Unauthorized Entry Indicator And Method

Abstract

A preferred apparatus for practicing the method comprises silicon controlled rectifiers with anode gate triggering incorporated in a two mode alarm device that can be attached to the inside of a door. Audible mode indicates by the emittance of a penetrating sound perceived by someone on the inside of the door that it is being opened. Radio frequency mode indicates by the absence of a signal, received on a portable radio outside the door, that the door was opened after the mode switch was locked and left.

Description

BACKGROUND OF THE INVENTION

Alarm systems have little utility for tenants of high-rise apartment dwellings. The use of the conventional alarm device is usually prohibited by the apartment management because of the impediment to maintenance personnel and the illegal and disturbing sound level during testing and accidental or false triggering of the alarm. If permission is given, spare keys and instructions for disabling the alarm must be given to the building management, thus, lessening security because of the possibility of lost keys and dishonest personnel.

SUMMARY OF THE INVENTION

The invention shifts emphasis from protecting property to protecting tenants from harm by indicating that the apartment has been violated and the intruder may still be present, or is being violated and appropriate action must be taken.

This new philosophy enables the design of a device that eliminates the disadvantages of the conventional alarm. An explanation of the operation of the invention will make the advantages of the invention clear. For simplification, we will assume that the apartment is inaccessible except through the door. If the tenant is in his apartment and wishes protection from a sneak intruder, he turns the key operated switch of the invention to audible mode and removes the key to any inconspicuous location. If there is a knock on the door, the door can be opened without triggering the alarm by holding a push button depressed during the time the door is opened. If the door is opened without the push button being depressed, a penetrating, but not illegally loud, sound is emitted and cannot be quieted without the key operated switch being switched to radio frequency mode. Most intruders will make a rapid departure; if not, the tenant is at least forewarned and can take appropriate action.

To prevent triggering of the audible mode by maintenance or management personnel when the tenant is away, the invention switched to audible mode will not allow the tenant to leave without triggering. However, after triggering, the key operated switch is immediately switched to radio frequency mode. The tenant has unavoidably tested the invention and battery condition, and leaves taking the key with him.

Upon returning, the tenant can tell within ten feet of his door if it has been opened in his absence by listening to any portable radio tuned to the radio frequency of the invention. If he hears the modulated signal, he can be certain that his door has not been opened. If he does not hear the signal, he should not proceed without checking with the apartment manager to find whether maintenance personnel have been, or are, in his apartment, and then take appropriate action if needed. Assuming the signal is heard, the tenant opens the door and the device automatically and silently turns off.

It should now be apparent that the method and apparatus of this invention is applicable to other security locations, such as top-secret rooms or buildings, storage closets, filing cabinets, and the like. In certain instances, it may be necessary to employ an external antenna where the device is protecting a particularly well shielded area, such as a metal file, safe, or vault.

With the foregoing in mind, it is an object of the invention to provide a combination sonic frequency-radio frequency (SF-RF) alarm type indicator. Another object of the invention is the provision of such an apparatus which automatically signals if left in the SF mode, thereby serving to indicate its alarm capabilities, as well as to alert the user to shift the key to the RF position.

A further object of the invention is the provision of a method primarily for protecting a person, as contrasted with prior art methods for protecting only personal property. A further object of the method is to insure that the user operates the device properly, and is aware of its operational state.

Yet another object of the invention is to provide a circuit absolutely capable of minimum power drain although maintaining the apparatus continuously in an operational state in one or the other mode, if desired. A feature of the invention resides in the fact that the circuit is switched off from the RF mode when the door is opened and at the user's option may be programmed to the SF mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of the operational components and configuration of the invention and shows graphically the relationship of the component subcircuits, and the implied sequence of operation.

FIG. 2 is a schematic of the circuit of the invention and provides reference points for following the written description of the circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The method and broad block diagram components may best be understood from the general arrangement of FIG. 1. It may be seen that both a remotely detectable source of energy and a locally detectable source of energy are provided. The former is preferably a Radio Frequency Energy Generator A and the latter a Sonic Frequency Energy Generator B. The RF-SF Mode Selector Switch C is provided for past and present indications. A control relay D (which may ground the circuitry) is shown as the block labeled Bistable Relay to Turn Sonic Generator on or Radio Frequency Generator off and it is partially under control of a Manually Held Switch E which permits opening of the door without changing the relay state.

The two blocks F and G may comprise separate windings for operating the relay D, or alternatively, may comprise a single on/off switch for operating a more sophisticated electronic device capable of the functions required in block D. In any event, block F turns off the relay when the door is initially opened, thereby disabling the RF generator A so that the user detects the absence of the RF signal to indicate that the door had been opened.

On the other hand, with the circuit in the SF mode, the block G is provided to turn on relay D, permitting sonic frequency generation at B whenever the door is opened and thereafter until a key is used to switch Mode Selector Switch C back to the RF position.

The functions and operations of the invention are accomplished by the following circuit. The total circuit of the invention is composed of various subcircuit arrangements. The total circuit is most easily understood if the subcircuits are described separately.

Modulated Radio Frequency Energy Generator Arrangement: Resistor 1, capacitor 2, and SCR 3 form a relaxation oscillator whose energy, stored in capacitor 2, is rapidly fired into the tank circuit of inductor 4 and capacitor 5 causing it to ring at the tuned radio frequency. SCR 3 fires at an audio rate, therefore, giving the effect of a modulated radio frequency generator. SCR 3 fires because resistor 6 and resistor 7 form a voltage divider that determines the static potential of the anode gate 8, the anode 9 potential climbs toward supply voltage and when it exceeds the anode gate 8 potential by about 0.7 volt, SCR 3 fires. When capacitor 2 is sufficiently discharged, SCR 3 falls out of conduction because resistor 1 cannot provide adequate holding current, and the cycle repeats.

It should also be appreciated that the radio frequency energy source could, with some alteration of the circuit, be changed to an energy source of a different character, such as an ultralow frequency sound to be detected by a special device or a simple light arrangement that could be seen through a window or under the door.

Sonic Frequency Energy Generator Arrangement: Resistor 10, capacitor 11, and SCR 12 form a relaxation oscillator whose energy, stored in capacitor 11, is fired through resistor 13 into the base of transistor 14 causing transistor 14 to discharge a portion of low impedance energy stored in capacitor 15 through the speaker 16 to ground. Resistor 17, in conjunction with capacitor 15, constitutes a high impedance input to the light-duty batteries 33 and 34. SCR 12 fires because resistor 18 and resistor 19 form a voltage divider that determines the static potential of the anode gate 20, the anode 21 potential climbs toward supply voltage, and when it exceeds the anode gate 20 potential by about 0.7 volt, SCR 12 fires. When capacitor 11 is sufficiently discharged, SCR 12 falls out of conduction because resistor 10 cannot provide adequate holding current, and the cycle repeats.

Mode Selector Arrangement: Key operated switch 22A and 22B selects either radio frequency 30 mode of operation or sonic frequency 31 mode of operation. These switches may be the same single switch, but are shown separately to simplify the circuit connections.

Turn On Arrangement: Key operated switch 22A provides continuity between the anode gate 23 of SCR 24 and ground through the normally closed momentary contact push button switch 25, and the normally closed (when the door is opened) magnet 26B actuated switch 26A. SCR 24 turns on because the anode 27 is more than 0.7 volt higher in potential than the anode gate 23.

Turn Off Arrangement: Resistor 28 provides charging current for capacitor 29 when SCR 24 is conducting provided key operated switch 22A is in radio frequency mode position 30, and normally closed momentary contact push button switch 25, or normally open (when the door is closed) magnet 26B actuated switch 26A is in an open state. SCR 24 turns off when the charged capacitor 29 discharges to ground through normally closed momentary contact push button switch 25 and the normally closed (when the door is open) magnet 26B actuated switch 26A, thus, reverse biasing SCR 24 to accomplish turn off.

Remote Actuating Arrangement: The commercially available switch 26A includes a spring 35 which will maintain the switch closed in the absence of magnet 26B. It will now be appreciated that the invention may be used as an indicating device for areas having more than a single access, each of which may require guarding. Thus, as many normally open switches as may be desired can be connected in parallel with switch 26A, as shown by switch 36, with takeoff leads 37 and 38 provided for additional switches. Thus, the windows and the doors of a house, for example, could be used to suppress the RF signal whenever any access is violated. Similarly, if the device is in the SF mode, the opening of any closure would initiate the sonic alarm.

Authorized Entrance Arrangement: The door, activating magnet 26B actuated switch 26A, may be operated without affecting the turn on circuit or the turn off circuit provided normally closed momentary contact push button switch 25 is held open during the open door condition.

SCR 24 Maintenance Current Arrangement: Resistor 6, in series with resistor 7, provides unbroken current flow to SCR 24 when the key operated switch 22B is being switched from the sonic generator position 31 to the radio frequency generator position 30, therefore, preventing unavoidable turn off of SCR 24 during the transition.

Extraneous Noise Suppression Arrangement: Capacitor 32 provides a short circuit for noise potentials between the anode 27 and the anode gate 23 that could randomly turn on and off SCR 24.

Power Supply Arrangement: Battery 33 and battery 34 are in series to provide a total of 18 volts supply voltage.

The above described circuit achieves absolute minimal current drain, such that the batteries 33 and 34 may operate the circuit in the RF mode for periods substantially corresponding to their shelf life, and then the batteries may be replaced at minimal cost because they are conventional nine volt transistor radio batteries. Also, even if for some reason the circuitry is left inadvertently in the SF mode, it is calculated that the alarm would sound for several days. In order to achieve this unusual type of efficient operation, the following components are used:

Ref. no. Manu- of FIG. 2 Component facturer Stock no. Resistor 1 220K 2 Capacitor 0.005 MFD 3 SCR GE D13T1 4 Inductor Miller 2002 5 Capacitor 230 UUFD 6 Resistor 220K 7 Resistor 220K 10 Resistor 47K 11 Capacitor 1 MFD 12 SCR GE D13T1 13 Resistor 20 14 Transistor Motorola MPS U01 15 Capacitor 200 MFD 16 Speaker Quam 21/2" 8 ohm 17 Resistor 500 18 Resistor 1K 19 Resistor 10K 22 A/B Switch- Key operated Smith 1038 DPDT 24 SCR GE D13T1 25 Switch Switchcraft 103 SPST- NC 26 A/B Switch & magnet combination Alco RS24NC SPST- NC 28 Resistor 10 MEG 29 Capacitor 2.5 MFD 32 Capacitor 0.1 MFD 33 Battery Eveready 216 9 volt 34 Battery Eveready 216 9 volt 36 Switch SPST- NO

from the foregoing description, it may be appreciated that the circuit of FIG. 2 could just as well be arranged to initiate transmission of the RF frequency when the closure is violated. Similarly, it will be seen that the RF and SF oscillator could comprise a single oscillator which could be tuned to operate in the RF or SF mode. In addition, any violation of the closure in the RF mode could signal the local desk in an apartment house or even the local police department over electrical leads in order that the premises could be checked to determine whether the entry was unauthorized. Naturally, the user would enter and switch the mode or otherwise disable the remote actuated alarm signal, but even in the absence of a remote alarm, the device positively signals illegal entry or entry by someone other than the user and thus eliminates the problem of guessing whether an assailant lies in wait or whether or not the apartment was violated regardless of whether it was left locked or unlocked.

Claims

What is claimed is:

1. The method of signaling present violation of a closure by an intruder during one period and indicating past violation of said closure during a different period comprising the steps of: establishing an off condition of a first frequency radiation substantially at the beginning of said one period wherein violation of the closure during said one period changes the off condition to an on condition; signalling said on condition audibly in a manner intended to frighten off said intruder; establishing one of two conditions including the presence and absence of a different frequency radiation during said one period wherein violation of the closure changes the established condition; and detecting the changed condition in a predetermined secretive manner to learn of the violation.

2. The method of claim 1 wherein the one of two conditions are established by generating a radio frequency, and wherein said first frequency radiation comprises an audio frequency.

3. The method of claim 2 further comprising the step of maintaining the audio frequency regardless of the condition of the closure.

4. The method of claim 3 comprising the further step of interrelating the radio frequency generation and the audio frequency generation to require first audio frequency generation before enabling of the radio frequency generation.

5. Apparatus for indicating past violation of a closure by an intruder comprising in combination switching means actuable by violation of the closure; means for generating an audible first frequency radiation in response to present violation of the closure during the first period under control of said switching means; said audible first frequency radiation being designed to frighten off the intruder; and means for establishing one of two predetermined conditions not apparent to the intruder including the presence and absence of a different frequency radiation during a different period; said last mentioned means being responsive to the closure switching means to switch its condition upon violation of the closure. 6The apparatus of claim 5 wherein the means for generating a first radiation comprise audio frequency generating means, and the means for establishing one of two conditions comprise radio frequency generating

means. 7. The apparatus of claim 5 further comprising mode selector switch means for selectively enabling either the means for generating the first

radiation or the means for establishing one of two conditions. 8. The apparatus of claim 5 wherein the means for generating a first frequency radiation and the means for establishing one of two conditions includes a common connection; and means for interrupting said common connection when

a violation occurs during said different period. 9. The apparatus of claim 8 comprising mode selector switch means for enabling either the means for generating the first radiation or the means for establishing one of two conditions; and means for rendering the means for interrupting operative to complete the common connection in response to the mode selector switch

means when in the first radiation generating mode. 10. The apparatus of claim 5 wherein said switching means actuable by violation of the closure comprises a plurality of switches connected in parallel for respective

location at accesses to the closure. 11. Signaling apparatus for guarding a closure from an intruder comprising in combination means actuable upon violation of the closure; silent memory means responsive to said actuable means for secretively indicating past violation of the closure; and separate audible means responsive to said actuable means for indicating present violation of the closure in a manner alarmingly different from the past violation indication.