Abstract:
In one aspect of the invention, a dual-mode infrared/radio frequency (IR/RF) transmitter is secured within a wristband worn by the mother and within an ankle and/or wristband worn by the infant. In a matching mode of operation, IR signals are received by infrared receivers located within the various rooms of the hospital to precisely and automatically determine by proximity that mother and infant are correctly united. In a presence detecting mode, RF signals from the infant&#39;s badge are detected by RF receivers located throughout the maternity ward of the hospital or throughout the hospital generally. In a security mode, RF receivers located proximate exits of either of the maternity ward and/or the hospital detect RF signals from the ankle and provide a signal to generate an alarm.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to security systems, and more particularly, the invention relates to a system for automatically verifying that a newborn infant is correctly matched with its parents and for ensuring the security of the newborn infant within a hospital. 
     2. Description of the Related Technology 
     The abduction of infants from hospital maternity wards happens with alarming frequency. The incorrect matching of newborn infants and parents also occurs much too often. That either of these events occur at all is unacceptable, particularly if it is your baby. 
     To ensure that mother and infant are correctly matched together, hospitals presently use a system of coded badges that are secured to each of the mother and the infant. Typically, a multi-digit code is printed on a wristband which is secured to the mother, and a wrist and/or ankle band bearing a matching multi-digit code is secured to the infant. The mother&#39;s badge is secured prior to delivery, and the infant&#39;s badges are secured as soon as practical after delivery while both the mother and infant remain in the delivery room. When mother and infant are later united, for example when the infant is brought from the nursery to the mother&#39;s recovery room, a hospital staff member is instructed to verify the numbers match to ensure the correct infant is united with the correct mother. Mothers are also encouraged to check that the numbers match. As an alternative to the infant wrist or ankle band, it has been proposed to imprint the code on an umbilical clamp and to provide the mother with a wristband again bearing a matching code. It is suggested that the umbilical clamp system ensures that the coded band does not inadvertently detach itself from the infant. With either wrist/ankle bands or umbilical clamps, the system requires human intervention to function correctly, and errors in matching mother and infant can still occur if the hospital staff or the mother fail to check or are careless in checking that the coded numbers match. 
     In spite of the care exercised by the hospital staff, the mismatching of mothers and infants continues to happen. The problem lies with the fact that there is no backup for the possibility of human error. For example, if an error is made when the infant is brought to its mother before discharge, it is possible that the mother may leave the hospital with the wrong infant before the error is detected. Furthermore, there is no positive feedback to either the mother or the hospital staff person making the matching verification that they have in fact correctly observed and matched the multi-digit numbers. 
     Infant abduction from hospital maternity wards it is sad to say is a growing problem. To combat such abductions, it has been proposed to provide radio frequency transmitters within the wrist or ankle band secured to the infant. Alternatively, magnetic strips or similar remotely excited circuits or materials may be placed within the wrist or ankle band. In still other proposed arrangements, the transmission device is secured within an umbilical clamp. Radio frequency receivers are positioned near exits from either the maternity ward and/or the hospital, and an alarm is sounded should an infant, wearing a transmission capable badge, be brought into proximity with the receiver. 
     To be effective, the radio frequency signals generated in the wrist and/or ankle bands have to be transmitted with sufficient strength to ensure that the infant is detected within the maternity ward and/or to ensure detection at the exit. However, transmitting the signals with increased power, i.e., such that they have sufficient signal strength to ensure detection, severely limits their usefulness for precisely locating the infant. This is because radio frequency signals will penetrate and pass through walls, floors, ceilings, and various other substantially non-conductive boundaries. So, while a radio receiver may be located in a room separate from where the infant is actually located, it may still be very much capable of receiving the signal from the infant&#39;s badge. In fact, the infant may be located in different rooms, on different floors, or outside of the hospital entirely. Therefore, it is impractical to use the radio frequency signals to locate the infant within the hospital. It has been suggested that relative signal strength indications (RSSI) along with triangulation may be used to better identify the location of a RF transmitter in a hospital application. However, RSSI value is greatly influenced by a number of factors including multi-path, Rayleigh fading, interference, and the like, limiting its effectiveness when used alone for identifying the precise location of the transmitter. 
     RF systems utilizing magnetic strips or other remotely excited circuits rely on detection of a resonant signal generated within the badge in response to an excitation signal to detect the presence of the badge near the reader. Unfortunately, these systems require the badge to be placed in close proximity and with proper orientation to the reader to be effectively energized and read. These systems fail as the badge can not always be in close proximity to a reader during matching of infant and mother. As precise location information is required to ensure proper matching of infant and mother, these RF systems are not viable for providing a matching function. 
     Infrared (IR) transmitters and receivers are commonly used in the hospital environment to locate equipment and personnel. The advantage of using IR signals for providing location information is that the IR signals do not penetrate walls, floors, ceilings or other substantially opaque boundaries. Thus, by locating an IR receiver in each room of the hospital, it is possible to know precisely which room within the hospital the transmitting device is located. Infrared signals, however, are easily blocked. If the transmitting device is disposed within a wristband or ankle band secured to an infant, and certainly within an umbilical clamp, it is likely that the signals will be blocked by clothing or blankets in which the infant is wrapped. Thus, IR technology, while offering the promise of providing precise location, does not provide the assured detection required for security purposes. 
     Thus, there is a need for a system which offers the capability to precisely locate both mother and infant within the hospital and to provide an indication that mother and infant are correctly matched. Additionally, the system must further have the capability to detect the presence of the infant within the hospital and to detect the attempted unauthorized removal of the infant from the maternity ward and/or the hospital. 
     SUMMARY OF THE INVENTION 
     A system in accordance with the preferred embodiments of the invention 1) ensures mother and infant are correctly matched postpartum, 2) continuously monitors the presence of the infant within the hospital and particularly within the hospital maternity ward, and 3) detects and signals the unauthorized removal of the infant from either the hospital maternity ward and/or the hospital entirely. 
     In one aspect of the invention, a dual-mode infrared/radio frequency (IR/RF) transmitter is secured within a wristband worn by the mother and within an ankle band and/or wristband worn by the infant. In a matching mode of operation, IR signals are received by infrared receivers located at various locations in and around the hospital to precisely and automatically determine by proximity that mother and infant are correctly united. In a presence detecting mode, RF signals from the infant&#39;s badge are detected by RF receivers located throughout the maternity ward of the hospital or throughout the hospital generally. In a security mode, RF receivers located proximate exits of either of the maternity ward and/or the hospital detect RF signals from the ankle band and/or wristband and provide a signal to generate an alarm. 
     In another aspect of the invention, an IR receiver and an RF receiver may be integrated into a single unit. 
     Another feature of the invention provides for an audio and/or visual signal for providing an indication mother and infant are correctly matched. 
     In still another aspect of the invention, each of the mother&#39;s wristband and the infant&#39;s badge are capable of providing an indication that mother and infant are correctly matched. 
     In yet another aspect of the invention, each of the IR signals and the radio frequency signals have a common modulation and are distinguished to the receiver by a header message. 
     In another aspect of the invention, the mother&#39;s wristband and/or the infant&#39;s ankle band include a motion sensor and capability of modifying its transmitted signal should it fail to detect motion associated with being secured to the mother or infant. 
     Still an additional aspect of the invention provides for each of the IR and RF signals to be sent in short bursts randomly distributed within a larger window of time. 
     An additional feature of the invention permits simultaneous use of numerous ankle bands within a single nursery without mutually interfering. 
     Another aspect of the invention provides packaged, ready to use dual-mode wristbands and/or ankle bands in sets to be matched upon initialization within the birthing room. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and the many other advantages and features of the invention will become apparent to those skilled in the art from the follow detailed description of several preferred embodiments read in conjunction with the attached figures wherein like reference numerals are used to represent like elements throughout and in which: 
     FIG. 1 is a schematic illustration of a hospital including a hospital maternity ward equipped with an infant and parent matching and security system in accordance with a preferred embodiment of the invention; 
     FIG. 2 is a block diagram illustration of an infant and parent matching and security system in accordance with a preferred embodiment of the invention; 
     FIG. 3 is a block diagram of a hospital information management system incorporating an infant and parent matching and security system in accordance with the invention; 
     FIGS. 4 a - 4   c  illustrate in perspective an infant dual IR/RF badge in accordance with a preferred embodiment of the present invention being attached to an infant; 
     FIG. 5 is an exploded assembly perspective of the infant dual IR/RF badge illustrated in FIGS. 4 a - 4   c;    
     FIG. 6 is a cross-section view taken along line  6 — 6  of FIG. 4 a  and with the infant dual IR/RF badge in an open position; 
     FIG. 7 is a cross-section view taken along line  7 — 7  of FIG. 4 c  and with the infant dual IR/RF badge in a closed position; 
     FIG. 8 is a cross-section view taken along line  8 — 8  of FIG. 4 c;    
     FIGS. 9 a - 9   c  illustrate in perspective an infant dual IR/RF band in accordance with an alternate preferred embodiment of the present invention being attached to an infant; 
     FIGS. 10 a - 10   c  illustrate in perspective an infant dual IR/RF badge in accordance with an alternate preferred embodiment of the present invention being attached to an infant; 
     FIGS. 11 a - 11   c  illustrate in perspective an infant dual IR/RF badge in accordance with an alternate preferred embodiment of the present invention being attached to an infant; 
     FIG. 12 is perspective view of a parent dual IR/RF badge in accordance with a preferred embodiment of the invention; 
     FIG. 13 is a plan view of the parent dual IR/RF badge shown in FIG. 12; 
     FIG. 14 is a cross-section view taken along line  14 — 14  of FIG. 13; 
     FIG. 15 is a plan view of a preferred electronics package for use in either the infant dual IR/RF badge or the parent dual IR/RF badge; 
     FIG. 16 is a side elevation view of the electronics package illustrated in FIG. 15; 
     FIG. 17 is a block diagram illustrating the operative elements of a dual IR/RF badge in accordance with the invention; 
     FIG. 17 a  is a block diagram illustrating the operative elements of an IR only badge in accordance with the invention; 
     FIG. 18 is a block diagram illustrating an IR receiver in accordance with the invention; 
     FIG. 19 is a block diagram illustrating an RF receiver in accordance with the invention; 
     FIG. 20 is a diagram illustrating a communication modulation scheme in accordance with a preferred embodiment of the invention; 
     FIG. 21 is a diagram illustrating a data transmission protocol in accordance with a preferred embodiment of the invention; 
     FIGS. 22 a - 22   d  are timing diagrams illustrating data transmission in a first operative state and in accordance with a preferred embodiment of the invention; 
     FIGS. 23 a - 23   c  are timing diagrams illustrating data transmission in a third operative state and in accordance with the invention; 
     FIG. 24 is a block diagram illustrating operative elements that may be adapted to either a parent badge or an infant badge in accordance with an alternate embodiment of the invention; 
     FIG. 25 is a block diagram illustrating operative elements that may adapted to an IR reader in accordance with an alternate embodiment of the invention; 
     FIGS. 26 a - 26   f  are timing diagrams illustrating data transmission in a parent/infant matching and security system utilizing parent badges and infant badges shown in FIG. 24; 
     FIG. 27 is a flow chart illustrating a method of matching a parent with an infant in accordance with the invention; 
     FIGS. 28 a - 28   d  are timing diagrams illustrating data transmission in a second operative state and in accordance with a preferred embodiment of the invention; 
     FIG. 29 is a diagram illustrating an alternate method for location determination in accordance with the invention; 
     FIG. 30 is a block diagram illustrating an RF signal detection circuit in accordance with the invention; and 
     FIG. 31 illustrates data detection in accordance with the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference now to FIG. 1, within a hospital  1 , a hospital maternity ward  10 , includes a plurality of patient rooms  12  in proximity to Cesarian delivery rooms  8 , delivery rooms  9 , delivery staging area  11 , nursery  14 , care service station  16 , recovery rooms  15 , staff locker rooms  17 , and emergency care area  18 . Of course the invention has application to any hospital and/or maternity ward layout, and is further adaptable to associated neo-natal intensive care rooms, operating rooms and other portions of the hospital associated with the delivery and care of pre- and post-partum mothers and newborn infants. Still further, one of ordinary skill in the art will appreciate the applicability of the invention in other matching/security applications generally for persons or objects. 
     In accordance with the preferred embodiments for the invention, and with continued reference to FIG.  1  and with reference to FIG. 2, each patient room  12  is fitted with an infrared (IR) signal reader (referred to herein as IR reader  20 ). An additional IR reader  20  is located within staging area  11 , nursery  14 , recovery rooms  15 , near care service station  16  and emergency care area  18 . At various other locations of the ward  10 , and particularly within common areas, hallways and near exits  11  from the ward  10  there is fitted a radio-frequency (RF) reader  21 . Additionally, and as best seen in FIG. 1, one or more IR readers  20  and RF readers  21  may be positioned near hospital entrance  2 , hospital secondary entrance and exit  4  or generally along the hallways  6  of the hospital  1 . 
     Referring still to FIG. 2, each IR reader  20  and RF reader  21  is coupled, preferably via a LonTalk network  22 , to a central server  24 . Further coupled to the network  22  adjacent central server  24  is an input/output station (not depicted). Optionally coupled to either IR reader  20  or RF reader  21  is an external device controller  26 . Each external device controller  26  is adapted to provide control signals to external devices, such as lighting systems, heating/ventilation controls, and the like. More preferably, the external device controller  26  permits coupling to an audio or visual alert device  38  capable of providing visual and audio indications of the correct or incorrect matching of a parent and infant and the unauthorized removal of an infant from a secured area. However, the alert devices may be coupled directly to network  22  as shown by alert devices  38 ′. An audio or visual alert device  38  or  38 ′ is positioned within each patient room  12 . Each display device  38  may be a scrolling text display, a light display, or virtually any suitable display device. For example, the patient&#39;s in-room television may be adapted to act as the display. Display device  38  may also include audio capability allowing the sounding of voice signals, tunes and alert tones. 
     Upon admission to the hospital, the expecting mother is provided with a mother identification badge (referred to herein as mother badge  30 ), which is operable to provide both an IR identification signal  34  and a RF identification signal  36 . Authorized persons, such as nurses, are issued badges  29  that may provide both an IR identification signal and a RF identification signal, but more typically provide only IR signals. The following discussion with respect to the mother badge  30  is applicable to such authorized persons badges  29 . In accordance with the invention, each badge  30  is matched to one or more infant identification badges (referred to herein as infant badge  32 ). By saying each mother badge  30  is matched to one or more infant badges  32 , each mother badge  30  and infant badge  32  is operable to provide both an IR identification signal  34  and a RF identification signal  36  containing identification information. Preferably, within server  20 , the identification information from the mother badge  30  is mapped to identification information for the infant badge  32  within a central database contained within server  20 . Alternatively, each of the mother badge  30  and the infant badge  32  may be programmed such that each of the badge&#39;s identification information contains matching data. While an authorized person is not, per se, matched with an infant, identification of the authorized person is used in the invention to permit that person to move an infant between rooms within ward  10  or to remove an infant entirely from ward  10 . 
     In accordance with the invention, the IR reader  20  in each patient room  12  receives the IR identification signals  34  from each mother badge  30  and infant badge  32  located within the patient room  12 . Because IR transmission will not penetrate opaque surfaces, such as walls, doors, floors and ceilings, the IR identification signals  34  are substantially confined to within the particular patient room  12 . The RF identification signals are capable of penetrating opaque but non-conducting surfaces, and the RF readers  21  receive the RF identification signals from each mother badge  30  and infant badge  32  located within a reception range of the RF reader  21 . Thus, the RF readers  21  receive the RF identification signals from each mother badge  30  and each infant badge  32  located within the ward  10 . The RF readers  21  further receive identification signals from badges located in other but nearby locations of the hospital. 
     The server  24  may be a standalone server for use with the infant security and monitoring system, or may be implemented as part of a hospital security system or other building information management system which is advantageously facilitated by use of the LonTalk network architecture for network  22 . In a standalone application, server  24  is at least coupled to communicate with the hospital security system. Server  24  is preferably implemented using a multi-purpose computer such as an Intel processor based personal computer running the Windows operating environment. It will be appreciated, however, that various other multi-purpose computing platforms may be used to implement server  24 . Each input/output station  28  permits access to server  24  for observing the operation and status of the system  1 . 
     Each IR reader  20  also includes local processing capability. Local processing capability allows each IR reader  20  to provide decoding and processing of the received IR identification signals  34 . Each RF reader  21  also includes similar processing capability and the following discussion is equally applicable thereto. In accordance with a preferred embodiment of the invention, each IR reader  20  may therefore be operable to determine if both a mother badge  30  and an infant badge  32  transmitting matching identification information are within the reception range of the IR reader  20 . With a mother and an infant located within a patient room  12 , and upon initiation of a matching process, the IR reader  20  within the patient room  12  receives and decodes the identification information from each of the mother badge  30  and the infant badge  32 , providing each badge is optically exposed to the IR reader  20 , and provides a signal indicating mother and infant have been correctly matched together. 
     In a preferred embodiment, each display device  38  is operable to provide visual messages, such as scrolling text and/or flashing lights. For example, upon detection of the correct matching of a mother and infant, the mother&#39;s and infant&#39;s names may be scrolled across the display in a first color, such as green. If an incorrect match is detected, a message as well as the identification of the mother&#39;s and infant&#39;s names may be scrolled in a different color, such as red, to indicate the incorrect matching. The message may also be flashed to draw further attention to the incorrect matching. Display devices  38  may also include audio capability to play speech segments, tunes, alert tones, and the like in connection with the matching process. In addition, each IR reader  20  may also include an indicator lamp. The indicator lamp may illuminate if a correct match is made or may flash during the matching process indicating system operation. IR reader  20  further provides a signal to server  24  via network  22 , and the database within server  24  is then updated with the present locations of both the mother and the infant. 
     Referring now to FIG. 3, the functional elements of server  24  are illustrated. Central to server  24  is a real time engine  40  having directly coupled thereto an installation module  42  and which is linked to a client server driver  44 . The client server driver  44  is an optional element which supports the addition of client stations  46  from server  24  and may be an ethernet driver or similar networking device. An additional optional element is a user applications module  48  supporting a plurality of user applications  50 . User applications  50  may include links to other hospital systems, external system access, Internet access, and similar type applications. Two additional modules include a systems administration module  52  and installation interface  54 . Administration module  52  permits access to engine  40  for administering the database contained therein and/or otherwise modifying the operating parameters of system  1 . 
     With continued reference to FIG. 3, engine  40  is operatively coupled to network  22  via a network interface driver  56 . Driver  56  is preferably a LonTalk network driver coupling engine  40  to network  22 . Also provided is a system application interface  58  operatively coupling to a plurality of system applications  60 - 70 . Directory view  60  and map view  62  provides directory listing of hospital personnel and patients and graphical display of maternity ward  10 , respectively. History processor  66  and external device control  70  are optional modules. If network  22  includes external device controllers  26 , commands are to these controllers are processed through external device control  70  and messaged via network  22  to the appropriate external device controller  26 . History processor  66  is operable to maintain a running history of system operation and to record this history in an appropriate database associated with the system. 
     With reference now to FIGS. 4 a - 4   c,  an infant badge  100  in accordance with a preferred embodiment of the invention for use with system  1  includes a housing  102 , a strap  104 , a lens  106  and a strap coupling  108 . Housing  102  is preferably a stylized oval or egg shaped member formed of plastic or plastic coated with an elastomer to provide a soft, non-abrasive surface. Strap  104  is preferably formed from an elastomer, and while shown as a round cord, may have a flattened configuration with rounded portions extending through strap coupling  108 . In addition, strap  104  further includes embedded therein at least one conductor, which preferably comprises braided copper wire. Initial strap  104  is pre-looped through strap coupling  108  forming a loop  110  sufficiently large to easily secure over a foot  112  or hand of an infant. The ends  114  of strap  104  may be joined to prevent them from become disengaged from strap coupling  108 . Lens  106  is preferably formed from an IR transparent plastic. 
     Referring to FIG. 4 b,  with loop  110  positioned over foot  112 , ends  114  are drawn through strap coupling  108  snugging strap  104  around the infant&#39;s lower leg  116 . With strap  104  snug, but not too tight, strap coupling  108  is depressed with respect to housing  102 , cutting ends  114  and activating infant badge  100 , FIG. 4 c.    
     With attention directed to FIGS. 5-8, housing  102  is formed from a first housing  118  and a second housing  120 , sonically welded, bonded or otherwise secured together. At a strap interface portion  122 , housing  102  forms a generally cylindrical cavity  124  from which a plurality of upwardly (as viewed in FIG. 5) extending flanges  126  extend from ribs  128  formed within cavity  124 . Each flange  126  includes an inwardly extending tab  130 . Further formed within cavity  124  is a pair of contact members  132 . Each contact member  132  includes a substantially rectangular boss portion  134  extending upwardly from cavity and a metalized contact portion  136  which couples to a transmitter (not shown in FIG. 5) retained within housing  102 . A second pair of bosses  138  are formed in cavity  124  opposite but substantially aligned with contact members  132 . Each boss  138  also has a generally rectangular shape extending upwardly from within cavity  124 . 
     Formed as a separate assembly is strap coupling  108 . Strap coupling  108  has a circular base  140  formed with two contact cavities  142  each having a portion  144  extending below circular base  140  and a portion  146  extending above base  140 . Each portion  144  is formed with two apertures  150  sized to receive a respective contact member  132  and boss  138 . On an outer wall  146  of each cavity  142  is a flange  148  adjacent an aperture  149  formed in base  140 . Aperture  149  is sized to provide clearance for flanges  126 . Disposed within each contact cavity  142  is an insulation displacement contact/cutter (IDC)  152 . Each IDC  152  has a horizontally extending plate member  151  formed with upwardly extending leg portions  154  and  156  at opposite ends thereof Each leg portion  154  includes a cutting edge  158  for engaging and cutting a portion of strap  104 . Each leg portion  156  is formed with a “V” shaped channel  160  including a wire notch  162  at its base. A cover  164  is provided which is sonically welded, bonded, or otherwise secured to base  140  enclosing each IDC  152  in a respective contact cavity  144 . 
     With particular reference to FIGS. 6-8, strap  104  is captured between base  138  and cover  164 . A first portion is disposed in recesses  166  and a second portion is disposed in recesses  168  formed in base  140 . Cover  164  is further formed with downwardly extending flanges  174 - 180  that also include recesses, shown as recesses  170  and  172  in FIG. 8, and strap  104  is further received therethrough. 
     As shown in FIG. 6, base  140  is positioned over cavity  124  and apertures  150  are aligned with contact members  132  and bosses  138 . As strap coupling  108  is pressed downward, FIGS. 7 and 8, contact members  132  and bosses  138  pass through apertures  150  and bear against a bottom surface of IDCs  152 . Flanges  176 - 180  press strap  104  downwardly against IDCs  152 . Edge  158  severs ends  114 . In addition, strap  104  is engaged in “V”  160  which displaces the outer elastomer portion of strap  104  and engages the conductor  182  into wire notch  162 . Conductor  182  is coupled to IDCs  152  which in turn is coupled by contacts  136  with the transmitter portions disposed within housing  102 . As will be described more fully herein below, coupling of strap  104  with the transmitter portion activates infant badge  100  and further permits detection of tampering with badge  100 . Strap coupling  108  is retained to housing  102  by the engagement of tabs  130  with flanges  148 . Strap coupling  108  may be removed from housing  102  by accessing tabs  130  via apertures  165  formed in cover  164 . 
     Referring now to FIGS. 9 a - 9   c  an infant badge  200  in accordance with an alternative preferred embodiment of the invention is shown. Infant badge  200  includes a housing  202 , a strap  204 , and a strap coupling  208  including a lens  206 . Housing  202  preferably has a stylized flower shape with strap coupling  208  forming a central portion thereof. Housing  202  is preferably formed of plastic or plastic coated with an elastomer to provide a soft, non-abrasive surface. Strap  204  is preferably formed from an elastomer having a flattened configuration with a portion extending through strap coupling  208  In addition, strap  204  further includes embedded therein at least one conductor, which preferably comprises braided copper wire. Initially strap  204  is pre-looped through strap coupling  208  forming a loop  210  sufficiently large to easily secure over a foot  112  or hand of an infant. 
     Referring to FIG. 9 b,  with loop  210  positioned over foot  112 , end  214  is drawn through strap coupling  208  snugging strap  204  around the infant&#39;s lower leg  116 . With strap  204  snug, but not too tight, strap coupling  208  is depressed with respect to housing  202 , cutting ends  214  and activating infant badge  200 , FIG. 9 c.    
     Referring now to FIGS. 10 a - 10   c  an infant badge  300  in accordance with an alternative preferred embodiment of the invention is shown. Infant badge  300  includes a housing  302 , a strap  304 , a lens  306  and a strap coupling  308 . Housing  302  is preferably disk shaped with strap coupling  308  extending from a rear portion thereof. Housing  302  is preferably formed of plastic or plastic coated with an elastomer to provide a soft, non-abrasive surface. Strap  304  is preferably formed from an elastomer having a flattened configuration formed with a plurality of apertures, one of which is shown as  305 . Strap coupling  308  includes a pin  309  adapted to engage one of the plurality of apertures  305  with a portion extending through strap  304  and into a locking aperture  311  formed adjacent housing  302 . Strap  304  further includes embedded therein at least one conductor, which preferably comprises braided copper wire and a portion which bridges each of the plurality of apertures. 
     Referring to FIG. 10 b,  strap  304  is positioned around lower leg  116  forming a loop  310 . One of the plurality of apertures  305  is aligned with the locking aperture  311 , and pin  309  is engaged with the aperture  305  and locking aperture  311 . Pin  309  engages the conductor within strap  304  activating badge  300  shown in FIG. 10 c.  An end  314  of strap  304  may then be trimmed using scissors. 
     With reference now to FIGS. 11 a - 11   b,  an infant badge  400  in accordance with still an additional preferred embodiment of the invention for use with system  1  includes a housing  402 , a strap  404 , a lens  406 . A strap coupling is provided and integrated into housing  402  and is actuated by depressing lens  406 . Housing  402  preferably has a rounded shape formed of plastic or plastic coated with an elastomer to provide a soft, non-abrasive surface. Strap  404  is preferably formed from an elastomer having a flattened configuration and adapted to extend through housing  402 , and hence through the integrated strap coupling. In addition, strap  404  further includes embedded therein at least one conductor, which preferably comprises braided copper wire. 
     Referring to FIG. 11 b,  strap  404  is looped through an aperture  408  in housing  404  forming a loop  410  around the infant&#39;s lower leg  116  and thereby position strap within the integrated strap coupling. With strap  404  snug, but not too tight, strap coupling is actuated by depressing lens  406  with respect to housing  402 . This action cuts end  414  and activates infant badge  400 , FIG. 11 c.    
     Referring now to FIGS. 12-14, a parent badge  500  in accordance with a preferred embodiment of the invention is shown. Parent badge  500  includes a housing  502  adapted to be secured to a strap  504  via a pair of apertures  506  formed in outwardly extending flanges  508 . Formed in a center portion of housing  502  is a lens  510  formed from an IR transparent plastic. Along an edge of housing  502  is a push-button  512 , which is offset within a shroud  514 . Strap  504  is preferably removable from housing  502 , and is further preferably arranged for single use and destructive removal. 
     Referring particularly to FIG. 14, disposed within housing  502  is a transmitter  516  according to a preferred embodiment of the invention. Transmitter  516  is arranged to provide both RF identification signal  36  and IR identification signal  34 . It is further sized such that it may be disposed in any of housings  102 ,  202 ,  302  and  402  of the preferred infant badges  100 ,  200 ,  300  and  400 , respectively, as well as within housing  502  of a parent badge. Push-button  512  couples through housing  502  and engages a momentary switch formed as part of transmitter  516 . 
     Still referring to FIG. 14, housing  502  preferably includes a lower molded plastic member  518 . Lens  510  may then form an upper portion of housing  502  and accordingly include a downwardly extending flange  520  extending about a circumference thereof and engaging a surface  522  of member  518 . Lens  510  is either sonically welded, bonded or otherwise secured to member  518 . Member  518  further includes a flange  524  upon which a portion of a printed circuit board (PCB)  526  of transmitter  516  is disposed and secured. Flange  524  forms a cavity  528  into which a battery  530  retained, and transmitter  516  is positioned above battery  530  with a second PCB  532  in operable engagement therewith. 
     Transmitter  516  is described in more detail now with reference to FIGS. 15-17. On an upper surface  534  of PCB  526  are a plurality of IR light emitting diodes (LEDs)  536 , an RF antenna  538 , a programming photo-diode  540  and a transmitter integrated circuit (IC)  542 . LEDs  536 , antenna  538 , photo-diode  540  and IC  542  may be selected from commercially available components, and for example, LEDs  536  and photo-diode  540  are available from Siemens while IC  542  is available from Temic (part number U2740b). Transmitter  516  further includes coupled to PCB  532  a motion sensor  544 , a microcontroller  546  and additional resistor, capacitor and diode components as is well-known in the art of circuit design. Microcontroller  546  may be a part number PIC12C5xx controller available from Microchip. Motion sensor  544  is preferably an electromechanical or piezo-type motion sensor. Battery  530  is preferably a 3.0 volt lithium battery and is commercially available from Renata. The actual layout and construction of PCB  526  and PCB  532  may be altered to accommodate different housing dimensions and applications, and thus, the transmitter  516  illustrated in FIGS. 14-16 is intended to be illustrative only of a potential layout. In this regard, FIG. 17 shows transmitter  516  in block diagram form to provide further understanding of the operative coupling of its functional elements, while FIG. 17 a  illustrates an IR only transmitter  516 ′similar in construction to transmitter  516  without RF transmission capability. Like reference numerals identify like elements between transmitters  516  and  516 ′. 
     Battery  530  and motion sensor  544  are coupled to microcontroller  546 , which, in turn, is coupled to LED  548 , momentary switch  552  (which is actuated by push button  512 ), and a non-volatile memory  554 . LED  548  provides a very precise voltage reference, and may be used to perform contactless programming wherein LED  548  acts as a photo-detector to receive programming signals. Outputs from microcontroller  546  are coupled to an RF modulator  556  and an IR modulator  558 . RF modulator  556  is further coupled to an RF transmitter  560  and then to antenna  538 . RF modulator  556  and RF transmitter  560  are preferably integrated into IC  542 . As noted, a preferred IR modulation technique is on-off keying (OOK) modulation, and thus IR modulator  558  may be implemented as a switching device. IR modulator  558  is then coupled to an IR transmitter  560  and then to IR LEDs  536 . 
     As shown in FIG. 18, each IR reader  20  includes a microcontroller  602  coupled to an Echelon Neuron chip  604  through which it couples to a LonTalk network interface  606  into network  22  via a twisted pair coupling  608 . Microcontroller  602  is further coupled to a non-volatile memory  610 , to an external device controller  26  (if installed) and to alert devices  38 . Further coupled to microcontroller  602  is an IR receiver  612  which includes an IR photo-diode array  614  for receiving IR identification signals  34 . A switching power supply is also provided operatively coupled to the respective elements of IR reader  20 . IR receiver  612  provides to microcontroller  602  at least a signal detect indication, a signal strength indication and a data signal via parallel bus  616 . 
     As shown in FIG. 19, each RF reader  21  includes a microcontroller  702  coupled to an Echelon Neuron chip  704  through which it couples to a LonTalk network interface  706  into network  22  via a twisted pair coupling  708 . Microcontroller  702  is further coupled to a non-volatile memory  710 , to an external device controller  26  (if installed) and to alert  38 . Further coupled to microcontroller  702  is a data demodulator  712  coupled to an RF receiver  714  which is coupled to an antenna  716  for receiving RF identification signals  36 . A switching power supply  718  is also provided operatively coupled to the respective elements of RF reader  21 . RF identification signals are received by RF receiver  714  and demodulated by data demodulator  712 . Demodulator  712  provides to microcontroller  702  at least a signal strength indication and a data signal via parallel bus  720 . Virtually any RF modulation scheme may be employed, and in a preferred embodiment amplitude shift keying (ASK) modulation is utilized. As should be appreciated from the foregoing discussion a single IR/RF reader may be constructed owing to the substantial reuse of components. 
     Referring to FIGS. 20 and 21, each transmission, whether IR and OOK modulated or RF and ASK modulated, comprises a preamble portion  802  followed by a plurality of data words  804 . Between 4 and 31 data words may be sent in a transmission. Each data word is identified by a start bit  806 , and is concluded with a stop bit  808 . The modulation illustrated is OOK for the IR transmissions. RF data is transmitted with a preferred modulation, such as ASK modulation, and the RF data is preferably distinguished based upon the preamble data. This advantageously allows the receiver circuitry following the signal reception and demodulation portions to be made common. 
     With reference now to FIGS. 22 a - 22   d,  to provide statistical signal separation of the RF identification signals  36  and the IR identification signals  34 , and to hence reduce interference created by a plurality of either parent badges  30  or infant badges  32  operating in one area, motion sensor  544  is used to initiate transmission of signals  34  and  36 . In FIG. 22 a,  a motion detect flag is enabled, and the badge controller  546  operates in a motion detect mode. The output of the motion sensor  544  is monitored, and upon receiving a motion detect signal from motion detector  544 , FIG. 22 b,  the motion detect flag is disabled. Transmission of IR identification signal  34  is initiated. As shown in FIG. 22 d,  IR identification signal may be sent in a t p  ms (preferably about 2 ms) burst approximately every t 1  to t 2  seconds (preferably about 3 to 5 seconds). Following transmission of IR identification signal  34  by a delay period t d  (preferably about 4 ms), transmission of RF identification signal  36  is initiated, FIG. 22 c.  Similarly, RF identification signal  36  is preferably a t p  ms burst signal, and it is transmitted timed to the transmission of IR identification signal  34 . Most preferably, each of IR identification signal  34  and RF identification signal  36  contain the same data identified by a preamble message. After transmission of n bursts (preferably about 7), the motion detect enable signal is reset high, and the cycle is repeated upon once again detecting a motion disable signal. 
     As noted, by initiating transmission based upon a signal from motion detector  544  randomness is introduced to the signaling process. Moreover, the period for transmitting the signals is randomly varied from between 3-5 seconds. This provides substantial statistical separation allowing use of common IR and RF carriers without interference. A preferred IR carrier is 455 kHz, while a preferred RF carrier is in the ultra-high frequency (UHF) spectrum. 
     FIGS. 23 a - 23   c  illustrate operation with the motion detect enable signal high. After a random period following a motion detect enable signal, an IR transmission of the IR identification signal  34  is initiated. As before, following a fixed time period after signal  34 , RF transmission of the RF identification signal  36  is initiated. Now, however, a delay  60  of seconds occurs before the IR identification signal  34  and RF identification signal  36  are resent. This operation further reduces mutual interference by reducing the number of transmissions and by also introducing randomness to the transmissions as described above. 
     As will be appreciated, the invention allows, by randomly separating transmissions and keeping transmissions confined to short bursts as described, a large number of badges to operate within ward  10  without mutual interference. Referring to FIG. 24, the number of IR and RF transmissions may be further reduced by providing a modified mother badge  30 ′ (an infant badge  32  may be similarly configured) with an IR detector  564  coupled to an IR receiver  566 , which provides an IR detection signal to controller  546 ′ adapted to receive and process the received signal and to generate a response thereto as described below. Mother badge  30 ′ is as otherwise discussed with respect to mother badge  30  and like reference numerals are used to identify like elements. Mother badge  30 ′ is operable in conjunction with IR receiver  20 ′ (FIG.  25 ). IR receiver  20 ′ is similar in construction to IR receiver  20 , and like elements are identified with like reference numerals. IR receiver  20 ′ further includes an IR modulator  620  couple to controller  602 ′, an IR transmitter  622  and a transmitting LED  624 . Controller  602 ′ is operable to generate an acknowledgment signal  626 , as described below, that is transmitted via the IR modulator  620 , IR transmitter  622  and transmitting LED  624 . If the IR acknowledgment signal  626  is detected and decoded by mother badge  30 ′ (or a properly configured infant badge  32 ), RF transmissions are suspended. If the acknowledgment signal is not received and decoded, then the mother badge  30 ′ transmits both the IR and RF identification signals  34  and  36 , respectively, as previously described. 
     Referring to FIGS. 26 a - 26   f,  and again discussing the operation of the mother badge  30 ′ (the operation of a modified infant badge  32  being similar) is discussed in more detail. The mother badge  30 ′ transmits IR signals  906  having a t p  ms duration every t 1 -t 2  seconds. The signals  900  are detected by the IR reader  20  and decoded as signals  902 . The mother badge  30 ′ listens for an acknowledgment  904 , a pulse of t a , during a listening window  906  of duration t win . If the IR reader  20  successfully decodes the signals  902 , the IR reader  20  transmits, using IR, an acknowledgment signal  904 . The acknowledgment signal  904  is received by the mother badge  30 ′ and decoded as signal  905 , and in response thereto, mother badge  30 ′ suspends transmission of the RF signals. Should the reader fail to decode the signals  902 , for example signal  902 ′ shown in phantom, or if the mother badge  30 ′ fails to detect the acknowledgment signal  904 , RF signals  908  are transmitted. By so reducing the number of RF transmissions, the likelihood of badges mutually interfering is greatly reduced. It will be appreciated that a similar strategy or suspending IR transmissions in favor of RF transmissions may be employed without departing from the fair scope of the present invention. 
     The invention provides the capability of automatic or manual matching. Referring to FIG. 27, the manual matching process  1000  is initiated by the mother first unwrapping the infant to disclose the infant badge  32 , step  1004 , and pressing the push-button  552  provided with mother badge  30 , step  1006 . This initiates a matching process by transmitting the IR identification signal  34  and the RF identification signals  36 . The identification data, as will be described more fully below, is preferably sent in a rapid succession of bursts followed by less frequent repeated bursts. This ensures immediate detection by the IR reader  20  located within the room with the mother. Upon detection of the mother&#39;s badge identification data, step  1008 , the IR reader  20  then looks for and detects IR identification signals  34  from an infant badge  32  located within its range, step  1010 . If the identification data in each of the signals matches, step  1012 , display device  38  is caused to display appropriate matching data. Also, the database information is updated within server  24 , step  1016 , and after a period of time, such as about 1 minute, the display is turned off, step  1018 . If the match fails, display device  38  displays the failed matching data, step  1020 , such as flashing red, and indicating in text that a match has not taken place. Again, the database information is updated in server  24 , step  1022 , and after a predetermined period of time, such as about 1 minute, the display is turned off, step  1024 . If the infant IR data is not detected, step  1010 , the display may indicate to disclose the badges and repress the button  552  to restart the matching process, step  1026 . If the mother badge  30  IR signals are not detected, step  1008 , and the RF signals are also not detected, step  1028 , there is no response. However, if the IR signals are not detected, step  1008 , but the IR signals are detected, step  1028 , then the display indicates that the button should be repressed to restart the matching process, step  1030 . 
     An automatic process may also be implemented. In the automatic process, the mother&#39;s badge  30  transmits the IR identification data regularly in response to detected motion as described below. The matching process then continues as described. 
     As described, the strap  104  of the infant badges  32  contains a conductor  182 . The conductor engages contacts  156  through operation of the strap coupling  108  to complete a loop. Upon detection of a completed loop, the transmitter becomes activated and begins transmitting. Most preferably, an initiation is accomplished with the system whereby information necessary to identify the badge is transmitted to the system and the database is automatically updated. Alternatively, a manual initiation process may be employed. The automatic process is preferred as it reduces the likelihood of introducing error. 
     The conductor  182  also provides an ability to detect tampering with the strap  104 . Should the strap  104  be cut or the strap coupling  108  opened, the loop is broken. After activation if the loop is broken, an alert signal is transmitted with priority to indicate tampering. It is also possible to have the transmitter detect a resistance of the conductor  182 . In this arrangement, a conductor having a resistance sensitive to strain would be used. Thus, if the strap  104  is stretched in order to remove the infant badge  32  from the infant, the change in resistance after activation can provide an indication of tampering and an alert signal may be sent. Most preferably, the conductor  182  is selected with a strength such that it will fail and open circuit should the strap  104  be stretched excessively. 
     Referring to FIGS. 28 a - 28   d,  signal transmission during either of the manually initiated matching process and/or should the infant badge  32  strap  104  be tampered with is illustrated. As shown in FIG. 28 a,  a button pulse  1102  is detected or as shown in FIG. 28 b  a wire cut signal is pulled high  1103 , and in response thereto, a rapid series of data pulses  1104  are transmitted. For example, as shown in FIGS. 28 c  and  28   d,  4 IR pulses may be sent in series, where each signal is a pulse of duration t p  transmitted every t 3  seconds. As described above, 4 RF pulses, timed to the IR pulses, may also be sent in series following respective ones of the IR pulses. If the pulse series is initiated as the result of the infant badge  32  strap  104  being cut or tampered with, a pulse  1106  is then sent every t 4  seconds (approximately every 3-5 seconds). 
     Several alert signals of differing priority are contemplated by the invention. For example, a soft alert may be provided where an infant is removed from nursery. It would be common for the infant to be moved from the nursery to the mother&#39;s recover room or to other parts of the maternity ward. If the infant is removed from the maternity ward, a higher level alert may be initiated. The soft alerts may be identified only at the server  24 , and may be overridden by a user having the appropriate authority. 
     Higher level alerts may be used for instances where the infant is not matched with the correct parents. Matching is determined, as discussed, by decoding and comparing the IR identification signals. Also, if the infant is brought near an exit of the maternity ward or hospital, a high level alert would also be employed, and preferably an alert is sent to the hospital security staff via the hospital security system. Of course it will be appreciated that numerous alert levels and occurrences triggering such alerts may be employed with the invention without departing from its fair scope. 
     Referring to FIG. 29, while it is noted that RF transmissions do not provide accurate location data, it is possible to use RSSI data to provide indications of location. The RF identification signals are transmitted with very low power, and preferably about −20 dbm, or 0.00001 watt. Thus, even though these signals will penetrate opaque, non-conducting surfaces they do not travel far. This short range may be used to detect that a badge has been moved away from a first RF reader and nearer to a second RF reader  21 . Change of location is established only when the difference between the RSSI level of a received signal is more than a predetermined number of units from the RSSI level in the present location. For each received signal, that is for each badge, the signal sent from the reader  21  to the server  24  has attached the RSSI signal level and a noise level as received at the receiver. The server  24  may then use this data to provide location detection when the badge RF signals are received at several different readers. In addition, strategic location of RF readers within the hospital  1  can ensure a sufficient change in RSSI levels as a badge is brought near an exit of the ward  10  or hospital  1  for providing security. Upon detecting an infant badge  32  near an exit, for example, without approval an alarm condition is created. 
     In this regard, and with reference to FIGS. 29 and 30, the data demodulator  712  of the RF reader  21  is constructed to provide RSSI signal level detection and noise level in addition to providing the demodulated data. A frequency mixer  1202  is coupled to a local oscillator  1204  that down mixes the received RF signal from radio frequency to an intermediate frequency. The intermediate frequency signal is band pass filtered in filter  1206  and then coupled to an RSSI detector  1208  which determines the RSSI level and provides an RSSI signal level. The intermediate frequency is also coupled to an active noise circuit  1210  and to a data detect circuit  1212 . 
     Data detect circuit  1212  includes an envelope detector  1214  an output of which is coupled to a summing amplifier  1216 . A second input of the summing amplifier  1216  is coupled to a threshold generator  1218  which has an adjustable threshold setting  1220 . Envelope detector  1214  further includes a byte detect line  1222 . The output data is squared up through comparator  1224  and passed through deglitcher  1226 . 
     Active noise circuit  1210  includes a noise subtraction switch  1228  coupled to a noise subtract control line  1238 . Circuit  1210  includes a noise integrator  1230  which is coupled to a summing amplifier  1232  that has a second input coupled to an output of a threshold generator  1234  and thus to an adjustable noise threshold  1236 . An output of the summing amplifier  1232  is coupled through a comparator  1240  and passed through deglitcher  1242  to provide noise signal level. Operation of demodulator  712  to detect data, RSSI level and noise level is illustrated in FIG.  31 . 
     The invention has been described in terms of several preferred embodiments. These descriptions should not, however, be taken as limiting as those of skill in the art will appreciate that the invention may otherwise be embodied without departing from the fair scope and spirit thereof. For example, the invention may be embodied in a system wherein equipment or devices, each including a badge constructed in accordance with the preferred embodiments of the invention, are matched with device users or other devices. The invention may also be embodied in a system apart from the described hospital environment without departing from its fair scope.