Abstract: A method includes determining, by a processing module of a data logging device, whether an event has occurred that potentially compromises reliability of the data logging device. The method further includes, when the event has occurred, determining, by the processing module, whether the reliability of the data logging device has been compromised. The method further includes, when the reliability of the data logging device has been compromised, generating, by the processing module, a compromised indication signal. The method further includes, when the reliability of the data logging device has not been compromised, generating, by the processing module, a data integrity indication signal.

Abstract: A data logging device includes an activation circuit, an environmental sensor, a processing module, and an environmental indicator. The activation circuit is operably coupled to place the data logging device in a ready mode based on an activation signal. The environmental sensor is operable to sense an environmental condition associated with the data logging device in response to a log command to produce sensed data. The processing module is operably coupled to generate the log command; receive the sensed data; determine whether the sensed data triggers an environmental violation; and, when the sensed data triggers the environmental violation, generate an environmental violation signal. The environmental indicator is operably coupled to provide a visual indication of the environmental violation based the environmental violation signal.

Abstract: A method includes processing, by a processing module of a data logging device, a plurality of log commands. The processing of a log command of the plurality of log commands includes obtaining a measure of an environmental condition. The processing further includes updating a status of the environmental condition based on the measure of an environmental condition. The method further includes determining, by the processing module, the updated status of the environmental condition after the plurality of log commands have been processed. When the updated status of the environmental condition is favorable, the method further includes generating, by the processing module, a favorable environmental condition signal.

Abstract: A method includes obtaining, by a processing module of a data logging device, a log command. The method further includes determining, by the processing module, whether to enter a finished mode for the data logging device based on a data logging condition. When not in the finished mode and in response to the log command, the method further includes obtaining, by the processing module, a measure of an environmental condition. The method further includes determining, by the processing module, whether the measure of the environmental condition is within an expected range. When the measure of the environmental condition is not within the expected range, the method further includes generating, by the processing module, an environmental violation signal when triggered.

Abstract: A method includes establishing, by a data logging device, a sleep mode. The method further includes receiving, by a processing module of the data logging device, a second activation command that causes the data logging device to transition to a standby mode. The method further includes receiving, by the processing module, a third activation command that causes the data logging device to transition to a ready mode. The method further includes receiving, by the processing module, a fourth activation command that causes the data logging device to transition to a logging mode. In the logging mode, the method further includes obtaining, by the processing module, a log command. In response to the log command, the method further includes obtaining, by the processing module, a measure of an environmental condition. The method further includes storing the measure of the environmental condition in memory of the data logging device.

Abstract: The low maintenance speed bump is an elongated, rigid, solid body having an arcuate top surface and a flat base, angled grooves defined in the top surface, and a reflective material disposed within the grooves. The reflective material is disposed lower than the top surface of the speed bump to prevent contact between vehicles passing over the speed bump and the reflective material. In this manner, the reflective material is protected from damage by vehicle tires and the life of the reflective material is extended. Further, the angled grooves provide greater visibility of the reflective material to drivers approaching the speed bump.

Abstract: The low maintenance speed bump is an elongated, rigid, solid body having an arcuate top surface and a flat base, angled grooves defined in the top surface, and a reflective material disposed within the grooves. The reflective material is disposed lower than the top surface of the speed bump to prevent contact between vehicles passing over the speed bump and the reflective material. In this manner, the reflective material is protected from damage by vehicle tires and the life of the reflective material is extended. Further, the angled grooves provide greater visibility of the reflective material to drivers approaching the speed bump.

Abstract: A method includes varying, by a tuning module of a passive radio RFID sensor, a reactive component impedance coupled to the tuning module and an antenna of the passive RFID sensor in order to change a system impedance. The method further includes producing an impedance value representative of the reactive component's impedance. The method further includes storing, by a memory module of the passive RFID sensor, the impedance value, identification information corresponding to the antenna, and a timestamp corresponding to the impedance value. The method further includes communicating, by a wireless communication module of the passive RFID sensor, the impedance value, the identification information, and the timestamp to an RFID reader. When the impedance value, the identification information, and the timestamp indicate an unfavorable environmental condition, the method further includes generating, by the RFID reader, an alarm signal.

Abstract: A power harvesting circuit a p-channel circuit, an n-channel circuit, an AC capacitance circuit, and an output capacitance circuit. The p-channel circuit includes a first diode element and a first start-up current circuit operably coupled to increase start-up current of the first diode element. The n-channel circuit includes a second diode element and a second start-up current circuit operably coupled to increase start-up current of the second diode element. The AC coupling capacitance circuit is coupled to the p-channel circuit and the n-channel circuit. The output capacitance circuit is coupled to the p-channel circuit and the n-channel circuit.

Abstract: A method begins by a first radio frequency identification (RFID) sensor, that is associated with a first object element, receiving a first data request signal from an RFID reader and sending a first radio frequency (RF) signal that includes first data to the RFID reader in response to the first data request signal. The method continues with a second RFID sensor receiving a second data request signal from, and sending second data to, the RFID reader. The method continues with the RFID reader sending a representation of the first and second data to a data processing unit, which processes the representation of the first and second data to determine a first and second data point regarding first and second object elements. The method continues by the data processing unit processing the first and second data points to determine an environmental relationship between the first and second object elements.

Abstract: A power harvesting circuit, a rectifier circuit and a capacitor. The rectifier circuit includes a diode circuit and a diode voltage reduction circuit. The diode circuit passes a current when a received RF signal has a first polarity and to substantially blocks the current when the received RF signal has a second polarity. The diode voltage reduction circuit is operably coupled to reduce a voltage drop of the diode circuit. The capacitor is operably coupled to convert the rectified signal into a DC supply voltage.

Abstract: A method includes varying, by a tuning module of a passive radio RFID sensor, a reactive component impedance coupled to the tuning module and an antenna of the passive RFID sensor in order to change a system impedance. The method further includes producing an impedance value representative of the reactive component's impedance. The method further includes storing, by a memory module of the passive RFID sensor, the impedance value, identification information corresponding to the antenna, and a timestamp corresponding to the impedance value. The method further includes communicating, by a wireless communication module of the passive RFID sensor, the impedance value, the identification information, and the timestamp to an RFID reader. When the impedance value, the identification information, and the timestamp indicate an unfavorable environmental condition, the method further includes generating, by the RFID reader, an alarm signal.

Abstract: A passive radio frequency identification (RFID) sensor includes at least one antenna. The least one antenna has an antenna impedance operable to vary within an environment in which the antenna is placed. The RFID sensor further includes a processing module coupled to the antenna comprising a tuning module coupled to the antenna. The tuning module is operable to vary a reactive component impedance coupled to the antenna in order to change a system impedance, the system impedance includes the antenna impedance and the reactive component's impedance, to produce an impedance value representative of the reactive component's impedance. The RFID sensor further includes a memory module operable to store the impedance value representative of the reactive component's impedance, and a wireless communication module coupled to the processing module, operable to communicate with an RFID reader and to exchange the impedance value representative of the reactive component's impedance with the RFID reader.

Abstract: A method begins by a first radio frequency identification (RFID) sensor, that is associated with a first object element, receiving a first data request signal from an RFID reader and sending a first radio frequency (RF) signal that includes first data to the RFID reader in response to the first data request signal. The method continues with a second RFID sensor receiving a second data request signal from, and sending second data to, the RFID reader. The method continues with the RFID reader sending a representation of the first and second data to a data processing unit, which processes the representation of the first and second data to determine a first and second data point regarding first and second object elements. The method continues by the data processing unit processing the first and second data points to determine an environmental relationship between the first and second object elements.

Abstract: A power harvesting circuit, a rectifier circuit and a capacitor. The rectifier circuit includes a diode circuit and a diode voltage reduction circuit. The diode circuit passes a current when a received RF signal has a first polarity and to substantially blocks the current when the received RF signal has a second polarity. The diode voltage reduction circuit is operably coupled to reduce a voltage drop of the diode circuit. The capacitor is operably coupled to convert the rectified signal into a DC supply voltage.

Abstract: A power harvesting circuit a p-channel circuit, an n-channel circuit, an AC capacitance circuit, and an output capacitance circuit. The p-channel circuit includes a first diode element and a first start-up current circuit operably coupled to increase start-up current of the first diode element. The n-channel circuit includes a second diode element and a second start-up current circuit operably coupled to increase start-up current of the second diode element. The AC coupling capacitance circuit is coupled to the p-channel circuit and the n-channel circuit. The output capacitance circuit is coupled to the p-channel circuit and the n-channel circuit.

Abstract: A passive radio frequency identification (RFID) sensor is provided. This passive RFID sensor includes an inductive loop, a processing module, and a wireless communication module. The inductive loop has an inductive loop impedance that may vary with an environment in which the inductive loop is placed. The processing module couples to the inductive loop and has a tuning module that may vary a reactive component impedance coupled to the inductive loop in order to change a system impedance. The system impedance includes both the inductive loop impedance and the reactive component impedance. The tuning module then produces an impedance value representative of the reactive component impedance. A memory module may store the impedance value which may then later be communicated to an RFID reader via the wireless communication module.

Abstract: A power harvesting circuit a p-channel circuit, an n-channel circuit, an AC capacitance circuit, and an output capacitance circuit. The p-channel circuit includes a first diode element, a first diode voltage reduction circuit coupled to reduce a diode voltage of the first diode element, and a first start-up current circuit operably coupled to increase start-up current of the first diode element. The n-channel circuit includes a second diode element, a second diode voltage reduction circuit coupled to reduce a diode voltage of the second diode element, and a second start-up current circuit operably coupled to increase start-up current of the second diode element. The AC coupling capacitance circuit is coupled to the p-channel circuit and the n-channel circuit. The output capacitance circuit is coupled to the p-channel circuit and the n-channel circuit.

Abstract: A power harvesting circuit, a rectifier circuit and a capacitor. The rectifier circuit includes a diode circuit, a diode voltage reduction circuit, and a start up current circuit. The diode circuit passes a current when a received RF signal has a first polarity and to substantially blocks the current when the received RF signal has a second polarity. The diode voltage reduction circuit is operably coupled to reduce a voltage drop of the diode circuit. The start up current circuit operably coupled to reduce the start up current of the diode voltage reduction circuit and/or the diode circuit. The capacitor is operably coupled to convert the rectified signal into a DC supply voltage.

Abstract: A wireless sensor includes an antenna, a sensing element, a tuning circuit, a processing module, a reference circuit block, and a transmitter. The tuning circuit adjusts the RF front-end to compensation for a change in a characteristic of the RF front end caused by the sensing element. The reference circuit block generates a signal based on a low voltage low frequency input that corresponds to a second environmental condition. The processing module generates a first digital value based on the adjustment to the RF front-end, where the first digital value is a representation of the first environmental condition, and generate a second digital value based on the signal, where the second digital value is a representation of the second environmental condition. The transmitter generates the outbound RF signal that includes at least one of the first and second digital values.