Abstract: One aspect of the invention involves: periodically sampling a voltage of a battery and an ambient temperature in order to obtain a sample that includes a temperature value and a voltage value; saving each sample in a sample group; selecting a subset of the samples in the group, wherein the temperature value of each sample in the subset is lower than the temperature value of substantially all of the samples of the group other than the subset; and determining as a function of the voltage of at least one the sample in the subset whether the battery is subject to a low voltage condition.

Abstract: A tag can switch between first and second modes of operation, and consumes less power in the first mode. In the second mode, the tag can receive wireless signals having successive first and second portions. If the tag identifies a repetitive pattern of the wireless signals, the tag ignores the second portions of the signals. Otherwise the tag receives the second portions. In another embodiment, while in the second mode, the tag can receive wireless signals having successive first, second and third portions. The tag switches between the first and second modes at one rate until it detects the first portion, and then switches at a higher rate until it detects the second portion, and then stays in the second mode and receives the third portion.

Abstract: An adapter has a cradle portion that can removably receive a radio frequency identification tag. A first electrical connector is positioned in the cradle portion so that, when a tag is removably received in the cradle portion, the first electrical connector electrically couples the adapter to the tag. A second electrical connector is disposed on the adapter at a location spaced from the cradle portion, and the adapter includes structure that electrically couples the first and second electrical connectors.

Abstract: A tag can receive first and second wireless signals respectively defining first and second transmission fields that overlap. When the tag moves from the first field to the second field through the region of overlap, the apparatus transitions only once from recognizing the tag is in the first field to recognizing the tag is in the second field. According to another aspect, first and second signposts are supported at spaced locations in the region of a crane, and respectively transmit first and second wireless signals that are different, and that respectively define first and second fields of transmission. According to yet another aspect, a signpost transmits wireless signals having a transmission field, and a system senses positional information regarding a tag movable relative to the signpost, the system using the positional information to determine a location of the tag in relation to the transmission field.

Abstract: A tag has a receiver section, a transmitter section, and a further section, the further section being responsive to receipt by the receiver section of a wireless signpost signal from one signpost in a group of signposts for thereafter inhibiting transmission of tag signals by the transmitter section pending receipt by the receiver section of a respective signpost signal from each signpost in the group. A different configuration includes a tag having a receiver section, a transmitter section, and a further section, the further section inhibiting transmission of tag signals by the transmitter section during a time period that ends as a function of the absence of receipt by the receiver section of signpost signals, the further section responding to receipt of signpost signals by the receiver section during the time period by saving information relating to signposts that generated the signpost signals.

Abstract: Spaced first and second signposts transmit wireless signals containing different signpost identifications. A first path of travel passes through the transmission range of the first signpost, and a second path of travel passes through the transmission range of the second signpost but not the transmission range of the first signpost. A different configuration includes plural hallways extending away from a common intersection in respective directions, with a respective signpost in each hallway that transmits wireless signals containing a respective different signpost identification.

Abstract: A tag has circuitry with a communication portion that can transmit and receive wireless signals, including wireless transmission of data blocks that each have a predefined configuration with a plurality of data slots. The circuitry includes a further portion that, in response to receipt through the communication portion of a wireless communication containing a request identifying a set of plural data items, populates respective data slots in one data block with respective data items from the set, and then causes the communication portion to effect wireless transmission of that data block.

Abstract: A tag has circuitry that can transmit and receive wireless signals, including receipt of first and second wireless signals that are different. The circuitry responds to a predetermined event by inhibiting wireless transmissions for up to a selected time interval, while waiting for receipt of one of the first and second wireless signals. The circuitry responds to receipt during the selected time interval of one of the second wireless signals before receipt of one of the first wireless signals by continuing to inhibit wireless transmissions, and responds to expiration of the selected time interval without receipt of either of the first and second wireless signals by transmitting a selected wireless signal.

Abstract: An intrusion detection technique involves: emitting a wireless signal within a container; detecting the wireless signal near the container; and responding to detection of a change in a characteristic of the detected wireless signal by transmitting a wireless notification to a location remote from the container. A different technique involves: responding to a determination that a condition representative of unauthorized intrusion is present while the container is stationary by transmitting a wireless notification; and responding to a determination that the container is moving by ignoring whether the condition is present. Yet another technique involves: monitoring whether a door of a container is in a closed position; and emitting a wireless signal indicating whether the container door is in the closed position.

Abstract: A tag receives a wireless signpost signal that contains a signpost code, converts the signpost code into location information representative of a physical location of a signpost that transmitted the received signpost signal, and transmits a wireless tag signal that includes the location information. In a different configuration, a tag receives a wireless signpost signal that includes a signpost code, and determines whether the signpost that generated the received signpost signal is a replacement for a different signpost. If it is a replacement, the tag transmits a wireless tag signal containing an information portion that relates to the signpost replaced by the signpost that generated the received signpost signal.

Abstract: A tag can transmit a tag signal, and responds to receipt of a wireless signpost signal by determining whether the signpost that generated the signal is currently active. When the signpost is respectively determined to be active and inactive, the tag respectively includes and excludes from the tag signal an information portion that relates to the signpost that generated the received signpost signal. In another configuration, a tag has first and second antennas, receives wireless signpost signals through at least one of the antennas, and responds to receipt of a signpost signal containing antenna select information by causing a selected one of the first and second antennas to be disabled and the other of the first and second antennas to receive wireless signpost signals.

Abstract: A tag stores information identifying the sequence in which it received wireless signpost signals from different signposts. In another configuration, a tag maintains data identifying a group of signposts that are to be treated as equivalent. In yet another configuration, wireless signpost signals transmitted by each of a plurality of signposts all contain the same signpost code. In still another configuration, a signpost has an interface through which a signpost code of the signpost can be selectively set.

Abstract: A tag receives wireless signpost signals that include timing data, determines time information associated with an event as a function of the timing data, and transmits a wireless tag signal that contains the time information. In a another configuration, a signpost transmits wireless signpost signals having a selected transmission range; a reader proximate to the signpost receives wireless tag signals with a reception range that is approximately the same as the selected transmission range; and a tag movable relative to the signpost and reader responds to receipt of a wireless signpost signal by transmitting a wireless tag signal containing a tag code associated with the tag.

Abstract: A support includes a base having an outwardly extending projection with a passageway therethrough, and having a tag receiving portion configured to removably support a tag on the base adjacent one end of the passageway. A different arrangement involves a tag that includes a housing having an opening therethrough and having an annular surface around the opening, an annular gasket engaging the annular surface, and circuitry within the housing having a sensor located in the region of the opening and having a transmitter that can transmit wireless signals. A method includes defining a passageway that provides fluid communication between an interior and exterior of a container, supporting a tag on the exterior of the container, and causing the tag to sense, at a location in the region of an end of the passageway, a condition within the container.

Abstract: One aspect of the invention involves: maintaining a record of how long a circuit operates in each of a plurality of different operating modes thereof, starting from a point in time at which a battery that powers the circuit is replaced; calculating for each of the operating modes as a function of the record a cumulative current drain from the point in time to a current time; and determining as a function of the cumulative current drains whether the battery is subject to a low voltage condition. Another aspect involves: monitoring a voltage of a battery; periodically determining whether the voltage of the battery is subject to a low voltage condition; and maintaining a count of the number of times that the determining results in a determination that the battery is subject to a low voltage condition.

Abstract: One aspect of the invention involves: periodically sampling a voltage of a battery and an ambient temperature in order to obtain a sample that includes a temperature value and a voltage value; saving each sample in a sample group; selecting a subset of the samples in the group, wherein the temperature value of each sample in the subset is lower than the temperature value of substantially all of the samples of the group other than the subset; and determining as a function of the voltage of at least one the sample in the subset whether the battery is subject to a low voltage condition.

Abstract: One aspect of the invention involves: monitoring a voltage of a battery over time; evaluating whether a rate of voltage decrease of the battery is in excess of a threshold; and indicating that the battery is subject to a low voltage condition when the rate of voltage decrease exceeds the threshold. Another aspect of the invention involves: causing a circuit powered by a battery to respond to battery replacement by thereafter applying a selected load to the battery during a selected time interval. A further aspect involves: periodically sampling a voltage of a battery; and applying a load to the battery during a selected time interval before each sampling of the battery voltage.

Abstract: A tag includes a housing, an antenna disposed within the housing, and circuitry within the housing that is electrically coupled to the antenna. A battery within the housing is electrically coupled to the circuitry, the battery being positioned so as to avoid significant interference with electromagnetic fields associated with the antenna. A tag holder can be detachably coupled to a radio frequency tag, and has structure facilitating attachment of the tag holder to an object other than a tag. A tag includes a circuit and an antenna, the antenna having a plurality of conductive segments and capacitors that are coupled in series to form an endless loop.

Abstract: An adapter has a cradle portion that can removably receive a radio frequency identification tag. A first electrical connector is positioned in the cradle portion so that, when a tag is removably received in the cradle portion, the first electrical connector electrically couples the adapter to the tag. A second electrical connector is disposed on the adapter at a location spaced from the cradle portion, and the adapter includes structure that electrically couples the first and second electrical connectors.

Abstract: An apparatus (10, 240, 300) includes a signpost (11, 241-256, 322, 612, 623, 626-628, 652, 661, 682, 686, 703) which transmits signpost signals (24) that are received by a tag (12, 271-275, 301-316, 395-397, 616-618, 641-643, 653, 656-657, 662-664, 679, 708, 711). The tag in turn transmits radio frequency beacon signals (72) which are received by a reader (13, 261, 319, 521-530). The tag can vary the duration of the beacon signals, for example in dependence on whether it is currently receiving a signpost signal. Further, the tag can dynamically vary the transmission rate and/or transmission power of the beacon signals, for example following receipt of a signpost signal. Varying these parameters can facilitate compliance with governmental regulations.