Abstract: A method of detecting at least a blockage status in a porous member separating a measurement chamber of a device including a gas sensor positioned within the measurement chamber which is responsive to an analyte in an ambient environment to be sampled, includes emitting pressure waves from a pressure wave source which travel within the measurement chamber, measuring a first response via a first sensor responsive to pressure waves positioned at a first position within the measurement chamber, measuring a second response via a second sensor at a second position, different from the first position, and in fluid connection with the pressure wave source, determining the blockage status of the porous member based upon a functional relation of the first response and the second response.

Abstract: A system includes a two-conductor loop in which the loop current or current signal is controlled by a loop current controller to be proportional to a signal output from a sensor. The system further includes energy harvesting circuity in electrical connection with the two-conductor loop which includes a second current controller in parallel electrical connection with the loop current controller and a power converter in electrical connection with the second current controller. The second current controls a portion of current drawn from the two-conductor loop and delivered to the power converter from an output port thereof. The portion of the current drawn from the two-conductor loop is returned to the loop current controller from the energy harvesting circuit. Noise in the portion of the current drawn from the two-conductor loop by the second current controller is controlled by the second current controller to be below a predetermined threshold.

Abstract: A method of detecting at least a blockage status in a porous member separating a measurement chamber of a device including a gas sensor positioned within the measurement chamber which is responsive to an analyte in an ambient environment to be sampled, includes emitting pressure waves from a pressure wave source which travel within the measurement chamber, measuring a first response via a first sensor responsive to pressure waves positioned at a first position within the measurement chamber, measuring a second response via a second sensor at a second position, different from the first position, and in fluid connection with the pressure wave source, determining the blockage status of the porous member based upon a functional relation of the first response and the second response.

Abstract: A system includes a two-conductor loop in which the loop current or current signal is controlled by a loop current controller to be proportional to a signal output from a sensor. The system further includes energy harvesting circuity in electrical connection with the two-conductor loop which includes a second current controller in parallel electrical connection with the loop current controller and a power converter in electrical connection with the second current controller. The second current controls a portion of current drawn from the two-conductor loop and delivered to the power converter from an output port thereof. The portion of the current drawn from the two-conductor loop is returned to the loop current controller from the energy harvesting circuit. Noise in the portion of the current drawn from the two-conductor loop by the second current controller is controlled by the second current controller to be below a predetermined threshold.

Abstract: A system includes a two-conductor loop in which the loop current or current signal is controlled by a loop current controller to be proportional to a signal output from a sensor. The system further includes energy harvesting circuitry in electrical connection with the two-conductor loop which includes a second current controller in parallel electrical connection with the loop current controller and a power converter in electrical connection with the second current controller. The second current controls a portion of current drawn from the two-conductor loop and delivered to the power converter from an output port thereof. The portion of the current drawn from the two-conductor loop is returned to the loop current controller from the energy harvesting circuit. Noise in the portion of the current drawn from the two-conductor loop by the second current controller is controlled by the second current controller to be below a predetermined threshold.

Abstract: A gas sensor device including a housing, a porous member through which the analyte gas is transportable in operative connection with the a of the housing to separate an inner chamber of the housing from the ambient environment, a gas sensor responsive to the analyte gas within the inner chamber, a source of pressure waves positioned within the inner chamber and spaced from the porous member so that any pressure waves emitted from the source of pressure waves that are transmitted out of the inner chamber are transmitted through the porous member, a sensor responsive to pressure waves, and circuitry in operative connection with the sensor responsive to pressure waves to relate a phase of a measured response of the sensor responsive to pressure waves to a state of blockage in the porous member.

Abstract: A gas sensor device to detect an analyte gas in an ambient environment includes a housing including an inner chamber and a port, a porous member through which the analyte gas transports in operative connection with the port to separate the inner chamber from the ambient environment, a sensor responsive to the analyte positioned within the inner chamber, a source of pressure waves positioned within the inner chamber, a sensor responsive to pressure waves positioned within the inner chamber; and circuitry in operative connection with the sensor responsive to pressure waves to relate a response of the sensor responsive to pressure waves to a state of blockage in the porous member.

Abstract: A method of detecting at least a blockage status in a porous member separating a measurement chamber of a device including a gas sensor positioned within the measurement chamber which is responsive to an analyte in an ambient environment to be sampled, includes emitting pressure waves from a pressure wave source which travel within the measurement chamber, measuring a first response via a first sensor responsive to pressure waves positioned at a first position within the measurement chamber, measuring a second response via a second sensor at a second position, different from the first position, and in fluid connection with the pressure wave source, determining the blockage status of the porous member based upon a functional relation of the first response and the second response.

Abstract: A method of detecting at least a partial blockage in a porous member separating an inner chamber of a device having a gas sensor responsive to an analyte positioned within the inner chamber and an ambient environment includes emitting pressure waves within the inner chamber and measuring a response via a sensor responsive to pressure waves positioned within the inner chamber.

Abstract: A method of detecting at least a partial blockage in a porous member separating an inner chamber of a device having a gas sensor responsive to an analyte positioned within the inner chamber and an ambient environment includes emitting pressure waves within the inner chamber and measuring a change in phase of a response via a sensor responsive to pressure waves.

Abstract: A system includes a two-conductor loop in which the loop current or current signal is controlled by a loop current controller to be proportional to a signal output from a sensor. The system further includes energy harvesting circuitry in electrical connection with the two-conductor loop which includes a second current controller in parallel electrical connection with the loop current controller and a power converter in electrical connection with the second current controller. The second current controls a portion of current drawn from the two-conductor loop and delivered to the power converter from an output port thereof. The portion of the current drawn from the two-conductor loop is returned to the loop current controller from the energy harvesting circuit. Noise in the portion of the current drawn from the two-conductor loop by the second current controller is controlled by the second current controller to be below a predetermined threshold.

Abstract: A method of detecting at least a partial blockage in a porous member separating an inner chamber of a device having a gas sensor responsive to an analyte positioned within the inner chamber and an ambient environment includes emitting pressure waves within the inner chamber and measuring a change in phase of a response via a sensor responsive to pressure waves.

Abstract: A method of detecting at least a partial blockage in a porous member separating an inner chamber of a device having a gas sensor responsive to an analyte positioned within the inner chamber and an ambient environment includes emitting pressure waves within the inner chamber and measuring a response via a sensor responsive to pressure waves positioned within the inner chamber.