US3609741A

US3609741A - Prevention of unauthorized movement of articles between predetermined areas

Info

Publication number: US3609741A
Application number: US809259A
Authority: US
Inventors: Wendell S Miller
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-03-21
Filing date: 1969-03-21
Publication date: 1971-09-28
Anticipated expiration: 1988-09-28

Abstract

A system for indicating an attempt to move an article, such as a piece of baggage or an article of merchandise, between predetermined areas, by providing a radio transmitter and radio receiver between the areas, and providing on the article a device having electrical circuitry adapted to receive from the transmitter a signal at a first frequency, and retransmit a radio signal of changed frequency, with the receiver being constructed to respond to and indicate the presence of the return signal. A person authorized to move the baggage or other article may have a key adapted to disable the circuitry against transmission of the changed frequency signal, or otherwise alter the signal, in a manner indicating to the receiver his authorization.

Description

United States Patent [72] inventor Wendell S. Miller 1341 Comstock Ave., Los Angeles, Calif. 90024 [21] Appl. No. 809,259 [22] Filed Mar. 21, 1969 [45] Patented Sept. 28, 1971 [54] PREVENTION OF UNAUTHORIZED MOVEMENT 0F ARTICLES BETWEEN PREDETERMINED AREAS 16 Claims, 6 Drawing Figs.

[52] US. Cl 340/280, 325/8, 325/29, 340/152 TR, 340/171, 340/224, 340/276 [51] Int. Cl. ...G08b 13/14 [50] Field of Search 340/152 TR, 312, 258, 280, 276, 224, 420, 421,171; 325/8,16, 21, 29

[56] References Cited UNITED STATES PATENTS 3,098,971 7/1963 Richardson 340/258 3,175,047 3/1965 Borberg 340/280 3,299,424 1/1967 Vinding 340/258 3,478,344 11/1969 Schwitzgebel et al. 340/280 3,493,955 2/1970 Minasy 340/280 Primary Examiner-John W. Caldwell Assistant Examiner-J. Michael Bobbitt Attorney-William P. Green ABSTRACT: A system for indicating an attempt to move an article, such as a piece of baggage or an article of merchandise, between predetermined areas, by providing a radio transmitter and radio receiver between the areas, and providing on the article a device having electrical circuitry adapted to receive from the transmitter a signal at a first frequency, and retransmit a radio signal of changed frequency, with the receiver being constructed to respond to and indicate the presence of the return signaL A person authorized to move the baggage or other article may have a key adapted to disable the circuitry against transmission of the changed frequency signal, or otherwise alter the signal, in a manner indicating to the receiver his authorization.

1 PREVENTION OF UNAUTHORIZED MOVEMENT OF ARTICLES BETWEEN PREDETERMINED AREAS BACKGROUND OF THE INVENTION This invention relates generally to apparatus and methods for indicating whether a particular person is authorized to move a certain piece of baggage or other article between two different areas.

In the baggage room of an airport or the like, great difficulty is encountered in attempting to maintain any effective control against unauthorized removal or theft of a suitcase from the area. Large numbers of bags frequently arrive at the pickup zone simultaneously, and must be distributed to many different travelers in a very short period of time with minimum inconvenience to the travelers. Attempts to compare check numbers at an exit location have resulted is such excessive slowing of the overall rate of movement of baggage and persons through the area that in many airports all such attempts at checking have been abandoned.

Similarly, in a store or other establishment having merchandise or other articles on display at accessible locations, it is very difficult to detect an attempt at removal of an article from the store or from a particular area of the store. The article may be completely concealed by the taker within a handbag, box, piece of clothing, or the like, in a manner rendering it almost impossible to detect the article as it is carried from the store.

SUMMARY OF THE INVENTION The present invention provides apparatus and methods for indicating very rapidly and conveniently whether a person who is attempting to move a particular article, such as a suitcase, item of merchandise, identification badge, or the like, between two areas, is authorized for such movement. The indication of authorization or nonauthorization may be given in any desirable manner, as by an audible or visual signal, by opening or closing a door or gate at an exit or entrance loca tion, or in any of numerous other ways.

The desired monitoring result is attained by providing radio equipment at or near the controlled area which coacts with a very simple device on the bag or other article in a manner giv ing the indication of authorization or nonauthorization. The circuit on the article may be a miniaturized extremely low cost integrated circuit, which may be energized completely by power received from the primary radio equipment near the exit location, without the necessity for provision of a supplementary power source on the individual articles being controlled.

In applying the present invention to the control of baggage and certain other types of articles, I preferably provide in conjunction with the circuitry on the bag a control unit or control means which is actuable only by an authorized person, and which upon actuation will indicate to the fixed radio equipment that the person is authorized. For example, this control unit may take the form of a key which is carried by the authorized person, and is capable of converting the circuitry on the bag or other article to a condition indicating authorization of the person using the key. Alternatively, a combination lock or other control unit may be substituted for the key.

For maximum simplicity, the circuitry carried by the article being controlled desirably constitutes a transponder circuit which is adapted to receive a radio signal of predetermined frequency from a fixed transmitter at the exit location, and which then transmits a response signal at a changed frequency to which the fixed receiver is tuned. ln most instances, the frequency emitted by the transponder circuitry may be a multiple or harmonic of the original received frequency, in which event a simple rectifier circuit may function to change the frequency. It is also contemplated, however, that other frequencies may be emitted by the transponder, such as a subharmonic frequency or a nonharmonic frequency produced by a heterodyne circuit in the transponder in which two frequencies received from the main transmitter are mixed to produce sum and difference frequencies.

BRIEF DESCRIPTION OF THE DRAWING The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawing, in which:

FIG. I is a diagrammatic representation of an airport baggage area, or other area to which the invention is to be applied;

- FIG. 2 illustrates fragmentarily-in perspective a suitcase which may be located within the baggage area of FIG. l, and which carries a response circuit for indicating when an attempt is made to remove the bag by an unauthorized person;

FIG. 3 is a greatly enlarged fragmentary section taken on line 3-3 of FIG. 2, and showing a key positioned within the bag carried device of FIG. 2;

FIG. 4 illustrates diagrammatically the circuitry of the bag carried device;

FIG. 5 shows the preferred wave form of the two radio signals utilized in the apparatus; and

FIG. 6 shows a variational form of the invention which is adapted for attachment to an article of merchandise, and which may not be key actuated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the FIG. 1 diagram, a room or area to be policed by equipment embodying the present invention is illustrated generally at 10, being bounded by walls I], and typically having entrance 12 through which persons may enter the room, and an exit opening or doorway 13 through which persons leave the room. As exemplary of one preferred use of the invention, the room or area 10 may be considered as constituting a baggage reception area in an airport or the like, having a conveyor represented at 14 along which the individual bags 15 are advanced into the room and onto a support surface or platform 16 from which the individual tourists may select their various bags. After a person has obtained all of his baggage from the platform 16, he leaves the room through exit 13, and in doing so must pass certain stationary equipment 17 positioned adjacent the exit doorway for determining whether the person attempting to remove a particular piece of baggage is authorized to do so. For coaction with the stationary equipment 17, individual pieces of baggage are provided with a transponder unit 18 (FIGS. 2 and 3) which is preferably controlled by a key 19 kept in the possession of the person owning the bag.

The fixed equipment 17 adjacent or near exit 13 includes a radio transmitter 20 which emits a preferably continuous and unchanging radio wave of a predetermined frequency, desirably a frequency within one of .the industrial bands. In FIG. 5 the sinusoidal voltage curve of that wave emitted by transmitter 20 is represented at 21. Also near or adjacent exit opening 13 there is provided a stationary radio receiver 22 (FIG. 1), which is tuned to receive and respond to a radio wave of a predetennined frequency different than that emitted by transmitter 20. Preferably, receiver 22 is responsive only or primarily to a radio wave whose frequency is a predetermined multiple or harmonic of (desirably the second harmonic of) the radio wave emitted by transmitter 20. An indicating unit 23 is controlled by receiver 22 and is energized to produce an appropriate indication when a signal of the predetermined harmonic frequency is received by receiver 22. The indicator unit 23 may typically be a horn, bell, or other audible signal, a light, sign or other visual signal, or any other type of indicator whose energization indicates to an attendant that a particular person carrying a bag past transmitter 20 and receiver 22 is not authorized to do so. Alternatively or supplementally, the indication of authorization or nonauthorization may be given by automatic actuation of a turnstile 24 or other gate structure at the exit location between passing and nonpassing conditions, under the control of receiver 22 in accordance with its reception or nonreception of the predetermined harmonic frequency. It is contemplated that the indications given by the system may function in any of numerous manners, to indicate by energization of the audible or other signal either that the person is authorized or not authorized, as desired, and either to actuate a turnstile or gate from a normally open or passing condition to a closed or nonpassing position when an unauthorized person attempts to leave the area, or alternatively to actuate a normally closed or nonpassing turnstile or gate to an open or passing condition when an authorized person desires to leave.

The transponder units or devices 18 carried by the individual bags are designed to receive the radio signals emitted by transmitter 20, and to respond thereby to transmission of a changed radio signal of the particular type to which receiver 23 is tuned. As previously indicated, this signal to which the receiver is tuned is preferably a harmonic of the signal received by device 18 from fixed transmitter 20, for best results the second harmonic. To produce the second harmonic, the device 18 may rectify the signal from transmitter 20, as represented by the sinusoidal wave 21 of FIG. 5, to the pulsating direct current condition illustrated at 25 in FIG. 5, in which the frequency of pulsating wave 25 is twice that of wave 21. The full wave rectified current is then passed through a transmitting antenna to transmit a radio wave from the device 18 to receiver 22 at the second harmonic frequency.

FIG. 4 shows schematically at 26 a typical electrical circuit for the device 18. This circuit includes a receiving antenna coil represented at 27, which feeds into a bridge-type full wave rectifier circuit 28, whose rectified output in the form of pulsating direct current as represented at 25 in FIG. 5 is passed through a transmitting antenna coil 29. The rectifier circuit includes four individual rectifier elements 30, typically of the solid-state variety.

Structurally, the entire circuit 26 illustrated in FIG. 4 may be formed as a very inexpensive highly miniaturized integrated circuit, formed on a single typically rectangular very thin and small chip 31 of silicon or the like, on which the various components are formed by appropriate painting or deposition techniques (see FIG. 3). More particularly, the antenna coils 27 and 29 may be painted on the silicon body 31 as thin lines of aluminum paint or other conductive material extending about the silicon ship and along its outer surface. The diodes or rectifiers 30 may be formed by appropriately doping localized portions of the surface of the silicon with N" and P material, as at the locations designated 30 in FIG. 3. The electrical connections between the various parts, like the coils, are formed by aluminum or other conductive lines painted on the surface of chip 31. The chip 31 and its circuitry elements may be completely encapsulated within a molded body 32 of electrically insulative material, such as a suitable resinous plastic material, defining an insulative wall 33 at the underside of the circuitry elements engageable with the outer surface of the suitcase, and defining a wall 34 at the upper or outer side of the chip 31 and its carried circuit. This encapsulating insulative body 32 may have flanges extending about its periphery at 35, secured to the suitcase by fasteners 36 or otherwise. It is also contemplated that the device may be secured to the suitcase by adhesive, or in any other convenient manner.

Above wall 36 formed by the insulative encapsulating material, this material forms and defines an elongated slot 37, which is opened only at its left end 38, and into which the previously mentioned key 19 is slidably receivable in the closely confined and accurately located relation illustrated in FIG. 3. This key is normally in the possession of the owner of the suitcase, and is inserted into slot 37 at the time that the owner receives his bag from support platform 16 of FIG. I, to thereby place the device 18 in a condition for indicating to the radio equipment 17 at the exit opening 13 that the person carrying the bag is authorized to remove it from the area.

In the particular arrangement illustrated in FIG. 3, the key 19 is assumed to be formed of an electrically insulative material, such as a suitable rigid resinous plastic material, except at the location of two electrically

conductive metal inserts

39 and 40. These inserts are engageable with

contacts

41, 42, 43 and 44 projecting upwardly from the circuitry formed on integrated circuit chip 31, so that when the key is in the FIG. 3 position, metal element 39 will engage and form a short circuit between contacts 411 and 42, while element 40 will engage and form a short circuit between

contacts

43 and 44. From the schematic representation of FIG. 4, it will be apparent that the contacts then form short circuits across both of the

antenna coils

27 and 29, and thereby disable circuit 26 against functioning as a transponder in the previously discussed manner. The circuit 26 will then not serve to transmit any radio signal in response to reception of the signal from fixed transmitter 20.

To now recapitulate the manner of use of the device illustrated in FIGS. 1 to 45, assume that transmitter 20 is functioning continuously to emit a radio signal of a predetermined radio frequency, and that receiver 22 will respond only to the second harmonic of that frequency. Also assume that the various bags 15 being delivered onto platform 16 from conveyor 14 are provided with transponder devices of the type illustrated at 18, but that these devices are ineffective to transmit any substantial detectable signal to receiver 22 when the bags are in the right-hand portion of the room 11 of FIG. I. The transmitter 20 may if desired be made directional, to aim its transmission primarily across the exit doorway in the direction indicated at 45 in FIG. I, while the antenna of receiver 22 may be made similarly directional to receive radio signals best and primarily in the direction indicated at 46 in FIG. 1. Also, the intensity of the transmitted signal, the sensitivity of receiver 22, and the components of circuit 26 of the transponder devices 18 may all be so selected and designed as to enable the receiver 22 and indicator 23 to respond only to the devices 18 individually, as each separate bag is carried out of the exit opening 13.

If an unauthorized person picks up one of the bags 15 from the location as and attempts to carry it from the room through exit opening 13, the signal emitted by transmitter 20 will be received by antenna 27 of the device 18 on that particular bag, will be rectified by the full wave rectifier 28, and will cause transmission of a response signal of doubled frequency from antenna 29 to receiver 22. The receiver in turn will energize indicator 23 to emit an audible or visual signal, or the like, indicating to an attendant that an unauthorized removal of the bag has been attempted. If the person is the true owner of the bag, on the other hand, he merely inserts key 19 into slot 37 of FIG 3, to form a short circuit across both of the

coils

27 and 29 in a manner disabling the circuit, As previously described, so that device 18 cannot transmit the harmonic frequency signal, and indicator 23 is not actuated. The receiver 22 is of course tuned accurately to the harmonic frequency, and includes filter circuits which filter out the fundamental frequency of transmission of the transmitter 20, and all other unwanted frequencies, so that there is no response of the receiver and indicator unless the precisely predetermined harmonic frequency is received. Also, transmitter 20 must be filtered effectively to produce a pure fundamental frequency, without harmonics, so that the signal from the transmitter cannot in any way serve to directly actuate the receiver, without the interaction of frequency doubling transponder device 18.

Instead of disabling the circuitry, the key 19 or its equivalent may upon insertion serve to convert the circuit from a disabled condition to an active condition, to transmit a signal for reception by receiver 22 only when the key is inserted, and thereby indicate authorization rater than nonauthorization of the person. Also, as previously indicated, the signals received by receiver 22 may control the operation of the turnstile, to either allow a person to leave the area, or prevent his leaving, in accordance with the reception ofa control signal by receiver 22 from device I8.

FIG. 6 shows a variational device which may be utilized for indicating an attempt to remove from a store or other area an article 150, which may typically be an article of merchandise displayed for sale in the store. The device of FIG. 6 may be very similar to transponder device 18 of FIGS. I to 4, except for the deletion of key 19 and the contacts to be engaged thereby. The integrated circuit 26a of FIG. 6 may be otherwise identical with circuit 26 of FIG. 4, and may be formed on a silicon chip such as that illustrated at 31 in FIG. 3, and be completely encapsulated within an electrically insulative material 32a. The encapsulated unit is adapted to be attached in any suitable manner to the article of merchandise a or other article, as by provision of a layer of pressure sensitive adhesive 47 on one surface of the capsule, and/or by provision of a flange or tab 48 on the capsule, typically containing an opening 49 by which the capsule may be pinned or otherwise fastened to an article of clothing or other piece of merchandise to be protected.

When an unauthorized person attempts to remove the article 15a from the selling area or room, he must in leaving the room pass a transmitter such as that shown at in FIG. 1, a receiver 22, indicator 23, etc. Upon reception of the signal emitted by transmitter 20 the device 18a of FIG. 6 will transmit a response signal of doubled or other harmonic frequency serving to actuate the indicator 23 or other unit serving as an alarm for apprising an attendant of the attempted theft. When an article carrying one of the devices 18a is sold, a sales person may remove the transponder device 18a, or alternatively may merely bring the device near a highly powered transmitter represented diagrammatically at 50 in FIG. 6, in a manner such that the radio signal emitted by transmitter 50 will produce in the

coils

27a and 29a of the integrated circuit in device 180 a current so great as to purposely burn out or destroy one or more of the diodes 30 or other components of the integrated circuit, and thereby disable it in a manner such that it will not subsequently actuate the alarm system when the purchaser passes the transmitting equipment upon leaving the sales area.

The device 18a of FIG. 6, or other variations of the invention, may also be used on or as identification badges, to be worn or carried by persons in a manufacturing plant or the like, for indicating whether these persons are authorized to enter or leave a particular area policed by a transmitter, receiver, etc., as shown in FIG. I. In that case, the identification badge or the device 18a itself becomes the article whose movement between areas is either authorized or unauthorized, and is to be controlled by the monitoring equipment.

While certain specific embodiments of the present invention have been disclosed as typical, the invention is of course not limited to these particular forms, but rather is applicable broadly to all such variations as fall within the scope of the appended claims.

I. Apparatus for detecting an attempted unauthorized movement of an article between two areas, comprising means for transmitting a first radio signal at or near said areas, circuitry carried by said article responsive to said first signal and operable to transmit a second and different radio signal, means responsive to said second signal and operable to indicate whether an attempted movement of said article is authorized, and a control key device which is separable from said article and is adapted to alter the response of said circuitry to said first signal in a manner which may be sensed by said last mentioned means to indicate that a person having the key device is authorized to move the article.

2. Apparatus as recited in claim 1, in which said circuitry in a predetennined normal condition is responsive to said first signal to produce said second signal, said control key device being operable to disable the circuitry against transmission of said second signal.

3. Apparatus as recited in claim 1, in which said circuitry includes an antenna for receiving said first signal, a rectifier for producing said second signal from said first signal at a frequency which is a harmonic of the frequency of the first signal, and an antenna for emitting said second signal, said key device being movable to a predetermined position relative to said circuitry and operable to short circuit said circuitry in a relation preventing transmission of said second signal, there being means on said article defining a receptacle for removably retainingsaid key at said position.

4. Apparatus as recited in claim 1, in which said circuitry includes an antenna for receiving said first-signal, a rectifier for rectifying the received first signal to produce an output of doubled frequency, and a transmitting antenna for transmitting said second signal at said doubled frequency.

5. Apparatus as recited in claim 1, including holder means for removably receiving and holding said key device at a predetermined active position in which its presence has an effect on said second signal.

6. A device for detecting an attempted unauthorized movement of an article between two areas, comprising a structure to be carried by the article and having circuitry adapted to receive a first radio signal from a transmitter at or near said areas, and responsive to said first signal to produce a second and different radio signal for indicating by said secondsignal whether an attempted movement of the article is authorized, and a control key device which is separable from said structure and adapted to be carried by an authorized person and is adapted to alter the response of said circuitry to said first signal in a relation indicating that the person is authorized.

7. A device as recited in claim 6, in which said circuitry is a transponder circuit utilizing the received power of said first signal to produce said second signal.

8. A device as recited in claim 6, including holder means for removably receiving and holding said key device at a predetermined active position in which its presence has an efiect on said second signal.

9. A device as recited in claim 6, in which said circuitry includes antenna means for receiving said first signal, rectifier means for rectifying said first signal and producing said second signal at a frequency which is a harmonic of the frequency of the first signal, and antenna means for emitting said second signal, there being a socket for removably receiving said key device, said key device being operable when in said socket to disable said circuitry against production of said second signal.

10. The combination comprising an article which may be removed from a predetermined area, and a device carried by said article for indicating an attempted unauthorized removal of the article from said area, said device including circuitry adapted to receive a first radio signal from a transmitter at or near said area, and responsive to said first signal to produce a second and different radio signal for indicating by said second signal whether an attempted removal of the article is authorized, and a control key which is separable from said device and is adapted to alter the response of said circuitry to said first signal in a relation indicating that a person having said key is authorized.

11. The combination as recited in claim 10, in which said article is an article of baggage.

12. The method of detecting an attempted unauthorized movement of an article between two areas,comprising requiring said article to be carried past a detection station if it is moved between said areas, transmitting a radio signal to said article as it passes said station, providing the article with circuitry responsive to said transmitted signal and operable to transmit a second radio signal, monitoring said second signal as an indication of whether an unauthorized movement of the article is being attempted, applying a key to said circuitry if movement of said article is authorized, changing the condition. of said circuitry by use of said key, and detecting said change in condition of the circuitry through a change in said second signal.

13. Apparatus for detecting an attempted unauthorized movement of an article between two areas, comprising circuitry carried by said article and operable to transmit a radio signal which is to be monitored by a receiver and which indicates whether said movement of the article is authorized, and a key which is separable from said article and is adapted to alter the transmission of said radio signal in a manner which may be sensed by said receiver to indicate that a person having the key is authorized.

14. The method of detecting attempted unauthorized movement of any of a number of articles between two ares, comprising requiring said articles to be carried past a detection station upon such movement, monitoring radio signals received from circuitry carried by said articles as they are moved past said station, converting said circuitry of any article authorized for said movement to a condition different from that of any articles not authorized for said movement by means of keys carried by authorized persons and separable from said articles, and distinguishing between said authorized and unauthorized articles by differences in said monitored radio signals.

15. Apparatus for controlling movement of an article between two areas; comprising means to be located at or near said areas and operable to transmit a first radio signal to circuitry carried by said article; means for receiving a response signal from said circuitry and determining therefrom whether or not said movement of the article is authorized; a turnstile or other movement controlling structure between said areas; and

means controlling operation of said turnstile or other movement controlling structure in correspondence with changes in said response signal.

16. The method of detecting an attempted unauthorized movement of an article between two areas, comprising requiring said article to be carried past a detection station if it is moved between said areas, transmitting a radio signal to said articles as it passes said station, providing the article with circuitry responsive to said transmitted signal and operable to transmit a second radio signal, monitoring said second signal as an indication of whether an unauthorized movement of the article is being attempted, and applying to said circuitry a third radio signal intense enough to purposely destroy its capacity to produce said second signal, if said movement of the article is to be authorized.

Claims

1. Apparatus for detecting an attempted unauthorized movement of an article between two areas, comprising means for transmitting a first radio signal at or near said areas, circuitry carried by said article responsive to said first signal and operable to transmit a second and different radio signal, means responsive to said second signal and operable to indicate whether an attempted movement of said article is authorized, and a control key device which is separable from said article and is adapted to alter the response of said circuitry to said first signal in a manner which may be sensed by said last mentioned means to indicate that a person having the key device is authorized to move the article.

2. Apparatus as recited in claim 1, in which said circuitry in a predetermined normal condition is responsive to said first signal to produce said second signal, said control key device being operable to disable the circuitry against transmission of said second signal.

3. Apparatus as recited in claim 1, in which said circuitry includes an antenna for receiving said first signal, a rectifier for producing said second signal from said first signal at a frequency which is a harmonic of the frequency of the first signal, and an antenna for emitting said second signal, said key device being movable to a predetermined position relative to said circuitry and operable to short circuit said circuitry in a relation preventing transmission of said second signal, there being means on said article defining a receptacle for removably retaining said key at said position.

4. Apparatus as recited in claim 1, in which said circuitry includes an antenna for receiving said first signal, a rectifier for rectifying the received first signal to produce an output of doubled frequency, and a transmitting antenna for transmitting said second signal at said doubled frequency.

6. A device for detecting an attempted unauthorized movement of an article between two areas, comprising a structure to be carried by the article and having circuitry adapted to receive a first radio signal from a transmitter at or near said areas, and responsive to said first signal to produce a second and different radio signal for indicating by said second signal whether an attempted movement of the article is authorized, and a control key device which is separable from said structure and adapted to be carried by an authorized person and is adapted to alter the response of said circuitry to said first signal in a relation indicating that the person is authorized.

8. A device as recited in claim 6, including holder means for removably receiving and holding saId key device at a predetermined active position in which its presence has an effect on said second signal.

12. The method of detecting an attempted unauthorized movement of an article between two areas, comprising requiring said article to be carried past a detection station if it is moved between said areas, transmitting a radio signal to said article as it passes said station, providing the article with circuitry responsive to said transmitted signal and operable to transmit a second radio signal, monitoring said second signal as an indication of whether an unauthorized movement of the article is being attempted, applying a key to said circuitry if movement of said article is authorized, changing the condition of said circuitry by use of said key, and detecting said change in condition of the circuitry through a change in said second signal.

15. Apparatus for controlling movement of an article between two areas; comprising means to be located at or near said areas and operable to transmit a first radio signal to circuitry carried by said article; means for receiving a response signal from said circuitry and determining therefrom whether or not said movement of the article is authorized; a turnstile or other movement controlling structure between said areas; and means controlling operation of said turnstile or other movement controlling structure in correspondence with changes in said response signal.