Abstract: A pet monitoring device (101) for monitoring a sub-dermal RFID microchip (103), the pet monitoring device comprising: a wearable item (1) bearing 1 to 5 turns of electrical conductor (7) wound circumferentially to form a wearable item resonator; and an RFID reader (9) attachable and detachable to said wearable item, wherein said RFID reader comprises: a driving circuit (1100) comprising a primary inductance (Lp) inductively coupled to said wearable item when said RFID reader is attached to said wearable item; a secondary inductance (Ls) and resonance capacitor (Cs) conductively coupled to said wearable item when said RFID reader is attached to said wearable item, wherein the secondary inductance and resonance capacitor form the wearable item resonator with said electrical conductor, wherein the wearable item resonator comprises a circuit (1004) to automatically adjust said resonance capacitor to compensate for a size of said wearable item when fitted to said pet; wherein the driving circuit is operable to dri

Abstract: This invention general relates to animal feeders, an animal feeding monitor and a method of training an animal to use a feeder. An animal feeder may have a housing comprising an aperture for a food bowl (8) and having a door for covering the aperture, the feeder comprising a door mechanism to control movement of the door over the aperture, wherein the feeder comprises a sensor to detect when an animal has moved away from the aperture, and the feeder is configured to be operable in a training mode wherein the door mechanism is operable to control the door to cover a portion of the aperture in response to a said detection and to respond to one or more later said detections by controlling the door to cover a portion of the aperture larger than the preceding said portion.

Abstract: This invention general relates to animal feeders, an animal feeding monitor and a method of training an animal to use a feeder. An animal feeder may have a housing comprising an aperture for a food bowl (8) and having a door for covering the aperture, the feeder comprising a door mechanism to control movement of the door over the aperture, wherein the feeder comprises a sensor to detect when an animal has moved away from the aperture, and the feeder is configured to be operable in a training mode wherein the door mechanism is operable to control the door to cover a portion of the aperture in response to a said detection and to respond to one or more later said detections by controlling the door to cover a portion of the aperture larger than the preceding said portion.

Abstract: This invention generally relates to animal feeders, an animal feeding monitor and a method of training an animal to use a feeder. An animal feeder may have a housing with an aperture for a food bowl and a door for covering the aperture. The feeder can further include a door mechanism to control movement of the door over the aperture and a sensor to detect when an animal has moved away from the aperture. The feeder is configured to be operable in a training mode wherein the door mechanism is operable to control the door to cover a portion of the aperture in response to the detection and to respond to one or more later detections by controlling the door to cover a portion of the aperture larger than the preceding portion.

Abstract: A pet monitoring device (101) for monitoring a sub-dermal RFID microchip (103), the pet monitoring device comprising: a wearable item (1) bearing 1 to 5 turns of electrical conductor (7) wound circumferentially to form a wearable item resonator; and an RFID reader (9) attachable and detachable to said wearable item, wherein said RFID reader comprises: a driving circuit (1100) comprising a primary inductance (Lp) inductively coupled to said wearable item when said RFID reader is attached to said wearable item; a secondary inductance (Ls) and resonance capacitor (Cs) conductively coupled to said wearable item when said RFID reader is attached to said wearable item, wherein the secondary inductance and resonance capacitor form the wearable item resonator with said electrical conductor, wherein the wearable item resonator comprises a circuit (1004) to automatically adjust said resonance capacitor to compensate for a size of said wearable item when fitted to said pet; wherein the driving circuit is operable to dri

Abstract: We describe an animal entry control system, for example for a cat flap, using RFID (radio frequency identification). The system comprises an RFID reader to register the presence and identification number of a transponder (15) injected under the skin of an animal; and a door (8) mounted on a hinge (10) and controlled by the RFID tag reader. The RFID reader comprises a resonant circuit including a tuning circuit to control the RFID reader such that a drive frequency of the RFID reader matches both a resonant frequency of the RFID reader and a resonant frequency of the transponder. Embodiments of the system are thus tolerant to a degree of detuning, for example from a metallic or magnetic material in the vicinity of the antenna.

Abstract: An RF tag for sending data to a tag reader is described. The tag comprises an antenna to couple to an RF field of the tag reader and first and second resonant circuits, the first comprising a non-linear, adaptive resonator configured to automatically self-tune to a frequency of the RF field, the second a linear resonator. The tag also has a local power store. The tag powers up using the non-linear, adaptive resonator, which can automatically self-tune without an external power supply, and this resonator is used to charge the local power store. Once operational the tag switches to using a linear resonator for communicating with the tag reader.

Abstract: An RFID reader for use in a pet door to control access for a pet bearing an RFID tag or implant. The RFID reader incorporates and is operable in two modes, a learn mode and a normal mode. In learn mode, the reader stores the ID code of an RFID transponder in the vicinity of the reader and also derives additional reader information corresponding to the RFID transponder. In normal mode, the reader compares the ID codes stored in memory to the RFID signal returned from an RFID transponder in the vicinity of said the reader. The RFID reader behavior is at least in part determined by the additional reader information corresponding to said ID codes stored in memory. We also describe a confidence threshold for acceptance of an ID code in learn mode and normal mode. The confidence threshold in normal mode may be less than in learn mode.

Abstract: We describe an animal entry control system, for example for a cat flap, using RFID (radio frequency identification). The system comprises an RFID reader to register the presence and identification number of a transponder (15) injected under the skin of an animal; and a door (8) mounted on a hinge (10) and controlled by the RFID tag reader. The RFID reader comprises a resonant circuit including a tuning circuit to control the RFID reader such that a drive frequency of the RFID reader matches both a resonant frequency of the RFID reader and a resonant frequency of the transponder. Embodiments of the system are thus tolerant to a degree of detuning, for example from a metallic or magnetic material in the vicinity of the antenna.

Abstract: Embodiments of the invention relate to the field of RFID (radio frequency identification). Some particularly preferred embodiments relate to a high-Q, so-called “full duplex” (FDX) RFID Reader. An RFID tag reader, the reader comprising: an electromagnetic (EM) field generator for generating an electromagnetic (EM) field for modulation by said tag, said modulation comprising modulated load of said EM field by said tag; a detector system responsive to fluctuations in strength of said EM field at said reader; a negative feedback system responsive to said detector system to provide a control signal for said EM field generator for controlling said EM field generator to reduce said detected fluctuations; and a demodulator responsive to said control of said EM field to demodulate said EM field modulation by said tag.

Abstract: An animal feeding monitor and a method of training an animal to use a feeder.

Abstract: An RF tag for sending data to a tag reader is described. The tag comprises an antenna to couple to an RF field of the tag reader and first and second resonant circuits, the first comprising a non-linear, adaptive resonator configured to automatically self-tune to a frequency of the RF field, the second a linear resonator. The tag also has a local power store. The tag powers up using the non-linear, adaptive resonator, which can automatically self-tune without an external power supply, and this resonator is used to charge the local power store. Once operational the tag switches to using a linear resonator for communicating with the tag reader.

Abstract: Embodiments of the invention relate to the field of RFID (radio frequency identification). Some particularly preferred embodiments relate to a high-Q, so-called “full duplex” (FDX) RFID Reader. An RFID tag reader, the reader comprising: an electromagnetic (EM) field generator for generating an electromagnetic (EM) field for modulation by said tag, said modulation comprising modulated load of said EM field by said tag; a detector system responsive to fluctuations in strength of said EM field at said reader; a negative feedback system responsive to said detector system to provide a control signal for said EM field generator for controlling said EM field generator to reduce said detected fluctuations; and a demodulator responsive to said control of said EM field to demodulate said EM field modulation by said tag.

Abstract: We describe RFID tags that incorporate a nonlinear resonator that self-adapts to the driving frequency of a reader. More particularly we describe an RF tag for sending data to a tag reader by modulating energy drawn from an RF field of said tag reader, the tag comprising: an antenna; a resonant circuit coupled to said antenna to resonate at a frequency of said RF field; a local power store to store power extracted from said RF field; a modulation system to modulate one or both of the resonance amplitude and a relative phase of a signal in said resonant circuit with respect to said RF field; and a feedback circuit coupled to said resonant circuit and to said local power store to control one or both of said resonance amplitude and said relative phase to control transients in said resonance amplitude caused by said modulation.

Abstract: Embodiments of the invention relate to the field of RFID (radio frequency identification). Some particularly preferred embodiments relate to a high-Q, so-called “full duplex” (FDX) RFID Reader. An RFID tag reader, the reader comprising: an electromagnetic (em) field generator for generating an electromagnetic (em) field for modulation by said tag, said modulation comprising modulated load of said em field by said tag; a detector system responsive to fluctuations in strength of said em field at said reader; a negative feedback system responsive to said detector system to provide a control signal for said em field generator for controlling said em field generator to reduce said detected fluctuations; and a demodulator responsive to said control of said em field to demodulate said em field modulation by said tag.

Abstract: A circuit block which comprises a non-linear capacitor with two different values of capacitance dependent on a value of a voltage of a resonant signal on the capacitor; a plurality of second capacitors each coupled to a respective switch to enable a said second capacitor to be switched in or out of parallel connection with the nonlinear capacitor; and a tuning control, coupled to the second capacitor switches, and sensing an amplitude of the resonant signal. The tuning control circuit is configured to control the second capacitor switches to successively switch the second capacitors in/out of parallel connection with the non-linear capacitor dependent on the amplitude of the resonant signal until the non-linear capacitor has substantially a single one of two different values, such that in a resonant circuit the circuit block then behaves as a fixed value capacitor.

Abstract: Embodiments of the invention relate to the field of pet doors, particularly selective entry pet doors based on detection of RFID tags. An RFID pet door, the pet door comprising: an RFID reader to read an RFID tag on a pet; and a lock coupled to said RFID reader to control access through said pet door in response to an RFID signal from said tag; wherein said RFID reader has two modes, a first operational mode and a second, reduced power mode, and wherein said pet door further comprises: a pet proximity detector coupled to said RFID reader to identify when a pet is proximate said pet door and to control said RFID reader responsive to said identification such that when said pet is proximate said RFID is in said operational mode and such that said RFID reader is otherwise in said reduced power mode.