WO1987007417A1 - Installation d'alarme - Google Patents

Installation d'alarme Download PDF

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Publication number
WO1987007417A1
WO1987007417A1 PCT/DE1986/000221 DE8600221W WO8707417A1 WO 1987007417 A1 WO1987007417 A1 WO 1987007417A1 DE 8600221 W DE8600221 W DE 8600221W WO 8707417 A1 WO8707417 A1 WO 8707417A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
alarm
oscillator
alarm device
control
Prior art date
Application number
PCT/DE1986/000221
Other languages
German (de)
English (en)
Inventor
Hans-Peter Krug
Original Assignee
Eberhart, Alfred, F.
Bogerd, Marc, G.
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 Eberhart, Alfred, F., Bogerd, Marc, G. filed Critical Eberhart, Alfred, F.
Priority to PCT/DE1986/000221 priority Critical patent/WO1987007417A1/fr
Publication of WO1987007417A1 publication Critical patent/WO1987007417A1/fr

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/26—Electrical actuation by proximity of an intruder causing variation in capacitance or inductance of a circuit

Definitions

  • the present invention relates to an alarm device and a method for monitoring of completely or partially electrically j _5 .leitconnecten bodies, surfaces and der ⁇ same.
  • the alarm device may, for example, 5 not respond to weather influences such as rain, movement of objects by wind or atmospheric disturbances, such as those caused by lightning. Except- The sensitivity of the alarm device must not be affected by changes in the ambient temperature.
  • the present invention therefore has as its object c to create an alarm device which is suitable for the external monitoring of at least partially electrically conductive bodies or surfaces, which is simple and inexpensive to manufacture, and which is designed to prevent malfunctions such as those in particular can be caused by weather influences, are largely avoided.
  • the alarm device according to the invention can be used in connection with all conceivable at least partially electrically conductive objects. These include e.g. B. metallic window frames or window grilles, metallic fly screens, metallic shutters, gates and doors made of metal or with metal applications, metallic fences and any type of metallic building edging, but also objects such as vehicles of all types, airplanes etc. The only prerequisite is that the corresponding objects are electrically isolated from the earth. This must be ensured especially with metallic fences and gates, as well as with vehicles.
  • the alarm device can also be used with non-electrically conductive bodies if the electrical conductivity e.g. is caused by an applied metal foil or by sprayed metal paint.
  • the device can also be used for monitoring individual metallic objects, such as. B. door handles and the like.
  • the invention offers the advantage that an inexpensive alarm device is made available which is composed of standard electronic components. can be set that works reliably and is largely excluded in the event of false triggers, particularly due to weather influences.
  • Circuits known in the prior art can be used for the oscillator. It is preferable to use a triple-feedback sine generator, which is also known.
  • the frequency of the oscillator itself is not critical, however tests have shown that a range between 60 kHz and 250 kHz is preferred. An adjustability of this frequency is also preferred.
  • the sinusoidal signal generated by the oscillator is connected to the object or objects to be monitored.
  • the circuit is connected in a corresponding manner to an earth zero.
  • the voltage of the output signal of the oscillator is preferably below 1 V S / S (i.e. measured from peak to peak), a value of approximately 500 mV S / S is particularly preferred.
  • a suitable point of the oscillator circuit is selected as the measuring point in order to measure the change in the sinusoidal output signal or its breakdown when a person approaches the object to be monitored or when this object is touched. If a triple feedback sine wave generator is used as the oscillator, the emitter of the second transistor or the base of the third transistor which is at the same potential is preferably used as the measuring point.
  • the voltage of this measuring point is preferably set to approximately 1 V S / S.
  • the sinusoidal voltage at this measuring point is then preferably converted into a square-wave signal before further processing.
  • the voltage at the measuring point is kept at a constant value by a subsequent amplitude control using an operational amplifier.
  • the amplitude control contains temperature-dependent electronic components, preferably one or more NTC resistors, with the aid of which the temperature influence from the amplitude control i is eliminated.
  • the feedback of the output signal of the amplitude control to the oscillator is preferably carried out via an optocoupler.
  • the output signal of the operational amplifier used for amplitude control is also fed to the sensitivity control.
  • a timer is started, after which the alarm is triggered.
  • the timer is z. B. set to a value of just under 1 second, so that the alarm is only triggered when the appropriate approach or touch is maintained more than this time. This prevents weather influences, such as. B. rain or lightning or fluctuations in the mains voltage can trigger an alarm, since the duration of these influences is usually in the millisecond range.
  • the time circuit includes an astable multivibrator, the output pulses of which are counted by a decimal counter.
  • an IC connected as a square wave generator e.g. an IC 4011 is used. This embodiment has the advantage over the use of an astable multivibrator that less power is consumed and that the edges are steeper.
  • the counter is preferably connected to a toggle switch arrangement with eight individual switches with which the counting limit and thus the sensitivity can be set. If the count limit is exceeded, the alarm is triggered by appropriate devices such as sirens or light signals.
  • the device according to the invention is preferably fed by an accumulator which is constantly connected to a power supply.
  • This power supply unit supplies the accumulator with its self-discharge current, so that this occurs in the event of a power failure 1 can take over the power supply when fully charged. However, if there is no mains voltage, the supply can also take place via an accumulator alone or via appropriate batteries. 5
  • the invention also has an automatic power failure.
  • This automatic system has the advantage that an alarm when the network is switched on again is avoided after a power failure.
  • This automatic power failure automatic is preferably such that the counting device of the sensitivity control is blocked for a period of a few seconds after the power is switched on again, so that the timer cannot be started, thereby preventing the triggering of an alarm.
  • a Q row of capacitors is provided for the simple adaptation of the device according to the invention to the characteristics of the object to be monitored, which capacitors can be interconnected to different total capacitances via corresponding switches.
  • Mini dip switches are preferably used for this purpose, for example the possibility of combining eight different capacitors.
  • This adaptation can preferably be expanded by providing different ohmic resistances in the input area, which in turn can be selected or combined by appropriate switches.
  • This design not only has the advantage that a Q better fit is achieved to the object characteristics, it is thus possible to suppress to the signal überla ⁇ -enhancing frequencies, including high frequency influences a nearby strong transmitter, or influences of Netzfre ⁇ sequence targeted . 5
  • an oscillator is therefore provided with which a high-frequency AC voltage (for example in the range from approximately 50 to 500 kHz) is generated. This is fed to the object to be monitored. This creates an electrical field surrounding the object.
  • a control voltage within the oscillator is controlled by a control circuit, this control having a predefined time characteristic. If the electrical field is disturbed due to a not very slow approach to the object or a touch, the control voltage changes; the voltage control then enters in action and tries again the control voltage au f to bring the predetermined value.
  • a voltage following the control voltage with only a slight time delay initiates a time measurement when a threshold value is reached, e.g. B.
  • a counting device coupled to a multivibrator, and if the measured time exceeds a predetermined value, e.g. An alarm signal is generated, for example when a certain value is reached in the above counting device.
  • a predetermined value e.g. An alarm signal is generated, for example when a certain value is reached in the above counting device.
  • the time characteristic of the above voltage regulation must be such that the regulation back to the specified value of the control voltage does not take place faster than the above specified value for the time after which the alarm signal is generated.
  • FIG. 1 shows the circuit of the oscillator part and the amplitude and temperature control of an embodiment of the present invention
  • Fig. 3 shows an embodiment of the automatic power failure.
  • Fi. 4 shows a further embodiment of the sensitivity control
  • 5 shows a switching device for adapting the device according to the invention to the object characteristics or for masking out faults.
  • the body 1 to be monitored is symbolically indicated in the left part of the image and is connected to the signal output point 3 via the line 2.
  • the lower horizontal line 4 of the circuit 2 is grounded, while the upper horizontal part 5 of the circuit is kept at a voltage of +12 V with respect to the lower part 4.
  • the voltage supply preferably takes place via a power supply unit, a malfunction due to a power failure being prevented by the automatic power failure automatic described below.
  • the oscillator part is constructed as a triple feedback sinus generator. Since this circuit is known per se in the prior art, it does not need to be described in all its details, the description is therefore limited to the parts essential for the function of the present invention.
  • the resistors 8 and 9 and the capacitors 10 and 11 make it possible to set the frequency of the oscillator. In the illustrated embodiment, this frequency was set at 200 kHz.
  • the measuring point 12 used as the starting point for the amplitude control lies between the emitter of the second transistor 13 and the base of the third transistor 14. With the help of the potentiometers 15, 16 and 17, a voltage of approximately 1 VS / S is input here. poses.
  • the voltage at point 3, the starting point of the circuit for connection to body 1, is then, for example, 550 mV S / S.
  • the voltage at the measuring point 12 drops below the set value until it is built up again by the amplitude control described below, by reducing the emitter resistance of the first transistor 18.
  • the fourth transistor 19 connected downstream of the measuring point serves to convert the sinusoidal signal present at the measuring point into a square-wave signal for the subsequent processing.
  • This fourth transistor 19 is then connected to the amplitude control indicated by II.
  • the square wave signal is rectified and smoothed by the diode 30 in connection with the capacitor 31.
  • the signal is then fed to the operational amplifier 33 via the resistor 32.
  • With the resistor 34 it is set so that it is approximately 7 V, the resistor 35 serves as a feedback resistor.
  • the operational amplifier is set via the potentiometer 36 so that the voltage applied at the measuring point 12 is kept on average at a value of approximately 1 VS / S. If the voltage at the measuring point drops below this value, e.g. For example, when an alarm is triggered or in the event of interference, transistor 37 is blocked by the operational amplifier.
  • the positive voltage from the collector reaches the gate (gate) of the transistor 40 via the NTC resistor 38 via the potentiometer 39.
  • the charging time of the capacitor 47 is set with the aid of the potentiometer 39.
  • the transistor 40 switches the transistor 41 at a frequency of approximately 2 Hz, the light-emitting diode 43 being driven via the resistor 42.
  • the light-emitting diode 43 and the photoresistor 44 are accommodated as optocouplers in a common light-tight housing.
  • the output signal of the optocoupler is in turn fed to the oscillator circuit, the parallel resistor 45 serving to keep the total resistance low. 1
  • the amplitude and temperature control works so that when the light-emitting diode 43 lights up, the emitter resistance of the transistor 18 becomes smaller, as a result of which the voltage at the measuring point 12 increases again.
  • Terminal 50 of the sensitivity control shown in FIG. 2 is connected to terminal 46 of the amplitude control in FIG. 1.
  • the lower horizontal line 51 of the circuit is at ground potential, while the upper horizontal line 52 is at 12 V.
  • the LED 56 is the control display.
  • the transistor 55 When the voltage at the measuring point 12 of the oscillator falls below the 20 preset value and the amplitude control is activated, the transistor 55 is turned on and starts an astable multivibrator which, in a manner known per se, consists of the transistors 57 and 58, the capacitors 59 and 60 and resistors 61, 62, 63 -, c and 64 is formed.
  • the astable multivibrator is designed so that it has a frequency of approximately 6 6 Hz.
  • the decimal counter 65 With the control of the transistor 55, the decimal counter 65 is also put into operation, which counts the pulses gQ emanating from the multivibrator. If transistor 55 is blocked, the counter is reset to zero.
  • the count limit and thus the time period after which the alarm is triggered can be set by the switch device 66, which has eight dip switches.
  • the output signal of the counter is fed via line 67 to a downstream amplifier stage 68, via which the alarm is then triggered with the usual elements, such as. B. a siren or a flashing light.
  • the frequency of the astable multivibrator and the counting limit selected by the switch device 66 are coordinated with one another in such a way that the alarm is triggered when the amplitude control is in operation for a certain period of time.
  • a counting limit of 5 is well suited for trouble-free operation of the alarm device. Interferences, such as those caused by the weather, etc., have not led to false triggering of the alarm device at this sensitivity limit.
  • a particular problem in the operation of the alarm device arises when the alarm device is connected to a conventional network with 50 or 60 Hz via a power supply unit. These difficulties also occur when the device is operated with an accumulator in order to be able to operate even during a power failure.
  • the lower horizontal line 70 of the circuit is in turn at ground potential, the upper horizontal line 71 at a voltage of 12 V.
  • the point 72 of the circuit lies at the positive pole of a * s charging electrolyte encoder of a power supply unit, that is to say before its voltage regulation stage.
  • the voltage at terminal 72 increases by approximately 50% above the value of the voltage supplied by the mains unit, ie at 12 V to approximately 18 V.
  • the collector of transistor 75 which was previously at zero, becomes positive and arrives via capacitor 76 positive pulse to the base of transistor 77, which opens the transistor.
  • the negative pulse of the collector of transistor 77 goes to the input of a timer IC 78, and makes its output positive for about 3 seconds.
  • the positive signal is fed via terminal 79 and terminal 69 to counter 65 of the sensitivity control, namely its switch on / off input (clock enable input) and blocks it until the control has reached normal potential again. This reliably prevents the alarm from being triggered when the network is switched on again.
  • FIG. 4 shows an alternative embodiment of the sensitivity control, the same reference numerals denoting the same parts as in FIG. 2.
  • the transistors 57, 58, capacitors 59 and 60 and resistors 61, 62, 63 and 64 in FIG. 2 existing astable multivibrator circuit is replaced here by an IC 74.
  • This circuit has the advantage over the circuit according to FIG. 2 that the current consumption is reduced and that the edges generated by the circuit are steeper.
  • the output signal of the IC 74 is fed to the IC 65 in the same way as is shown in the embodiment according to FIG. 2.
  • FIG. 5 shows a circuit arrangement which enables the alarm device according to the invention to be easily adapted to the characteristics of the respective object.
  • the capacitor 6 and the resistor 7 in the embodiment according to FIG. 1 are replaced by correspondingly switchable capacitor and resistor arrangements.
  • a circuit arrangement 80 with eight mini-switches is provided, the circuit inputs being combined and leading to point 3 of the circuit as described in FIG. 1.
  • the output terminals of the switching device are connected to individual capacitors 81 to 88, the outputs of which in turn are combined and in the same way with the resistors 9 12 and 8 and the capacitor and the transistor 13 are connected, as in FIG. 1.
  • This circuit arrangement makes it possible to connect one or more capacitors 81 to 88 in parallel. The user therefore has a large number of possible combinations with which he can easily adapt the alarm device to his particular needs.
  • a further switching device in FIG. 5 is designated 90 and is connected to four capacitors 91 to 94 and four resistors 95 to 98.
  • This circuit arrangement replaces the resistor 6 in FIG. 1.
  • This arrangement has the advantage that it can be used to filter out interference frequencies which are generated very specifically by the network or by high-frequency transmitters scattering into the alarm device. A large number of combinations are again available to the user in order to optimally adapt the alarm device to the application. If such an adaptation should not be necessary, the dashed area 99 in FIG. 5 can be replaced by a single resistor.
  • the method for monitoring electrically conductive bodies implemented with this device thus proceeds as follows: A small high-frequency voltage is applied to the objects to be monitored, the maintenance of which is controlled by a suitable measured value. When this voltage drops, the voltage is reduced to its original value. If the time required for the adjustment exceeds a predetermined time period, an alarm is triggered. Temperature differences that can affect the individual circuit elements are compensated for by temperature-sensitive electronic components.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

L'installation d'alarme est destinée à surveiller un objet ayant au moins une partie électriquement conductrice au moyen d'un oscillateur produisant une tension alternative haute fréquence. Cette tension est transmise à l'objet à surveiller. Un système de régulation d'amplitude, qui compense aussi l'effet de variation de température, commande une tension de contrôle de l'oscillateur et déclenche un circuit temporisé lorsque la tension de contrôle s'écarte d'une valeur préréglée. Si l'écart de la tension de contrôle persiste au-delà d'un certain temps fixé d'avance, l'alarme est déclenchée.
PCT/DE1986/000221 1986-05-28 1986-05-28 Installation d'alarme WO1987007417A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/DE1986/000221 WO1987007417A1 (fr) 1986-05-28 1986-05-28 Installation d'alarme

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/DE1986/000221 WO1987007417A1 (fr) 1986-05-28 1986-05-28 Installation d'alarme

Publications (1)

Publication Number Publication Date
WO1987007417A1 true WO1987007417A1 (fr) 1987-12-03

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ID=6790313

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1986/000221 WO1987007417A1 (fr) 1986-05-28 1986-05-28 Installation d'alarme

Country Status (1)

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WO (1) WO1987007417A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995012185A1 (fr) * 1993-10-29 1995-05-04 Hansson Goeran Detecteur capacitif et systeme d'alarme
CN106547666A (zh) * 2016-11-18 2017-03-29 广西大学 电脑主机过热报警器

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1616021B1 (de) * 1968-02-21 1970-12-10 Wö~1, August, 803I Stockdorf Schaltungsanordnung zur Verhinderung von Fehlalarmen bei Überwachungsanlagen
US3697971A (en) * 1970-12-30 1972-10-10 Siegfried Domin Alarm system
US4091367A (en) * 1974-02-28 1978-05-23 Robert Keith Harman Perimeter surveillance system
US4287513A (en) * 1979-05-03 1981-09-01 International Quartz Ltd. Door knob alarm device
US4325058A (en) * 1980-06-11 1982-04-13 Gentex Corporation Pre-intrusion detection and alarm system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1616021B1 (de) * 1968-02-21 1970-12-10 Wö~1, August, 803I Stockdorf Schaltungsanordnung zur Verhinderung von Fehlalarmen bei Überwachungsanlagen
US3697971A (en) * 1970-12-30 1972-10-10 Siegfried Domin Alarm system
US4091367A (en) * 1974-02-28 1978-05-23 Robert Keith Harman Perimeter surveillance system
US4287513A (en) * 1979-05-03 1981-09-01 International Quartz Ltd. Door knob alarm device
US4325058A (en) * 1980-06-11 1982-04-13 Gentex Corporation Pre-intrusion detection and alarm system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995012185A1 (fr) * 1993-10-29 1995-05-04 Hansson Goeran Detecteur capacitif et systeme d'alarme
US5764145A (en) * 1993-10-29 1998-06-09 Hansson; Goran Capacitive detector device and alarm system
CN106547666A (zh) * 2016-11-18 2017-03-29 广西大学 电脑主机过热报警器

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