above, more specifically which does not require to be “tuned” to respond to the conditions prevailing in a particular application.
  • the change is preferably represented by a difference signal produced following comparison of a first signal corresponding to the received vibrations and a second signal derived by delaying the first signal for a predetermined period of time.
  • the apparatus attunes after the said predetermined time to any change in the object or its mounting that affects the vibration transmission characteristics of the object.
  • the difference signal disappears. It follows that the apparatus is thus largely independent of the nature or condition of a particular object to be monitored. Irrespective of these considerations or following a predetermined time after a change in the vibration transmission characteristics, a steady state condition is reached, in which no difference signal is generated.
  • the resulting difference signal is recognised and processed to distinguish between events of which a warning is required and transient effects.
  • a window such effects may be caused, for example, by a bird or insect striking a window, by wind or rain, or by a passing vehicle.
  • the difference signal is preferably applied to a discriminator for ascertaining whether any change in amplitude and/or the frequency spectrum of the vibrations received by the transducer occur and/or are sustained for a period of time, which may if required be adjustable and is shorter than the said predetermined time. Only then is the device operable to trigger an alarm.
  • One important advantage of the present invention is that the device can be reset following an alarm caused for example, by an intruder cracking a window pane but failing to gain access and possibly being deterred by the alarm, and will continue to provide effective protection.
  • Figure 1 is a circuit diagram of a glass break detector having a transmitter and a receiver intended to be attached to or otherwise mounted in contact with a window pane, usually at opposite corners thereof
  • Figure 2 is a view of the components of the selective preamplifier.
  • the working voltage (10.4 to 15 V DC, AC portion 110 mVss) is stabilised by the positive voltage regulator IC 1 to 8 V DC.
  • the components D1, D2, L1, C1, C2 constitute the polarity safeguard, act as a screen and protect the circuit against high frequency interference fields as well as interference and over voltage peaks.
  • Transistors T1 and T2 together form an oscillator generating a frequency of approximately 230kHz which can within limits (approx. 10%) be varied by the potentiometer P1 (adaptation to reflection quality).
  • T3 serves to monitor functioning and is operated by a test button.
  • the frequency determining elements are the inductance L2 and capacitors C7, C8.
  • the capacitors are of Styroflex construction to achieve a high frequency stability. This frequency is used to operate a piezo-ceramic unit which converts the electrical oscillations into mechanical vibrations.
  • the mechanical vibrations are tapped, again by means of a piezo unit, forming part of the receiver and is converted to an oscillating electrical signal which is fed to a selective preamplifier 10 consisting of T1, T2 and feedback resistors R2, R3 the frequency determining components constituting the high pass filter which in turn consists of capacitors C3, C4 inductance L1 and resistor R7.
  • a selective preamplifier 10 consisting of T1, T2 and feedback resistors R2, R3 the frequency determining components constituting the high pass filter which in turn consists of capacitors C3, C4 inductance L1 and resistor R7.
  • the now amplified sinusoidal oscillation is applied to a variable-gain amplifier stage consisting of field effect transistor TF1, the selective amplifier consisting of transistors T 4 T 5 and the variable gain amplifier consisting of operational amplifier OP 1.
  • the sinusoidal oscillation is rectified by diodes D 5, D 6, capacitor C 24 and resistor R 34 and fed to the variable gain amplifier OP 1.
  • the potential divider consisting of R 31 and R 32 indicated the desired value of the control arangement.
  • the capacitor C 21 operates thereby as a stabiliser.
  • the capacitor C 22 serves as a storage means and regulates the time lag as a function of the variation in reflection.
  • the gate of the field effect transistor TF 1 is controlled via R 28 by the variable gain amplifier OP 1.
  • the control arrangement operates on U Stab /2. If a variation in reflection typical of a glass breakage occurs and endures for approximately 200 ms, then via C 22, the secondary adjustment is delayed for approximately 1.5 s - for approximately 10 mVss variation in amplitude.
  • There is a differential voltage between desired and actual values and this differential voltage is fed to the level amplifier consisting of operational amplifiers OP 2 and OP 3 and is boosted by a total of approximately 40 dB.
  • the desired value is present at resistors R 35 and R 36.
  • the actual value is tapped by the selective amplifier T 4, T 5, via C 18 and, rectified by D 3, D 4, R 33 and C 23, is fed to the non-inverting input of the operational amplifier OP 2.
  • the operational amplifier OP 3 automatically compensates for temperature and direct current voltage fluctuations. The amplifier output, when at rest, settles down to a level of U Stab /2.
  • the signal level passes to a window discriminator OP 4 and OP 5.
  • the size of the window is determined by resistors R 41, R 42, R 44.
  • the output of the window discriminator is when at rest at a high level but when there is any misalignment of the window discriminator, the output displays a low level potential via the diodes D 7 and D 8.
  • This low level potential is fed to an RS flip-flop comprising G 1 and G 2.
  • the L or low level must be formed via ⁇ from C 35 and R 54 and be present at G 1, otherwise a reset takes place via the diode D 11.
  • the output of the flip-flop G 1, G 2 is applied to the emitter of the transistor T 7.
  • a signal is tapped-off downstream of the selective preamplifier and fed via the diode D 17 and the high pass filter comprising C 14, L 3, C 15 to the thyristor Thy 1 which, when activated, causes operation of the RS flip-flop IC 4 consisting of G 3 and G 4.
  • the output of the flip-flop then shows a low potential. This low potential remains until such time as C 36 is discharged through R 56 and until thyristor Thy 1 is reset.
  • the output of the flip-flop G 3, G 4, inverted, passes through IC 5, G 5 via R 59 to the base of transistor T 7.
  • the emitter of T 7 is set by reflection measurement to a low level potential and the base of T 7 is operated with a high level potential by the frequency measurement.
  • a low level potential is present at the collector of T 7.
  • This low level potential operates the RS flip-flop consisting of G 7 and G 8.
  • the low level potential from the output G 7, G 8 blocks T 6 and the alarm relay falls.
  • the inverter IC 5, G 6, via the thyristor Thy 2 controls the storage unit LED and furthermore ensures that the flip-flop G 7, G 8 remains tipped via Thy 2 until a manual reset (the relay remains dropped for this period).
  • the window discriminator IC 3 consisting of OP 6 and OP 7 constitutes the minimum-maximum monitor. If the limit value is exceeded in a positive or negative direction, then the output of the window discriminator displays a low level potential. This low level potential acts on the flip-flop G 7, G 8 and, during a breakdown, causes the relay to drop and causes the LED 1 to give a display.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
EP86307237A 1985-09-20 1986-09-19 Glasbruchdetektor Withdrawn EP0215685A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8523280 1985-09-20
GB858523280A GB8523280D0 (en) 1985-09-20 1985-09-20 Glass break detector

Publications (2)

Publication Number Publication Date
EP0215685A2 true EP0215685A2 (de) 1987-03-25
EP0215685A3 EP0215685A3 (de) 1989-01-18

Family

ID=10585494

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86307237A Withdrawn EP0215685A3 (de) 1985-09-20 1986-09-19 Glasbruchdetektor

Country Status (2)

Country Link
EP (1) EP0215685A3 (de)
GB (1) GB8523280D0 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9349269B2 (en) 2014-01-06 2016-05-24 Tyco Fire & Security Gmbh Glass breakage detection system and method of configuration thereof

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2056015B2 (de) * 1970-11-13 1973-05-03 Worl, August, 8031 Stockdorf Verfahren und vorrichtungen zur alarmsicherung
DE2541764A1 (de) * 1975-09-19 1977-03-24 Philips Patentverwaltung Ueberwachungsanordnung fuer beschaedigungen an groesseren scheiben mit einer ultraschallvorrichtung
US4088989A (en) * 1975-12-08 1978-05-09 Gulf & Western Manufacturing Company Intrusion detection apparatus
DE3027283A1 (de) * 1980-07-18 1982-02-11 ABM Elektronik GmbH, 8000 München Verfahren und vorrichtung zum anzeigen von glasscheibenbruch
DE3243960A1 (de) * 1982-11-27 1984-05-30 EMS Elektronische Meldesysteme GmbH, 8912 Kaufering Schaltungsanordnung zur anzeige von glasscheibenbruch
GB2143976A (en) * 1983-07-14 1985-02-20 Shorrock Security Systems Ltd Window glass breakage detector apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9349269B2 (en) 2014-01-06 2016-05-24 Tyco Fire & Security Gmbh Glass breakage detection system and method of configuration thereof

Also Published As

Publication number Publication date
EP0215685A3 (de) 1989-01-18
GB8523280D0 (en) 1985-10-23

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Inventor name: STEINBRUCKER, HARALD