Abstract:
A portable container for one or more articles each tagged with a respective Radio Frequency Identification (RFID) transponder, the container comprising a detector device for detecting removal and/or placement of RFID-tagged articles in the container; a power supply for supplying electrical power to the detector device; an activation means operable to cause the detector device to detect a reference list of RFID-tagged articles located in the container; a verification means operable by movement of the container to cause the detector device to detect RFID-tagged articles located in the container and to signal deviation from the reference list; and a signal means for transmitting signals from the detector device to a user. The detector device may transmit an article absent signal and/or an unknown article signal. The detector device may comprise an external antenna configured to detect RFID-tagged articles outside the container.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from PCT Application No. PCT/EP2014/062702, international filing date of Jun. 17, 2014, which claims priority from EP 13175285.9 filed Jul. 5, 2013 the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a portable container with a detector device for detecting removal and/or placement of articles in the container and a method of detecting removal and/or placement of articles in a portable container. 
       BACKGROUND OF THE INVENTION 
       [0003]    Although the following description refers to a tool bag it will be appreciated by the person skilled in the art that the apparatus for detecting the presence of articles in a container can be used in any portable container, for example, tool cabinets, tool cupboards, tool boxes, backpacks, and the like, and it is not limited to tool bags. 
         [0004]    The use of tool bags to contain tools and accessories for tools is well known. When an operator is performing a job on site tools and other articles are routinely removed from a tool bag to perform the job but they may not be replaced in the tool bag after the job is finished. The tools and other articles may remain at the job site and/or become lost. This is a problem because many tools are expensive to replace. It is also problem in industrial environments where mislaid tools or other articles risk causing damage to machinery. Many industrial environments, for example, aerospace, railway, shipbuilding, nuclear, automobile, or petrochemical sectors, are particularly sensitive to what is referred to as ‘foreign object damage’ to their machinery. Naturally, these sectors are particularly interested in foreign object exclusion solutions. 
         [0005]    German utility model No. DE 202 07 572 U1 discloses a tool box carried by craftspeople to jobs outside their own workshop. The tools do not have a space permanently allocated to them in the tool box. Instead, the tools lie loosely in disorder in the tool box. Whilst this may be an efficient use of space within the tool box, it is not easy to visually inspect which tools are in the tool box. So, each tool comprises a smart label like that known in the retail industry. The tool box comprises an interrogation device. Upon activation, the interrogation device determines the completeness or incompleteness of the tools in the tool box. The interrogation device may be programmed to determine which tools are missing and indicate them on a display. 
         [0006]    A smart label is a type of Radio Frequency Identification (RFID) transponder. An RFID transponder is an electronic identification device that may be used to uniquely identify and track various articles. In practice, an RFID transponder is attached to an article, and a RFID reader like the interrogation device of DE 202 07 572 U1 senses the presence and identifying information associated with the RFID transponder. The RFID transponder may be active, semi-active, or passive and may or may not include storage memory. The RFID transponder contains information, for example the type and serial number of the tool to which it is tagged. 
         [0007]    United Kingdom patent publication No. GB 2 451 957 A discloses a tool box equipped with a handle, a detection means, an activation button, an alarm and an LCD display screen. In use, the tool box contains a number of tools tagged with RFID transponders which the tool box is intended to transport from site to site. The RFID transponders are registered to their corresponding tools on an external computer and the registration data is downloaded to the tool box. The detection means is configured to detect if any tools are missing from the tool box using the registration data. When a user arrives at site, the activation button is pressed, the detection means scans the contents of the tool box and records the RFID-tagged tools into a first inventory stored in a memory of the detection means. Once the job is complete, the user gathers the RFID-tagged tools and replaces them in the tool box. The activation button is pressed again, the detection means scans the contents of the tool box and compiles a second inventory for comparison with the first inventory. If the detection means identifies that any RFID-tagged tools are missing that were present the first time the activation button was pressed, the alarm sounds to alert the user. The name of the missing tool and its RFID transponder number are displayed to the user on the LCD screen. GB 2 451 957 A discloses a variant tool box where the detection means continually scans the presence of RFID-tagged tools in the tool box. The variant detection means alerts the user if any RFID-tools are missing when the tool box lid is closed. 
         [0008]    In a busy working environment, users of the aforementioned tool boxes may not have time, or may forget, to activate the detection means on a regular basis. A missing RFID-tagged tool may not be noticed until a long time after it has been lost. Even if the missing tool is identified by the detection means this is of little use if the missing tool cannot be physically found because the user cannot recall when and where it was last used. Thus, inattention to regular activation of the detection means may result in time being wasted while the user searches for a missing tool. The missing tool may not eventually be found. On the other hand, continual cyclical activation of the detection means either requires more electrical power and frequent recharging of a portable electrical power source or it requires connection to an external power source. Either option would inhibit mobility. 
       BACKGROUND OF THE INVENTION 
       [0009]    It is an aim of the present invention to overcome or at least mitigate the aforementioned problems. In a first aspect of the invention there is provided a portable container for one or more articles each tagged with a respective RFID transponder, the container having at least one opening into the container and a detector device for detecting removal and/or placement of RFID-tagged articles in the container, wherein the container comprises: a power supply for supplying electrical power to the detector device, an activation means in communication with the detector device, wherein the activation means is operable to cause the detector device to detect a reference list of RFID-tagged articles located in the container; a verification means in communication with the detector device, wherein the verification means is operable by movement of the container to cause the detector device to detect RFID-tagged articles located in the container and to signal deviation from the reference list; and a signal means in communication with the detector device for transmitting signals from the detector device to a user. The activation means enables a user to record a reference list of RFID-tagged articles initially selected to perform a job. The user transports the container to the work site and begins the job. At the end of the job, or working day, the user returns to the source of the RFID-tagged articles. The involves moving the container which automatically operates the verification means and causes the detector device to detect and compare the RFID-tagged articles actually in the container with the reference list. If there are too many, or too few, articles then the user has taken someone else&#39;s property or forgotten their own articles. The user is automatically alerted by the signal means to any deviation between what actually is, and what should be, in the container before the user has left the work site. The signal means may transmit any signal that attracts the attention of the user, for example, an information display signal, an optical signal, an audible signal or tactile signal such as vibration. The signal may vary according to the type information to be transmitted. Advantageously, the user is alerted promptly by the signal means thus making it easier to search for missing articles or return someone else&#39;s articles before the situation evolves and the memory fades. Inattention on the part of the user cannot neglect to operate the detector device; this occurs automatically when the container is moved. The detector device is only operated by the verification means when the container moves and not continuously. This economises on electrical power consumption by the detector device. 
         [0010]    Preferably, the detector device is configured to signal an article absent signal upon detection of absence of a RFID-tagged article on the reference list and the detector device is configured to signal an unknown article signal upon detection of a RFID-tagged article not on the reference list. Thus, the user can tell whether there are too many, or too few, articles in the container and react accordingly. 
         [0011]    The detector device may be lockable against detection of the reference list. Locking of the detector device prevents accidental modification to the reference list after it has been recorded by the user. Thus, the user can be sure that any deviation signal relates to deviation from the original reference list. A key is needed to enable modification to the reference list. This may be required, for example, at the end of the working day when the user may wish to empty the container of RFID-tagged tools and reset the reference list to zero in preparation for another working day. 
         [0012]    Preferably, the detector device is configured to signal an initialisation signal upon location in the container of a RFID-tagged key configured to permit detection of the reference list. The initialisation signal confirms that the reference list has been established in the presence of the RFID-tagged key. The user obtains the RFID-tagged key to unlock the detector device. 
         [0013]    The verification means may comprise an accelerometer. An accelerometer experiences acceleration associated with movement of weight. This is a simple means of detecting movement of the container which does not rely on interaction with anything outside the container. 
         [0014]    The signal means may comprise at least one LED. LEDs are reliable means of providing an optical signal to a user. Advantageously, LEDs are more efficient than, for example, conventional filament lamps. This may help to economise electrical power consumption by the detector device. 
         [0015]    Preferably, the or each LED is a multicoloured LED. This enables the detector device to provide different colour optical signals according to the nature of the signal transmitted. This may help to clarify the meaning of the various signals when they are transmitted optically to the user. 
         [0016]    The container may comprise a translucent body optically coupled to the or each LED. The translucent body helps to diffuse light from the or each LED to provide a glowing optical signal. 
         [0017]    If the container comprises a handle then preferably the translucent body forms at least part of the handle. The handle is an important part of the container which provides prominent a place to transmit optical signals to a user. 
         [0018]    The signal means may comprise a display configured to display the number and/or identify of RFID-tagged articles detected by the detector device in the container. A display can provide detailed information on the RFID-tagged articles. 
         [0019]    Preferably, the display is configured to display the article absent signal, wherein the article absent signal comprises number and/or identify of absent RFID-tagged articles. Thus, the user knows which particular RFID-tagged article is missing outside the container and the user need not search amongst the articles inside the container. This may save time, especially if the missing article is visible to the user. 
         [0020]    The detector device may comprise a transponder reader device comprising an antenna reader and at least one internal antenna in communication with the antenna reader, wherein the or each internal antenna is configured to detect only RFID-tagged articles in the container. This may avoid false detection of RFID-tagged articles outside the container which could fool the user into thinking that the complete reference list of articles is inside the container when this is not true. 
         [0021]    The detector device may comprise an external antenna in selectable communication with the antenna reader, wherein the external antenna is configured to detect RFID-tagged articles outside the container. Detection of RFID-tagged articles with the external antenna may occur upon selection by the user. Preferably, the external antenna is configured to detect only RFID-tagged articles on the initial reference list. This filters unwanted detection of articles that the user is not searching for and may save the user time and effort. 
         [0022]    The external antenna may be portable in relation to the container. This may improve the range of the antenna. 
         [0023]    The detector device may comprise a data processing device having a central processing unit and a memory for recording at least the reference list. 
         [0024]    The container may comprise one of a tool cabinet, a tool cupboard, a tool box, or a tool bag. The container of the invention may be any one of those commonly used in the industrial or workshop environment. The container may be for containment of one or more RFID-tagged tools. Tools can be expensive and it is beneficial to provide a device for tracking and retaining tools lest they become lost or misplaced inside machinery where they can cause inestimable damage. 
         [0025]    In a second aspect of the invention, there is provided a method of detecting removal and/or placement of articles in a container, wherein each article is tagged with a respective RFID transponder, wherein the container has at least one opening into the container, a detector device for detecting removal and/or placement of RFID-tagged articles in the container, a power supply for supplying electrical power to the detector device, an activation means in communication with the detector device, a verification means in communication with the detector device, and a signal means in communication with the detector device for transmitting signals from the detector device to a user, and wherein the method comprises the steps of: (a) operating the activation means to cause the detector device to detect a reference list of RFID-tagged articles located in the container and optionally to detect a RFID-tagged key configured to permit detection of the reference list; and (b) operating the verification means by movement of the container to cause the detector device to detect RFID-tagged articles located in the container and to signal detection of deviation from the reference list. The second aspect or the invention provides substantially the same advantages as the first aspect. The optional additional feature may reassure the user that any deviation signal relates to deviation from the original reference list established in the presence of the RFID-tagged key. Accidental modification to the reference list is not possible; the user must obtain the RFID-tagged key to unlock the detector device. 
         [0026]    In an alternative aspect of the invention, there is provided a portable container for one or more articles each tagged with a respective RFID transponder, the container having at least one opening into the container and a detector device for detecting removal and/or placement of RFID-tagged articles in the container, wherein the container comprises: a power supply for supplying electrical power to the detector device; an activation means in communication with the detector device, wherein the activation means is operable to cause the detector device to detect RFID-tagged articles located in the container; a signal means in communication with the detector device for transmitting signals from the detector device relating to RFID-tagged articles located in the container, wherein the signal means comprises an optical signal generator; and a translucent body optically coupled to the optical signal generator. The optical signal generator may be any means of producing a light, like, for example, a filament lamp or an LED. Preferably, the container comprises a handle and wherein the translucent body forms at least part of the handle. Preferably, the handle is elongate and the translucent body extends along the majority of the axis of elongation of the handle. Preferably, the translucent body surround the axis of elongation of the handle. Preferably, the optical signal generator comprises at least one LED. Preferably, the or each LED is a multicoloured LED. 
         [0027]    Preferably, the activation means is operable to cause the detector device to detect a reference list of RFID-tagged articles located in the container, wherein the portable container comprises a verification means in communication with the detector device, and wherein the verification means is operable by movement of the container to cause the detector device to detect RFID-tagged articles located in the container and to signal deviation from the reference list. Preferably, the detector device is configured to signal an article absent signal upon detection of absence of a RFID-tagged article on the reference list and the detector device is configured to signal an unknown article signal upon detection of a RFID-tagged article not on the reference list. Preferably, the detector device is lockable against detection of the reference list. Preferably, the detector device is configured to signal an initialisation signal upon location in the container of a RFID-tagged key configured to permit detection of the reference list. Preferably, the verification means comprises an accelerometer. Preferably, the signal means comprises a display configured to display the number and/or identify of RFID-tagged articles detected by the detector device in the container. Preferably, the display is configured to display the article absent signal and wherein the article absent signal comprises the number and/or identify of absent RFID-tagged articles. Preferably, the detector device comprises a transponder reader device comprising an antenna reader and at least one internal antenna in communication with the antenna reader and wherein the or each internal antenna is configured to detect only RFID-tagged articles in the container. Preferably, the detector device comprises an external antenna in selectable communication with the antenna reader and wherein the external antenna is configured to detect RFID-tagged articles outside the container. Preferably, the external antenna is configured to detect only RFID-tagged articles on the initial reference list. Preferably, the external antenna is portable in relation to the container. Preferably, the detector device comprises a data processing device having a central processing unit and a memory for recording at least the reference list. Preferably, the container comprises one of a tool cabinet, a tool cupboard, a tool box, or a tool bag. Preferably, the container is for containment of one or more RFID-tagged tools. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    Embodiments and advantages of the invention will be understood by reference to the following description which is given by way of example and in association with the accompanying drawings of which: 
           [0029]      FIG. 1  shows a side elevation view of a container in accordance with an embodiment of the invention; 
           [0030]      FIG. 2  shows a top view of the container of  FIG. 1 ; 
           [0031]      FIG. 3  shows a tool for placement in the container of  FIG. 1 ; 
           [0032]      FIG. 4  shows a cross-section view IV-IV of the container of  FIG. 1 ; 
           [0033]      FIG. 5  shows a block diagram of an electrical circuit of the container of  FIG. 1 ; and 
           [0034]      FIG. 6  shows a cross-section view of detail VI of a handle of the container of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Referring to  FIGS. 1 and 2 , there is shown a container in the form of a tool bag  2 . The tool bag  2  comprises a handle  4  and a tool bay  6 . The handle  4  is connected to a metal frame which forms the shape of the tool bag  2 . The tool bay  6  comprises a pair of opposing side walls  8   a ,  8   b,  a pair of opposing end walls  10   a ,  10   b  and a base  12 . The side walls  8   a ,  8   b  and end wall  10   a ,  10   b  are made of a flexible and durable material which is clad about the frame of the tool bag  2 . The base  12  is made of a rigid plastic material and is fixed to the bottom of the fame. The base  12  comprises an internal cavity  14  the use of which is explained in more detail below. Although not shown, the tool bag  2  may comprise a lid made of the same material as the side walls  8   a ,  8   b  and end walls  10   a ,  10   b  for locating over the handle  4  and enclosing the tool bay  6 . 
         [0036]    The tool bag  2  is intended to be used as a container for transporting tools  16  each of which is tagged with its own RFID transponder  18  programmed with a unique identification signature. The RFID-tagged tools  16  are loosely located in the tool bay  6  in no particular order such that it is difficult to know by visual inspection exactly which tools  16  are in the tool bay  6  at any one time. The tool bay  6  is shaped to avoid spillage of RFID-tagged tools  16  during transportation. An example RFID-tagged tool  16  is shown in  FIG. 3 . 
         [0037]    Referring to  FIGS. 4 to 6 , the tool bag  2  is equipped with an electrical circuit  20  for detecting and identifying the number of RFID-tagged tools  16  located in the tool bay  6 , detecting if any known RFID-tagged tools  16  are missing from the tool bag  2  once a job is complete, detecting if any unknown RFID-tagged tools  16  are in the tool bag  16  once a job is complete, alerting the user if there is a discrepancy in the number of RFID-tagged tools  16 , and locating missing RFID-tagged tools  16 . The electrical circuit  20  performs these tasks autonomously and without being networked. 
         [0038]    The electrical circuit  20  has a detector device comprising a transponder reader device  21  and a data processing device  22 . The data processing device  22  has a central processing unit (CPU)  23  and a memory  24 . The data processing device  23  is in communication with an antenna reader  25  of the transponder reader device  21  via a serial link  26 . The data processing device  22  and the antenna reader  25  are housed within the cavity  10  of the base  12  for protection from any RFID-tagged tools  16  contained within the tool bay  6 . The electrical circuit  20  comprises two internal antennas  28   a ,  28   b,  a battery pack  30  and an initialisation button  32  which are directly coupled to the antenna reader  25  except for the battery pack  30  which is coupled to the antenna reader  25  via an on/off button  36 . Optionally, the electrical circuit  20  may comprise an external antenna  34  coupled to the antenna reader  25 . The external antenna  34 , if present, the internal antennas  28   a ,  28   b,  and the antenna reader  25  perform the role of the transponder reader device  21  which tracks and identifies RFID-tagged tools  16 , as is explained in more detail below. The electrical circuit  20  further comprises rows of multicoloured light emitting diodes (LEDs)  38 , a movement detector  40  and an LCD display  42  which are directly coupled to the data processing device  22 . The internal antennas  28   a ,  28   b,  the battery pack  30  and the movement detector  40  are housed within the cavity  14  of the base  12 . 
         [0039]    The middle of the handle  4  is formed by an elongate tubular sheath  44  spanning short metal parts  4   a ,  4   b  of the handle  4  integrally connected to opposite ends of the metal frame. A first end of the sheath  44  is connected by a gland  45   a  to the first short metal part  4   a  of the handle  4 . A second end of the sheath  44  opposite to the first end of the sheath is connected by a gland  45   b  to the second short metal part  4   a  of the handle  4  opposite to the first short metal part  4   b.  The sheath  44  is made of any rigid substantially transparent material which is strong enough to support a tool bag  2  full of RFID-tagged tools  16 , like, for example, polycarbonate, polyamide or polymethyl methacrylate plastic materials, or the like. The sheath is sized to be grasped by a user&#39;s hand. The initialisation button  32 , the on/off button  36  and the LCD display  42  are seated in a side of the sheath  44  accessible to a user. The sheath  44  comprises a tubular translucent liner  44   a  arranged about its interior surface along the majority of the sheath&#39;s axis  44   b  of elongation. The LEDs  38  are arranged in a band, or line, inside the sheath  44  and its translucent liner  44   a.  The translucent property of the sheath&#39;s liner  44   a  helps to diffuse light from the LEDs  38  to make them glow with enhanced visibility to the user. The interior of the sheath  44  is sealed from the external environment by the glands  45   a ,  45   b.    
         [0040]    Optionally, the data processing device  22 , the antenna reader  25 , the internal antennas  28   a ,  28   b,  the battery pack  30  and the movement detector  40  may be housed elsewhere in the tool bag  2 , for example in a pocket in a side wall  8   a ,  8   b  or an end wall  10   a ,  10   b . This is provided that there is suitable protection from RFID-tagged tools  16  contained within the tool bay  6 . 
         [0041]    The battery pack  30  comprises rechargeable cells which supply the electrical circuit  20 , via the antenna reader  25 , with an electrical power supply of approximately 24V and 2.5 Amperes. The actual voltage and current of the power supply can vary according to manufacturer preferences without changing the character of the invention. Electrical current from the battery pack  30  is connected or disconnected to the antenna reader  25  by the on/off button  36  which is operable by the user. 
         [0042]    The initialisation button  32  is operable by the user to initiate counting and identification of any RFID-tagged tools  16  located in the tool bay  6 . The multicoloured LEDs  38  are illuminated different colours by the data processing device  22  to convey different optical signals to a user. The movement detector  40  comprises an accelerometer which is configured to detect movement of the tool bag  2 . When the movement detector  40  detects movement of the tool bag  2  it transmits a movement detection signal to the data processing device  22 . The internal antennas  28   a ,  28   b  have a range which is limited to detect RFID-tagged tools  16  located in the tool bay  6  only. This is to prevent the internal antennas  28   a ,  28   b  from making false detections of RFID-tagged tools  16  located outside the tool bay  6 . 
         [0043]    If present, the external antenna  34  is housed in a hand-holdable scanner case  46  which is detachably hooked to the of the tool bag  2 . The external antenna  34  is coupled to the antenna reader  25  via a coiled wire  48  and a scanner activation button  50 , as is explained in more detail below. 
         [0044]    The antenna reader  25  is configured to read information from the internal antennas  28   a ,  28   b  on RFID-tagged tools  16  in the tool bay  6  and to read information from the external antenna  34  on RFID-tagged tools outside the tool bag  2 . This information is supplied from the transponder reader device to the data processing device  22  which identifies the RFID-tagged tools  16  and records them in the memory  24 . The LCD display  42  communicates information from the data processing device  22  to the user, for example the number of RFID-tagged tools  16  in the tool bay  6  and/or the identity of a missing RFID-tagged tool  16 . 
         [0045]    Use of the tool bag  2  shall now be described in more detail. 
         [0046]    Initially, a user takes the tool bag  2  to a storage facility, for example a storeroom. The user operates the on-off button  36  to supply the electrical circuit  20  with electrical current and waits a few seconds for the electrical circuit  20  to be ready for use. The data processing unit  22  illuminates the LEDs  38  blue for a few seconds when the electrical circuit  20  is ready for use. 
         [0047]    The user fills the tool bay  6  with RFID-tagged tools  16  required to perform a particular job. The storage facility is equipped with a key (not shown) with an RFID transponder programmed with data which authorises initialisation cycles of the electrical circuit  20 . The user places the RFID-tagged key in the tool bay  6  and depresses the initialisation button  32 . The transponder reader device  21 , via the internal antennas  28   a ,  28   b,  detects the presence of the RFID-tagged key and an initialisation cycle begins. Note that without the presence of the RFID-tagged key an initialisation cycle is not authorised, in other words the transponder reader device  21  is locked against performing an initialisation cycle. When the transponder reader is unlocked by presence of the RFID-tagged key, the transponder reader device  21  counts and identifies RFID-tagged tools  16  located in the tool bay  6  and records an initial reference list of RFID-tagged tools  16  in the memory  24  of the data processing device  22 . When the initialisation cycle is complete, the electrical circuit  20  illuminates the LEDs  38  green for a few seconds and indicates the number of the RFID-tagged tools  16  located in the tool bay  6  on the display  42 . The green LEDs  38  reassure the user that the electrical circuit  20  has counted, identified and memorised the reference list of ‘known’ RFID-tagged tools  16  and that the tool bag  2  is ready to be transported from the storage facility. Optionally, the green LEDs  38  may be supplemented by an audible alarm. 
         [0048]    Next, the user transports the tool bag  2  to a job site, positions the tool bag  2  near or at the job site and removes one or more RFID-tagged tools  16  required to do a job from the tool bay  6 . RFID-tagged tools  16  can enter and exit the tool bay  6  without provoking a reaction from the electrical circuit  20  because it is dormant. This helps to reduce power consumption and extend the life of the battery pack  30  between recharges. 
         [0049]    At the end of a job the user will want to move the tool bag  2  to another job site or return to the storage facility. The movement detector  40  detects movement of the tool bag  2  and the data processing device  22  automatically initiates a verification cycle of RFID-tagged tools  16  located in the tool bay  6 . During the verification cycle, the transponder reader device  21 , using the internal antennas  28   a,    28   b,  detects the presence of RFID-tagged tools  16  in the tool bay  6 . The data processing device  22  compares the RFID-tagged tools  16  actually located in the tool bay  6  with the reference list of ‘known’ RFID-tagged tools  16 . 
         [0050]    If the verification cycle reveals that the same RFID-tagged tools  16  are in the tool bay  6  as are on the reference list, the electrical circuit  20  illuminates the LEDs  38  green for a few seconds to reassure the user that no RFID-tagged tools  16  are absent. Optionally, the green LEDs  38  may be supplemented by an audible alarm. 
         [0051]    If the verification cycle reveals that one or more ‘unknown’ RFID-tagged tools  16  are in the tool bay  6  that are not on the reference list, the electrical circuit  20  flashes the LEDs  38  red for a few seconds to warn the user. Optionally, the flashing red LEDs  38  may be supplemented by an audible alarm which is distinct from the audible alarm sounded when the LEDs  38  are illuminated green. This prevents the user from accidentally taking a RFID-tagged tool  16  that does not belong to the user. 
         [0052]    If the verification cycle reveals that one or more RFID-tagged tools  16  on the reference list are absent from the tool bay  6  the electrical circuit  20  illuminates the LEDs  38  red for a few seconds to warn the user. Optionally, the illuminated red LEDs  38  may be supplemented by an audible alarm which is distinct from the audible alarm sounded when the LEDs  38  are illuminated green or when the LEDs  38  flash red. This avoids RFID-tagged tools  16  being left behind at the job and possibly remaining inside machinery where they can cause inestimable damage. The display  42  indicates the number and identity of absent RFID-tagged tools  16  so that the user knows what to search for. 
         [0053]    If present, the scanner case  46  may be unhooked from the tool bag  2  by a user in search of stray RFID-tagged tools  16  outside the tool bay  6 . The coiled wire  48  enables the scanner case  46  to be manoeuvred about the exterior of the tool bag  2 . The user knows which RFID-tagged tools  16  to search for from the information on the display  42 . The user depresses the scanner activation button  50  to activate the external antenna  34  of the transponder reader device  21 . While the external antenna  34  is active the internal antennas  28   a ,  28   b  are inactive. When the external antenna  34  is active the electrical circuit  20  only searches for those RFID-tagged tools  16  that were identified as absent at the end of the verification cycle. The electrical circuit  20  confirms if one such absent RFID-tagged tool  16  is found by illuminating the LEDs  38  green. The user returns the found RFID-tagged tool  16  to the tool bay  6 . The search for absent RFID-tagged tools  16  should normally continue until all are found. When all the absent RFID-tagged have been found and returned to the tool bay  6 , the user releases the scanner activation button  50  and the external antenna  34  is automatically deactivated. Now the user can transport the tool bag  2  to another job site or return it to the storage facility. The movement detector  40  detects movement of the tool bag  2  and the data processing device  22  initiates another verification cycle of RFID-tagged tools  16  located in the tool bay  6 . The new verification cycle should confirm that the same RFID-tagged tools  16  are in the tool bay  6  as are on the reference list. If so, the electrical circuit  20  will illuminate the LEDs  38  green for a few seconds to reassure the user that no RFID-tagged tools  16  are absent. If not, and the new verification cycle discovers that one or more RFID-tagged tools  16  on the reference list are still absent from the tool bay  6 , the electrical circuit  20  illuminates the LEDs  38  red for a few seconds to warn the user. The user continues to search for missing RFID-tagged tools  16 , preferably with the help of the external antenna  34 . 
         [0054]    Ultimately, the user will transport the tool bag  2  to the storage facility, put it down and empty the RFID-tagged tools  16  from the tool bay  6 . The user places the RFID-tagged key in the tool bay  6  and depresses the initialisation button  32 . The transponder reader device  21 , via the internal antennas  28   a,    28   b,  detects the presence of the RFID-tagged key so that a fresh initialisation cycle can begin. The electrical circuit  20  counts and identifies what should be zero RFID-tagged tools  16  in the tool bay  6 . The reference list of RFID-tagged tools  16  recorded in the memory  24  is reset to zero. The electrical circuit  20  illuminates the LEDs  38  red for a few seconds to inform the user. The user operates the on-off button  36  to cut the supply of electrical current to the electrical circuit  20  and deactivate it. Thus, the tool bag  6  can be used with any number or combination of RFID-tagged tools  16  because the electrical circuit  20  is capable of re-counting and re-identifying the RFID-tagged tools  16  in the tool bay  6  to refresh the reference list recorded in the memory  24 . 
         [0055]    The battery pack  30  can be connected to a battery recharger (not shown) via battery socket  52  for recharging its empty cells as and when required. Battery charging is only possible when the electrical current from the battery pack  30  is disconnected by the on/off button  36 . 
         [0056]    The electrical circuit  20  can be fitted, or retro-fitted, to any portable container, for example tool cabinets, tool cupboards, tool boxes, backpacks, and the like, and not just the tool bag  2  described above. 
         [0057]    The actual colours of the LEDs  38  chosen to indicate signals to the user can be varied according to manufacturer preferences without changing the character of the invention.