Abstract:
A biometric key ( 10 ) having a body or housing ( 11 ) incorporating a biometric sensor ( 17 ) uses a plurality of contacts ( 19, 20, 21 ) enabling the key to gain access to a facility. There is also provided a receptor ( 25 ) for receiving the biometric key ( 10 ), wherein the biometric key ( 10 ) and receptor ( 24 ) have contacts ( 19, 20, 21 ) and mating contacts ( 30, 31, 32 ), respectively, for communicating. The biometric key ( 10 ) can communicate biometric data acquired from a key operator to the receptor ( 25 ). The biometric key ( 10 ) can communicate with the receptor ( 25 ) when received in a first orientation and also when received in a second orientation where the contacts ( 19, 20, 21 ) are inverted from the first orientation.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to a biometric security assembly for providing access to a facility.  
       BACKGROUND TO THE INVENTION  
       [0002]     Security systems are relied upon to secure environments and possessions such as cars, homes, businesses and prisons. Keys and locks are integral to most security systems but unfortunately, keys can be lost or duplicated and a security system can then be breached.  
         [0003]     Electronic or electrically activated security assemblies often require a battery for their power source and this can be disadvantageous in that batteries require constant replacement and this increases maintenance costs.  
         [0004]     To overcome the disadvantages of conventional lock and key systems as described above a conventional biometric security assembly has been developed that reads biometric data from an operator in order to verify the operator&#39;s identity.  
         [0005]     A biometric security assembly which includes a biometric key and lock for engagement with the key is described in Australian Patent 757159. The biometric key is provided with a sensor as well as one or more electrical contacts that touch a mating contact(s) of the lock in use so that a signal representing a biocode of data in regard to the user of the biometric key is sent to processing means incorporated in the lock. Upon matching of the signal with an authorised biocode in a database associated with the processing means the lock may be opened to provide access to a facility.  
         [0006]     While the abovementioned conventional biometric security assembly is satisfactory in use it is possible for this security assembly and other conventional security systems which utilise an electrical connection between the lock and the key to have problems in maintaining polarity of the electrical connection and with shorting of the electrical contacts to ground or each other while the key is being inserted in the lock. This problem has been addressed to some extent for example in U.S. Pat. No. 5,337,588 by allowing insertion of the key in only one orientation which limits its utility and through elaborate electromechanical means to ensure that the contacts do not short out, which increases the cost of manufacture.  
       OBJECT OF THE INVENTION  
       [0007]     It is therefore an object of the invention to overcome or reduce one or more problems associated with the prior art.  
       SUMMARY OF THE INVENTION  
       [0008]     The invention therefore provides a biometric key comprising a housing and a biometric sensor, a key circuit, and a plurality of electrical contacts connected to the housing wherein: 
        the key circuit incorporates a power supply circuit and a communications circuit;     at least two of the plurality of contacts are in electrical communication with the power supply circuit;     the communications circuit is in electrical communication with at least two of the plurality of contacts; and     at least two of the plurality of contacts can transmit and receive data, enabling the key to be received in a receptor in either of two configurations to provide access to a facility.        
 
         [0013]     Preferably, the sensor reads biometric data from a key operator.  
         [0014]     Preferably, at least two of the plurality of contacts are attached to diode circuits, where a first contact is connected to an anode of a first diode and to a cathode of a second diode, and a power supply is connected to a cathode of the first diode and the communications circuit is connected to an anode of the second diode.  
         [0015]     Preferably, the key incorporates a microprocessor.  
         [0016]     Preferably, the key has three contacts.  
         [0017]     Preferably, the communications circuit comprises an arrangement of a plurality of 2-input nand gates and a switch, wherein communication data is electrically communicated to both inputs of a first nand gate, an output of the first nand gate is electrically connected to an input of a second nand gate, both inputs of a third nand gate are electrically connected to a second input of the second nand gate, the output of the second nand gate provides a received data signal and a transmitted data signal is provided to both inputs of the third nand gate.  
         [0018]     Preferably, the receptor has a plurality of mating contacts.  
         [0019]     Preferably, the receptor has three mating contacts.  
         [0020]     Preferably, both the contacts of the key and the mating contacts of the receptor can transmit and receive data.  
         [0021]     Preferably, the receptor incorporates a receptor circuit that incorporates a power supply and a communications circuit.  
         [0022]     Preferably, the receptor incorporates a microprocessor.  
         [0023]     Preferably, the receptor incorporates a first resistor such that the resistor limits the power supply to supply only power levels that will not damage the receptor circuit or the key circuit.  
         [0024]     Preferably, the receptor incorporates a second resistor such that the resistor provides short circuit protection for the key circuit and/or the receptor circuit.  
         [0025]     Preferably, the communications circuit comprises an arrangement of a plurality of 2-input nand gates and a switch, wherein communication data is electrically communicated to both inputs of a first nand gate, an output of the first nand gate is electrically connected to an input of a second nand gate, both inputs of a third nand gate are electrically connected to a second input of the second nand gate, the output of the second nand gate provides a received data signal and a transmitted data signal is provided to both inputs of the third nand gate.  
         [0026]     In another form, the invention resides in a method for repeatedly opening a lock that prevents access to a facility, which method includes the steps of: 
        (i) inserting a biometric key comprising a biometric sensor into a receptor in a first configuration such that a plurality of key contacts are electrically connected to mating receptor contacts;     (ii) communicating data relating to the identity of a key operator from the sensor to the receptor via the key;     (iii) opening the lock a first time upon verification of the identity of the key operator;     (iv) inserting the biometric key comprising the biometric sensor into the receptor in a second configuration such that the plurality of key contacts are inverted from the first configuration and are electrically connected to the mating receptor contacts;     (v) communicating data relating to the identity of the key operator from the sensor to the receptor via the key; and     (vi) opening the lock a second time upon verification of the identity of the operator of the biometric key.       
 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]     Preferred embodiments of the invention are shown in the attached drawings wherein:  
         [0034]     FIGS.  1  to  4  show a side, top, plan, end and perspective view of the biometric key of the invention;  
         [0035]     FIGS.  5  to  7  are a perspective, side and top plan view of the door controller receptor of the invention;  
         [0036]      FIGS. 8 and 9  show a perspective view and a partial sectional view of the key and the door controller prior to engagement with each other;  
         [0037]      FIG. 10  is a view of the circuit in regard to both the biometric key of FIGS.  1  to  4  and the door controller receptor of FIGS.  5  to  7 ;  
         [0038]      FIGS. 11 and 12  show front and back views, respectively, of a second embodiment of the biometric key of the invention; and  
         [0039]      FIG. 13  shows a front view of a second embodiment of the door receptor of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0040]     In the drawings in FIGS.  1  to  2  there is shown biometric key  10  having a body  11  having a front surface  12  and a rear surface  13 . There is also shown a top component  14  in use and lower component  15  in use which are both attached to each other at a point  16 . The front surface  12  includes a sensor  17  surrounded by a recess  18 .  
         [0041]     In FIGS.  3  to  4  there is shown contact pins  19 ,  20  and  21  located in cavity  22  located at one end  23  of key  10  which is narrower in width than the other end  24 .  
         [0042]     In FIGS.  5  to  7  there is shown door controller receptor  25  having a plate like body  26  and attachment apertures  27  for attachment to a door (not shown). There is also shown recesses  28  for the head (not shown) of fasteners (not shown). The door controller receptor  25  is provided with a central hollow  29  and there are also provided stationary contacts  30 ,  31  and  32  which abut each spring loaded pins  19 ,  20  and  21  in use. Body  26  includes an attachment part  33  and an adjacent part  34  surrounding central hollow  29 . Part  34  also has contacts  30 ,  31  and  32  extending outwardly therefrom as well as support part  35  for contacts  30 ,  31  and  32 .  
         [0043]     In FIGS.  8  to  9  the key  10  is shown oriented in an aligned relationship with door controller receptor  25  with contact pins  19 ,  20  and  21  about to abut corresponding stationary contacts  30 ,  31  and  32 . Each of contact pins  19 ,  20  and  21  are provided with an inward bias by springs  36  upon touching contacts  30 ,  31  and  32 . Each contact pin  19 ,  20  and  21  is retained within a retaining socket  37  and each socket  37  is provided with a retaining flange  38  for retention with an adjacent recess (not shown) of peripheral end part  39  of body  11 . There is also shown circuit board  40  located in hollow compartment  41 . There are also provided attachment apertures  42  for fasteners (not shown) for retention of circuit board  40  within compartment  41 .  
         [0044]     In  FIG. 10  there is shown an overall circuit  50  which comprises a door controller circuit  60  and a key circuit  70 . The door controller circuit  60  includes a power supply  80  and a door receive/transmit circuit  90 . The power supply  80  is electrically connected to stationary contact  30 , the door receive/transmit circuit  90  is electrically connected to stationary contact  32  and stationary contact  31  is connected to ground. The key circuit  70  includes power/data circuits  100  and  110  and a key receive/transmit circuit  120 . The power/data circuit  100  is electrically connected to key contact  19 , the power/data circuit  110  is electrically connected to contact  21  and contact  20  is connected to ground. Power/data circuit  100  includes device U 4  having diodes  101  and  102  and power/data circuit  110  includes device U 5  having diodes  111  and  112 . Diodes  101  and  111  are in electrical communication with a key receive/transmit circuit  120  and diodes  102  and  112  are in electrical communication with a key 5V power supply  113 .  
         [0045]     The power supply  80  incorporates an LTC1474-5, which is a step down converter that ensures a constant 5 volt power supply. The power supply  80  also incorporates a 0.1 ohm resistor R 1 , which serves to program power supply  80  to deliver no more than 200 milliamperes to key circuit  70 , thereby protecting both door controller circuit  60  and key circuit  70  from short-circuit-induced overload.  
         [0046]     The door receive/transmit circuit  90  incorporates a SN74 ACOON chip which has four two input nand gates with only three nand gates  91 ,  92  and  93  being utilised. Also incorporated into receive/transmit circuit  90  are 100 ohm resistor R 2  and 10K ohm R 4  as well as switch  94  which is a HEXFET MOSFET model IRLM 2803.  
         [0047]     The key circuit  70  incorporates chips of a similar type to the door controller circuit  60  being an SN74 A COON chip having four two input nand gates, with only three nand gates  95 ,  96  and  97  being utilised. The key circuit  70  also includes a switch  71  of similar type to switch  94 . There is also shown 1 Kohm resistor R 3 .  
         [0048]     In use when key  10  is inserted into door controller receptor  25  each of contacts  19 ,  20  and  21  touch mating contacts  30 ,  31  and  32 . Thus when contacts  19  and  30  abut and contacts  21  and  32  abut power is therefore transmitted to key circuit  70  from power supply  80  with diode  101  preventing current from the 5V supply flowing into key receive/transmit circuit  120 . Simultaneously diode  102  allows power to be supplied to key circuit  70 .  
         [0049]     At the same time the key power 5V supply  113  is converted by suitable means such as a linear or switching voltage regulator  114  to a 3.3 voltage supply  115  whereby current is supplied through contact  21  to contact  32  to nand gate  92 . This means that a door controller microprocessor (not shown) which is incorporated into the door controller circuit  60  receives a signal indicating that key  10  has been inserted into the door controller receptor  25 . When the key  10  has been inserted the resistor R 3  raises the voltage on contact  32  from logic zero to logic 1, a state that is propagated to the door controller microprocessor through gates  92  and  91 . The state of logic zero is maintained in the absence of the key  10  by pull-down resistor R 4 .  
         [0050]     When the connection has been established between key  10  and the controller receptor  25 , binary communication can begin. When the switch  71  closes, a short circuit is created between resistor R 3  and ground which prevents current flowing from the 3.3 voltage power supply  115  to the door controller circuit  60  and hence creating a signal that can be interpreted by the door controller  60  circuit as a logic zero signal. When the switch  71  is open, current flows from the 3.3 voltage power supply  115  to the door controller circuit  60 , which is interpreted by the door controller circuit  60  as a logic one signal.  
         [0051]     The nand gates  91 ,  92 ,  93 ,  95 ,  96  and  97  control the multiplexing and demultiplexing of signals. Further, nand gates  91 ,  92  and  93  prevent the door controller circuit  60  from mistaking data that has been transmitted by the door controller  60  for data transmitted by the key circuit  70  and nand gates  95 ,  96  and  97  prevent the key circuit  70  from mistaking data that has been transmitted by the key circuit  70  for data that has been transmitted by the door controller circuit  60 . This communication process is coordinated by the microprocessor that is incorporated into the door controller circuit  60  and a microprocessor (not shown) that is incorporated into the key circuit  70 .  
         [0052]     The door controller circuit  60  transmits data after it has received a packet of data from the key circuit  70 . When the switch  94  opens, the voltage at a pair of inputs for the nand gate  95  is approximately 3 volts, which is interpreted by the key receive/transmit circuit  120  as a logic one. When the switch  94  is closed the voltage of inputs of the nand gate  95  is lowered to approximately 0 volts, which is interpreted as a logic zero by the key receive/transmit circuit  120 .  
         [0053]     When the key  10  is inverted, or rotated 180°, contacts  19 ,  20  and  21  abut contacts  32 ,  31  and  30 , respectively. When the contacts are arranged in this fashion diode  111  prevents current from the door power supply  80  entering the key receive/transmit circuit  120 . A key operator (not shown) who is left handed can hold the biometric key  10  in a first orientation and a key operator (not shown) who is right handed can rotate the biometric key  10  by 180° before inserting the biometric key  10  into the door controller receptor  25  in a second orientation. When the key  10  is inserted into door controller receptor  25  data signals can travel via diode  101  in the manner described above.  
         [0054]     When the biometric key  10  is inserted into the door controller receptor  25  there is an initial communication between the devices before the key microprocessor (not shown) attempts to acquire biometric data from a key operator (not shown) via the sensor  17 . It is best practise that a key operator (not shown) holds the biometric key  10  in such a fashion that their thumb is pressed against the sensor  17  to allow the sensor to acquire appropriate biometric data. When the identities of the key operator and the biometric key  10  have been determined and certified the door controller receptor  25  can operate a lock (not shown) and provide access to a secure environment.  
         [0055]     Referring to  FIGS. 11 and 12 , there is shown a second embodiment of a biometric key  130  that incorporates a body  140 , a front surface  150 , a rear surface  151  and a key blade  160 . The front surface  150  includes a sensor  170  situated in a recess  171 . The key blade  160  incorporates an earth  161 , a contact  162 , a contact  163  and insulation means  164  and  165 .  
         [0056]     The key circuit  70  is situated within the body  140  of the biometric key  130 . A person skilled in the art would appreciate that the key circuit  70  can be electrically connected to contacts  162  and  163  in a manner similar to that in which the key circuit  70  is electrically connected to contacts  19 ,  20  and  21 . The power/data circuit  100  is electrically connected to contact  162  and the power/data circuit  110  is electrically connected to contact  163 . Contact  161  is electrically connected to ground.  
         [0057]     Referring to  FIG. 13 , there is shown a key blade receptor  180 , which incorporates an opening  181 , standard lock mechanisms (not shown) and contact pins  182  and  184 . Each of the contact pins  182  and  184  are provided with in inward bias by springs  185  and are retained within a retaining socket  186 . Earth  161  contacts a corresponding earth contact (not shown).  
         [0058]     The door controller circuit  60  is situated within the body  140  of the key blade receptor  180 . The power supply  80  is electrically connected to contact pin  182  and the door receive/transmit circuit  90  is electrically connected to contact pin  184 . A person skilled in the art would appreciate that the power supply  80  is connected to contact pins  182  and  184  in a fashion similar to the connection of the power supply  80  to the stationary contacts  30 ,  32  and  31  of the door controller receptor  25 .  
         [0059]     When the key blade  160  is inserted in a first orientation into the key blade receptor  180 , the contacts  162  and  163  abut contact pins  182  and  184  respectively. When the key blade  160  is rotated 180° and inserted in a second orientation into the key blade  180  the contacts  162  and  163  abut contact pins  182  and  184 , respectively. Therefore, the biometric key  130  can communicate successfully with the door regardless of the orientation with which the key blade  160  is inserted into the key blade receptor  180 .  
         [0060]     During the insertion and removal of the key blade  160  into and from the key blade receptor  180 , the contacts  162  and  163  can make contact with contact pins  182  and  184  in a manner that results in the creation of short circuits. The current limiting of power supply  80  via R 1 , and the short circuit protection provided by R 2 , protect circuit  50  from damage that may result from the short circuits. When the key blade  160  is completely inserted into the key blade receptor  180  the insulation means  164  and  165  ensure that there are no short circuits between the contacts  161  and  163  and the contact pins  182  and  184 .  
         [0061]     Hence, the system and apparatus of the present invention provides a solution to the problem of maintaining polarity of connections and the problem of shorting of electrical contacts in biometric keys by virtue of the circuitry in the biometric key. This circuitry solves these problems without cumbersome electromechanical means.  
         [0062]     The key of the invention can thus be inserted into a door receptor in different orientations, independent of the alignment of the electrical contacts on the key and the electrical contacts on the door. These advantages allow the biometric key to be used by right and left handed individuals and can also ensure that a lock can be operated quickly and easily.  
         [0063]     Throughout the specification the aim has been to describe the invention without limiting the invention to any one embodiment or specific collection of features. Persons skilled in the relevant art may realize variations from the specific embodiments that will nonetheless fall within the scope of the invention.