Abstract:
There is disclosed an animal identification, feeding and entry control system based on a radio frequency identification (RFID) system including an animal collar-mounted RFID tag, and RFID circuitry including a single antenna housed within a bezel placed forward of and surrounding the entry aperture to optimize signal reception. The bezel shape allows only one animal to enter at a time. To conserve power, the circuitry is only activated when an animal pushes against a door within the device, triggering a switch mechanism. A circuit-controlled latch prevents animals from opening the door unless a code match is detected between the programmed code in the tag and a stored code in the circuit controlling the system. Multiple codes may be stored for identifying multiple animals wearing collars tagged with unique identifying codes. The system&#39;s applications include but are not limited to controlling animal entry to feeding enclosures, human housing and animal housing.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   Animal identification and entry control system application Ser. No. 11/123,583. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   N/A 
   BACKGROUND 
   The present invention relates generally to animal entry systems, and more specifically to a radio frequency identification (RFID) based system for controlling pet access to specific doorways and enclosed structures, particularly animal feeders. It would be generally desirable for animal feeders to have the capability to recognize and allow entry to specific animals and also to deny entry to all other animals. It would also be generally desirable for these entry systems to be easily taught or programmed to recognize specific animals, and to then operate independently, safely and reliably without the need for frequent maintenance including battery changes. 
   There are numerous pet access control systems in existence, many of which are capable of identifying one or more specific animals. Some of these access control systems identify the specific animals by using radio signals sent to and from suitably constructed identification collars, while others use identifying means including magnets or infra-red transmitters embedded in animal collars. 
   The non-radio-based animal identification systems uniformly suffer from range and orientation problems, where the magnetic based systems must have the magnet extremely close to the sensor to work. Infra-red systems require a clear line-of-sight, thus making reliable operation of infra-red based animal identification systems difficult. 
   The older radio-based animal identification systems were based on purely analog circuitry, and many of these systems were designed to excite an analog resonant circuit element worn by an animal and to detect the analog signal resulting from the excitation of this element. This type of circuit was dependent on the tuning of an oscillator and the tuning of the resonant element, and was also very sensitive to antenna orientation and distance, and as such was not robust. Aside from the difficulties in maintaining sufficient tuning accuracy, these systems required much more complex tuned circuitry in order to identify multiple specific animals. The circuits also were generally designed to run continuously, and as such were very power-inefficient. 
   One example of a purely analog circuit-based animal identification and entry control system is taught by U.S. Pat. No. 4,497,133 filed Feb. 5, 1995 entitled PET DOOR WITH CONTROL CIRCUIT THEREFOR which discloses a pet door with a control circuit whose ability to recognize a passive radio frequency ID element depends on the use of a specific resistor in the circuit. This resistor is sold along with the ID element that is used as a key tag worn by the pet. The requirement to install one specific resistor in the circuit to enable a specific oscillator frequency is a very limiting approach. This invention has no programmability other than by replacing circuit components, and no ability to recognize multiple ID elements. The invention does use a switch connected to the door to turn on the circuit when the door is pressed by an animal, thus providing operation only when necessary. 
   British Patent No. GB 2,305,211 filed Apr. 2, 1997 entitled Security Locking Circuit discloses a security locking circuit suitable for use with a door latch, with a passive tuned circuit functioning as the key responding to a release signal. The control system is based on a microprocessor and has the ability to learn and recognize multiple individual tuned circuits functioning as ID elements. The means for ID element characterization is dependent on the circuit characterizing and storing whatever resonant signal the ID element generates in response to the transmitted signal. This is a risky method, since there is no control on how well any one specific response signal can be differentiated from the signals generated by other tuned circuits functioning as ID elements. The invention does include power savings through the option of a sleep mode, where an animal pushing against the door would operate a microswitch that would turn the circuit on. 
   U.S. Pat. No. 5,992,096 filed Nov. 30, 1999 entitled CONTROLLABLE PET ACCESS SYSTEM teaches a controllable pet access system that uses one or more solenoids to unlock a pet door in response to a reader circuit scanning and receiving a signal from a passive ID element described only as an “encoded animal tag” or “encoded pet tag”. This invention uses a motion detector to activate the reader circuit, thus requiring constant power for the motion detector. The invention is also lacking programmability or means to identify multiple ID elements. 
   The most common application for both the radio and non-radio-based animal identification systems is for animal feeders. The majority of the inventions in this field have been for use with livestock, where there are strong economic incentives for controlling feed distribution to each animal in a pasture or similar environment. Pet feeders are a smaller portion of this inventive field, with the primary motivation being convenience. 
   U.S. Pat. No. 3,465,724 filed Sep. 9, 1969 entitled RECORDING AND/OR CONTROL OF THE FEEDING OF LIVESTOCK and U.S. Pat. No. 3,557,758 filed Jan. 26, 1971 entitled ANIMAL IDENTIFICATION AND CONTROL MEANS both disclose feeding enclosures with access controlled by the interaction of an animal-carried passive tuned circuit ID element with a transformer-type oscillator circuit. Both of these inventions include the output and detection of multiple frequencies to allow for a group of individual ID elements. Both of these inventions use as ID elements tuned analog circuits that must match the output frequencies of the oscillator circuit, and further the location of the ID element on the body of the animal and in relation to the transmitting and receiving coils is critical to the proper function of each of these inventions. These inventions are not turned on by an animal interacting with them but run constantly, and are thus power-inefficient. 
   U.S. Pat. No. 3,897,753 filed Aug. 5, 1975 entitled MEANS AND METHOD FOR SELECTIVELY CONTROLLING ANIMALS discloses an animal feeder and entry control system which in the primarily illustrated embodiments are intended for use with domestic animals, particularly pet cats. This invention does include both a food dispenser (but not food enclosure) and an enclosure door unlocking function among its embodiments. However, the driver circuit taught by this invention depends on a tuned element&#39;s effect on what are effectively the coils of a transformer to produce a change in output and thus identify a specific ID element carried by an animal. The location of the ID element in relation to the receiving coil is critical to the proper function of this invention, but there is no explicit location control taught. Additionally, this invention runs constantly, and thus is power-inefficient. This invention does not teach the use of a microprocessor or other digital device to control frequency generation or other system functions, but does teach the use of multiple ID elements responding to individual excitation frequencies. 
   U.S. Pat. No. 4,036,178 filed Jul. 19, 1977 entitled ELECTRONIC LOCK AND KEY SYSTEM, a continuation-in-part of U.S. Pat. No. 3,897,753, teaches a more generalized approach to an entry control system, but uses the same inefficient signal generation and detection techniques as the parent patent. 
   British Patent No. 1,577,023 filed Oct. 15, 1980 entitled APPARATUS FOR CONTROLLING DISPENSING OF FEED TO ANIMALS discloses the use of multiple passive radio frequency ID elements to enable the controlled feeding of multiple animals, but uses numerous feeding stations controlled through a central location. 
   U.S. Pat. No. 4,463,706 filed Aug. 7, 1984 entitled METHOD AND SYSTEM FOR MONITORING THE DISPENSING OF DRUGS OR NUTRIENTS TO ANIMALS discloses the use of passive radio frequency ID elements carried by the animals to identify individual animals. The ID element contains memory and countdown timer circuitry that is updated by a base radio unit with information as needed. However, much of the circuitry in the animal-carried portion of this invention is actually powered by a battery. 
   U.S. Pat. No. 4,532,892 filed Aug. 6, 1985 entitled ANIMAL FEEDING AND MONITORING SYSTEM discloses an invention where the element worn by the animal is more than simply a passive radio frequency identification device; it is powered by the electromagnetic signals emitted by the base unit and contains code generating circuitry. This invention also has a control unit that runs continuously, thereby being wasteful of power and a poor choice to be run from batteries. 
   U.S. Pat. No. 5,309,864 filed May 10, 1994 entitled METHOD AND APPARATUS FOR FEEDING ANIMALS and U.S. Pat. No. 5,740,757 filed Apr. 21, 1998 entitled METHOD AND APPARATUS FOR FEEDING ANIMALS both disclose inventions that use multiple passive radio frequency ID tags to enable the controlled feeding of multiple animals, but both of these inventions have control and frequency generation circuitry that run continuously. 
   U.S. Pat. No. 6,044,795 filed Apr. 4, 2000 entitled AUTOMATIC FEEDING SYSTEM HAVING ANIMAL CARRIED TRANSMITTER WHICH TRANSMITS FEEDING INSTRUCTIONS TO FEEDER discloses a pet food dispenser using a passive radio frequency ID element worn by the animal. However, this invention lacks any feeding enclosure or any sort of sleep or power-off mode to conserve power. Further, this invention does not offer any user programmability for accepting different ID elements, or the ability to separately identify multiple animals. 
   U.S. Pat. No. 6,349,671 filed Feb. 6, 2002 entitled PET FEEDING SYSTEM AND METHOD OF USING SAME discloses a pet feeder that uses a passive radio frequency ID element worn by the animal, and that has the ability to identify multiple ID elements worn by multiple animals. However, the food covers are motorized, and the device is continually on. Thus, the invention suffers from both continual battery drain and higher battery use requirements for the motors. 
   A significant improvement over the existing art would be an animal identification and entry control system that could accurately detect multiple specific animals and could be easily and quickly programmed to recognize other animals when necessary, was powered by batteries and only drew battery power when absolutely necessary, used low-power circuitry for a minimum of battery power drain when in active operation, was durable and weatherproof enough to be used outdoors, was capable of safely limiting access to a single animal at a time, would keep any supply of food and water both fresh and inaccessible to other animals, and was adaptable to entry control for applications including but not limited to entry to a feeding enclosure, entry to a human dwelling, and entry to an animal dwelling. 
   SUMMARY 
   In accordance with the present invention, an RFID-based animal identification and entry control system is disclosed. This system is designed to be adaptable to any entry control application suitable for small to medium-sized animals, and is particularly well suited for use with domestic feline cats and small dogs. 
   The RFID portion of the system uses an RFID tag element suitable for use as a collar tag that may be attached to a regular animal collar. Each separate tag element can be programmed with a unique code, and multiple codes may be programmed, stored and recognized by the RFID system. The means for programming included in the RFID portion of the system is designed to allow the rapid and simple teaching of multiple tag codes. 
   The RFID means used in the system described hereinafter includes a commercially available digital RFID system including the collar tag elements, each with an individual digital code programmed into the internal memory. A typical system of this type is the Texas Instruments Series 2000 Reader System, which is the preferred system for use with the present invention. Other typical control circuitry preferred for use with this invention includes a microcontroller such as the PIC16F876. The techniques of circuit design, antenna design, printed circuit board layout, integration, programming and general use of the RFID circuitry including the commercially available RFID system, microcontroller and other circuitry disclosed herein are well known to those skilled in the art. 
   The preferred means for RFID also consists of signal processing circuitry for initial processing of the incoming signal, a door control circuit including a sensing switch, a latch and a solenoid with driver circuitry, and the single antenna coil. 
   The means for allowing and denying access is a lockable door, configured to block an aperture formed as an animal-sized opening in a boundary surface such as a feeding enclosure, fence, wall or larger door. The preferred means for locking and unlocking the door and thus allowing an animal to pass through is a latch mechanism actuated by a solenoid operated by the control circuitry. The door is located at the end of an entryway defined by a bezel preferably dimensioned to allow only a single animal to enter at a time. The passage length of the bezel and thus of the entryway is preferably no greater than the body length of the general size of animal that the feeder is designed to accomodate. The first end of the entryway is at the aperture, and the second end of the entryway is where an animal initially enters the bezel. In the preferred embodiment, when the door is allowed to open, it does so by swinging upwards and inwards from pivots located at or near the top edge of the door. When the animal that has entered the entryway presses against the outer surface of the locked door, a switch connected to the door is activated, and this in turn serves to turn on the control circuit. This causes the circuitry to generate a signal through the antenna coil that will activate an appropriate RFID tag element if such is within range of the system, causing such an element to send an identifying return signal to be received by the antenna coil. 
   The antenna coil is preferably located in the bezel that surrounds the entryway, and is preferably shaped into a loop that encircles the inside of the bezel at some distance forward of the door. This serves to create an ideal location relationship between the RFID tag element and the antenna coil at the time when signals are most likely to be transmitted to the tag and then from the tag to the antenna coil. This loop is not necessarily round in shape, but it does need to be wider than both the aperture and the door, and fit inside the confines of the bezel. 
   If the return signal generated by the RFID tag element and then received by the antenna coil should match with one of the codes stored in the RFID circuitry, the door control circuit will be activated and the solenoid will open the door latch and allow the animal to push the door open and pass through the doorway. As soon as the animal has ceased pushing the door open, the door will pivot shut and latch closed again, preventing any other animals from entering unless they also possess a collar with a recognized RFID tag. 
   The power source for this entry control system is preferably batteries, but may also be a pluggable DC adapter or direct attachment to the local AC power. 
   In addition to the basic door function that may be used to control animal entry to a feeding enclosure, the door function may be adapted to other purposes including to control animal entry to or through an animal habitation, a human habitation, or any boundary surface such as a wall, fence or door. 
   The door function is preferably adapted to control entry to an enclosed feeding chamber by having the bezel be configured to surround an opening in the feeding chamber walls. The preferred design of feeding chamber also will not allow the animal to fully enter, thus preventing any chance of the animal becoming trapped within the feeding chamber if the door closes. 
   For the door function to work in the best mode with an animal feeder, it is preferable for the animal feeder to operate autonomously with batteries as a power source, thus requiring electronics that have a very low power draw and using power consumption strategies that minimize the length of time when any significant amount of power will actually be drawn. The majority of the RFID circuitry is kept in a default state of minimum-power sleep mode, with a switch connected to the door signaling the circuitry to wake up into active mode when pressure against the door closes the switch contact. After a predetermined length of time without any switch closure, the circuitry will return to sleep mode, thus prolonging battery life. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     A more complete understanding of the invention and its advantages will be apparent from the detailed description taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is a perspective view of the animal feeder; 
       FIG. 2  is a section side view of the feeder; 
       FIG. 3  is a flowchart of circuit function and system operation; 
       FIG. 4  is a block diagram of the circuit including the control and signal circuitry; 
       FIG. 5  is a detailed view of the animal collar and the attached RFID tag; 
       FIG. 6  is an exploded perspective view of the animal feeder&#39;s main mechanical parts; 
       FIG. 7  is a perspective view of the feeder showing a cat entering; 
       FIG. 8  is a perspective view of the feeder showing a cat feeding and a second cat excluded. 
   

   DETAILED DESCRIPTION 
   An animal identification and entry control system is provided that permits selected animals to gain entrance through a specific doorway, and bars entry to other animals. The presently disclosed entry control system may be used to control entrance to places including but not limited to an animal feeder, an animal habitation or a human habitation. 
     FIG. 1  depicts an illustrative embodiment of an animal feeder  5 , in accordance with the present invention.  FIG. 7  depicts an animal  97  entering the animal feeder  5 , and  FIG. 8  depicts an animal feeding  98  while an animal excluded stands outside the animal feeder  5 . The animal feeder  5  has a feeding chamber enclosure  70  with a bezel  10  defining an entryway  19 . In the preferred embodiment the bezel outer walls  11  form a continuous surface with the chamber enclosure walls  71 , chamber enclosure top  73  and chamber enclosure base  74 . The bezel fascia  15  preferably defines the contour of the entryway  19 , and the bezel inner walls  12  including the bezel ramp  14  as a floor surface and the bezel roof  13  (as shown in  FIG. 2 ) define the overall dimensions of the preferred embodiment of the entryway  19 . The back of the entryway  19  is bounded by the bezel secondary ramp  76  and the door  20 . The location of the door  20  thus defines the passage length of the bezel  20  and the entryway  19 . As seen in  FIG. 7 , this passage length is preferably at least sufficient to allow the head and shoulders of one animal  97  to be inside the entryway  19  before the door  20  is opened. In the preferred embodiment the door  20  is angled inwards down from the door pivot  23  towards the feeding chamber enclosure  70  to require less travel when opening and to have a more positive closure than would be gained from hanging vertically. Other door attachment and hinging mechanisms may be employed, but the use of gravity to close the door  20  produces a simple and economical mechanism. Alternative mechanisms using one or more springs may also be employed to yield a more forceful closure. The door  20  also includes a curved door bottom  78  and airholes  82 , and is secured to the bezel  10  by a door retainer  80  in a manner that permits the door pivot  23  to serve as a hinge, such that the door  20  will swing upwardly and inwardly when pressed upon by an animal  97  in the entryway  19 . The airholes  82  permit the odor of any contents of the food pan  88  to propagate outwards from the animal feeder  5  to attract the animal  97 . The airholes  82  are preferably located in the door  20  to attract the animal  97  to the outward surface of the door  20 . 
   The preferred embodiment door  20  is shaped with the curved door bottom  78  to prevent any portion of the collar  50  from catching on or becoming entangled in any portion of the door  20 . The curved door bottom  78  will preferably rest on the shoulders or back of the animal feeding  98  when the animal feeder  5  has been successfully entered. It is preferable for the dimensions of the feeding chamber enclosure  70  to orient the animal feeding  98  to have a portion of the door  20  resting on the animal&#39;s shoulders so that the animal feeding  98  is most fully blocking the entryway  19 . The preferred curvature of the curved door bottom  78  is between 18 mm and 65 mm radius, with an arc section of between 30 degrees and 75 degrees. Optionally, the door  20  may be made of transparent material so that the animal  97  may see into the feeding chamber enclosure  70  before pressing against the door  20 . 
   The preferred embodiment of the animal feeder  5  has the feeding chamber enclosure  70  formed as a single chamber as shown in  FIG. 2  and dimensioned to prevent animals from completely entering the feeding chamber enclosure  70  and thus possibly becoming trapped if the door  20  closes behind them. Such an animal feeding is shown in  FIG. 8 . with only the front portion of the animal in the feeding chamber. The animal feeder  5  is preferably designed to be used by domestic feline cats or small dogs of between 2 kilos and 10 kilos weight, where weight is used as an approximation of overall animal size. A larger version of the system can be built for animals over 20 kilos such as medium-sized dogs. 
   The bezel  10  is preferably dimensioned such that only one animal  97  in the intended size range can fit inside the entryway  19  at once. The bezel  10  also limits the animal&#39;s angle of approach to the feeding chamber enclosure  70 , making it more difficult for a second animal to try to squeeze in beside the animal feeding  98 , as shown in  FIG. 8 . where there is an animal feeding  98  and an animal excluded  99 . In the preferred embodiment, the animal  97  is wearing a collar  50 , preferably of a standard animal collar band  51  style with a collar fastener  52  for ease of attachment and removal, and an RFID tag element  54 , preferably attached with an RFID tag fastener  53  as illustrated in  FIG. 5 . If the animal  97  enters the bezel  10  and presses against the door  20 , the resulting movement of the door  20  before being stopped by the door latch  38  causes closure of the door switch  36 , located inside the bezel  10 . This door switch  36  actuation triggers the “GO” input shown in  FIG. 3 , the flowchart of control board  30  containing control circuitry  29 , and related component function. 
   The system response to a door switch  36  closure is initially to activate and awaken the microcontroller  62  shown in  FIG. 4  into the active state. The preferred first action by the awakened microcontroller  62  is to check the level of the batteries  32  using the circuit element DC Converter &amp; Low Battery Comparator  47 , which if the voltage of the batteries  32  is above the set Low Battery threshold, leads to checking the door  20  status. If the door  20  is still being pressed upon and thus the switch  36  is still activated, then the microcontroller  62  will instruct the RFID Module  64  to produce an interrogation signal that will be sent through the antenna connector  42  to be broadcast by the antenna coil  31 . The combination of functions provided by the microcontroller  62 , the RFID module  64  and the circuitry enabling them to function together provide the RFID sensor means required for the system. 
   If the animal  97  pressing against the door  20  is wearing a collar  50  with an RFID tag element  54 , then the RFID antenna  56  will receive the interrogation signal and the interrogation signal will supply power to the RFID circuitry  58  and will be processed by the RFID tag circuitry  58  in such a fashion as to trigger a digital code output from an onboard memory register. The RFID tag circuitry  58  will then transmit this digital code back through the RFID antenna  56 . 
   If the animal  97  is within the bezel  10  when the digital code is transmitted, then the antenna coil  31  will receive the digital code and transmit the digital code through the antenna connector  42  to the RFID module  64 , where it will be compared with programmed codes stored in the RFID module  64  memory. If there is a match between a stored code and the digital code received from the RFID tag element  54 , then the RFID module  64  will signal the microcontroller  62  to activate the solenoid drive circuitry  45  and through the solenoid connector  46  activate the solenoid  39  to unlock the door latch  38  and thus allow the animal  97  to push the door  20  open. The microcontroller  62  and related circuitry contain a means for timekeeping, and after some programmed time increment, the microcontroller  62  will deactivate the solenoid drive circuitry and through the solenoid connector  46  deactivate the solenoid  39  and thus lock the door latch so that if the door is in the shut position or when the door is returned to the shut position, it will re-lock. If there is then no closure detected of the door switch  36 , the microcontroller  62  and the RFID module  64  will return to a sleep state and then to Deep Sleep as labeled in the flowchart of  FIG. 3 , this default operational state drawing a nonzero but minimum amount of power and thus maximizing the conservation of battery life. 
   If the DC Converter &amp; Low Battery Comparator  47  measures battery voltage below the Low Battery Threshold, a Low Battery LED  44  will flash periodically, thus alerting the need to change the batteries  32 . The batteries  32  are held in a battery holder  33  that is preferably secured within the chamber enclosure base  74  and accessed through the battery lid  34 . The batteries  32  are electrically connected to the circuitry of the control board  30  through the battery connector  35 . Alternatively, the animal feeder may be powered from household AC, using a DC converter, or may be direct-wired into the household AC wiring, with appropriate onboard power conversion circuitry. Appropriate supply voltages for the microcontroller  62 , the RFID module  64  and the other circuitry are provided through the voltage regulator  43 . 
   The preferred embodiment animal feeder  5  contains a food pan  88  designed to hold any appropriate type of nutritional materials such as food or water, located within a food pan recess  86  formed into the chamber enclosure base  74 . The preferred embodiment feeding chamber enclosure  70  is molded of plastic material and is removably snapfitted onto the chamber enclosure base  74 , also preferably molded of plastic material. Snapfits function here as a cost-effective form of mechanical latch. The male snapfits  83  as shown in  FIG. 6  are preferably formed into the body of the feeding chamber enclosure  70 , and the female snapfits  87  are preferably formed into the body of the chamber enclosure base  74 . The food pan  88  is preferably formed of a durable, cleanable and food-safe material such as stainless steel, and is designed to be easily removed from the food pan recess  86  for cleaning and filling. Side handles  72  are preferably formed into the chamber enclosure walls  71  both to aid in removing the feeding chamber enclosure  70  from the chamber enclosure base  74  and to aid in lifting and moving the entire assembled animal feeder  5 . There is preferably an open space below the food pan  88  within the food pan recess  86 , into which can be placed cooling means for the food contents of the food pan  88 . For use outdoors, the animal feeder  5  may include fastening mounts and hardware that allow it to be fastened to the ground or other underlying surfaces. Alternatively, the animal feeder may be equipped with rubber feet or other high-friction means to prevent movement when pressed against by an animal or other external force, either indoors or outdoors. 
   The chamber enclosure top portion  73  in the preferred embodiment serves as a roof and has a top opening  85  into which a skylight  84  preferably formed of transparent or translucent plastic may be fitted. The skylight  84  permits light to enter the feeding chamber enclosure  70 , and facilitates viewing the contents and interior of the feeding chamber enclosure  70 . 
     FIG. 8  shows the animal feeder  5  with an animal feeding  98  located inside the bezel  10  and the feeding chamber enclosure  70 , and an animal excluded  99  located outside the animal feeder  5  and unable to gain entry due to the location of the animal feeding  98  and the shape of the bezel  10  and the entryway  19 . 
   The unique identification codes of one or more RFID tag elements  54  may be programmed into the control circuitry  29  for recognition. An RFID tag element  54  is held near the antenna coil  31  and the programming button  37  is pressed. This procedure may be repeated for as many RFID tag elements  54  as the RFID module  64  and the microcontroller  62  are capable of recognizing. 
   In addition to the entry control functions described above, there are other functions that can be programmed into the control circuitry  29 . One optional function is a timer implemented in either hardware, software or a combination of both, that is designed to be programmed by the animal owner to only allow access to the feeder during set times, where different set permitted entry times can be programmed for each different animal wearing an RFID tag element. Optionally, this timer function may be used in place of the RFID sensing system as a method of controlling entry to the feeder. 
   Another optional function allows the storage and display of access information, thus enabling the animal owner to have a record of when and how often the door switch  36  has been actuated, how often each animal has accessed the feeder, and how long each animal spent in each feeding session. 
   Yet another optional function allows the animal feeder  5  to be programmed to only allow a set number of accesses for each recognized RFID tag element  54  per day. 
   An alternate method of securing the RFID tag element  54  to an animal is to use well-known permanent physical attachments including but not limited to ear tags. A further alternate method of securing the RFID tag element  54  to an animal is to implant the RFID tag element  54  within the body of an animal. 
   An alternate embodiment of the door switch  36  is located beneath a portion of the bezel ramp  14  or bezel secondary ramp  76 , the ramps effectively serving as a bezel floor, and the switch is configured to actuate from the weight of an animal treading upon the floor surface. 
   An alternate embodiment of the animal feeder has the feeding enclosure manufactured as a unitary structure with no base included. This version would still have the feeding chamber dimensioned to prevent complete entry by an animal, and the bezel and entryway dimensioned to restrict access to a single animal at a time. 
   Another alternate embodiment of the animal feeder includes a storage container for a supply of animal food, preferably at least one day&#39;s worth, and a dispensing mechanism for dispensing the food from the storage container into the feeding chamber at set intervals of time, or when a sensor indicates that replenishing is needed. A preferred method for controlling the dispensing mechanism would have the time intervals and control signals originate in the control circuitry. 
   Yet another alternate embodiment of the animal feeder has no electronics, and is merely a feeding enclosure with an entry bezel shaped to restrict access to a single animal at a time and to prevent complete entry by the animal, thus preventing the animal from either becoming trapped or using the feeding enclosure as a hiding place. This version may be made with or without the pivoting door with air holes and a curved bottom section. 
   Further alternate embodiments of the RFID-enabled animal identification and entry control invention may be used to control entrance to locations other than animal feeders. For example, an embodiment of the invention could be used to control entry to an animal habitation or to a human habitation, or could be used for controlling passage through any boundary surface such as a wall, fence or door. 
   Having described herein illustrative embodiments of the present invention, persons of ordinary skill in the art will appreciate various other features and advantages of the invention apart from those specifically described above. It should therefore be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications and additions can be made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, the appended claims shall not be limited by the particular features that have been shown and described, but shall be construed also to cover any obvious modifications and equivalents thereof.