Abstract: A system for electronically recording an event that provides mechanical energy to a structure includes the structure and an event sensing and recording node. The event sensing and recording node is mounted on the structure and includes a sensor and a first electronic memory. The sensor includes a device for converting the mechanical energy into an electrical signal. The first electronic memory uses energy derived from the electrical signal for electronically recording the event. All energy for sensing the event and recording the event in the first electronic memory is derived from the mechanical energy.

Abstract: A device for harvesting an external source of energy includes an electricity generating device, a flexure, and a first stop. Displacement of the flexure is limited by the first stop. The flexure has a vibration amplitude, wherein the vibration amplitude is amplitude the flexure would have if unconstrained by the first stop. The first stop allows the flexure to oscillate with a vibration amplitude that is higher than displacement of the flexure as limited by the first stop. The electricity generating device generates electrical energy while the first stop allows the flexure to oscillate with the higher vibration amplitude.

Abstract: A device includes a structure, a strain sensor and a light curable adhesive. The structure has a structure surface. The light curable adhesive bonds the strain sensor to the structure surface.

Abstract: A device for harvesting an external source of energy includes an electricity generating device, a flexure, and a restoring spring. The electricity generating device generates electricity based on movement of the flexure. The flexure has a first stable position. When disregarding presence of the restoring spring the flexure also has a second stable position different from the first stable position. The restoring spring is positioned so when the flexure snaps from the first stable position toward the second stable position the restoring spring provides a restoring spring force to restore the flexure toward the first stable position. Substantially greater force is needed to snap the flexure from the first stable position toward the second stable position to overcome the restoring spring force than is required to snap the flexure from the second stable position toward the first stable position.

Abstract: An apparatus includes a hermetically sealed housing formed of conductive material. The hermetically sealed housing contains a circuit that includes a power supply and a power using element. The power supply has a power receiving element within the hermetically sealed housing for receiving electromagnetic radiation having a frequency low enough to penetrate through the conductive material. The power supply is connected to provide electrical energy derived from the electromagnetic radiation for powering the power using element.

Abstract: A device includes a removable load element. The removable load element includes a pin portion and a housing portion. The pin portion extends from the housing portion. The pin portion includes a sensor. The housing portion includes an electronic circuit connected to the sensor.

Abstract: A device for providing displacement information includes a housing holding a displacement sensor. The displacement sensor includes a coil and a captive core. An electrical measurement of the coil provides information about displacement of the core. The coil has an axis extending in a first direction, wherein the housing has a minimum outside dimension that is less than 3.00 mm when measured perpendicular to that first direction. The housing has an inner surface having a housing inside dimension. The housing is for holding a displacement sensor and a guidance mechanism. The displacement sensor includes a coil and a captive core having a core outside dimension. The guidance mechanism includes a first part and a second part for guiding the core. The first part includes a bearing connected to the housing. The bearing has an axial hole having a hole dimension about equal to the core outside dimension. The core slidably extends through this axial hole.

Abstract: One embodiment of the present patent application is a method of monitoring a rotating part. The method includes providing a shaft, a sensor, a processor, an energy storage device, and a transmitter. The method further includes mounting the sensor directly on the shaft and mounting said processor, said energy storage device, and said transmitter to rotate with said shaft. The method further includes rotating the shaft and waking the processor for a period of time and drawing energy to the processor from the energy storage device to provide the processor in an active mode during the period of time. The method also includes sampling the sensor during the period of time. It also includes returning the processor to sleep mode. The method also includes transmitting data derived from the sensor.

Abstract: A method of navigation includes providing an angular rate sensor and a direction-of-gravity reference. The method also includes determining bias error of the angular rate sensor about a vertical axis based on data substantially from the angular rate sensor and from the direction-of-gravity reference. In one embodiment, the first angular rate sensor is moved from a first position around a substantially horizontal axis to a second position around the substantially horizontal axis. The first angular rate sensor provides angular rate data for attitude at the first position and for compass heading at the second position. Data from the first angular rate sensor and from the direction-of-gravity reference is processed with a program for determining a bias error correction for the first angular rate sensor while the first angular rate sensor is in the first position.

Abstract: A data collection apparatus includes a network of sensing units for sensing a parameter. Each sensing unit of the network of sensing units includes a sensor, a first data storage device, a first receiving device, and a first transmitting device. The first data storage device is for storing data from the sensor. The first transmitting device is for transmitting data derived from the sensor. The apparatus also includes a single control unit. The single control unit includes a second receiving device, a second transmitting device, and a second data storage device. The second receiving device is for receiving data transmitted from the network of sensing units. The second data storage device is for storing the data received from the network of sensing units.

Abstract: A system includes a measuring tool, a fixture, and a rotatable target. The measuring tool includes a light source, an imaging device, and an electronic circuit. The fixture allows the rotatable target to rotate about an axis. The rotatable target includes a surface having microscopic asperities. The imaging device is mounted to provide a sequence of images derived from said microscopic asperities. The electronic circuit is connected to the imaging device for measuring rotation of the rotatable target from the sequence of images.

Abstract: An energy harvesting system includes a composite structure that has a first spring, a piezoelectric structure, and a proof mass. The piezoelectric structure and the proof mass are mounted on the first spring. The composite structure has a natural frequency of vibration. The natural frequency of vibration of the composite structure is automatically adjustable.

Abstract: An energy harvesting system includes a composite structure that includes a base spring and a first piezoelectric element. The first piezoelectric element is mounted on the base spring. The base spring has a base spring thickness, a base spring length, and a base spring width. The base spring is for vibrating around an axis parallel to the base spring width. The base spring thickness varies from position to position along a direction parallel to the base spring length. The base spring thickness varies to provide the first piezoelectric element with constant strain when the base spring vibrates around the axis parallel to the base spring width.

Abstract: A mobile system powers, charges, and communicates with separate devices, such as sensors and actuators. The mobile system includes an unmanned vehicle for approaching and wirelessly electromagnetically powering the separate device.

Abstract: In one embodiment a device comprises a composite structure that includes a piezoelectric flexure and a length-constraining element. The length-constraining element provides the piezoelectric flexure with a bowed shape. The piezoelectric flexure has a first stable bowed position and a second stable bowed position. The length-constraining element is one from the group consisting of a planar sheet and a columnar rod. In another embodiment a device comprises a piezoelectric flexure having a bowl shape. The piezoelectric flexure has a first stable bowl-shaped position and a second stable bowl-shaped position.

Abstract: An electronic system includes a reader and a remotely powered and remotely interrogated sensor transponder. The sensor transponder includes a reader and a remotely powered and remotely interrogated sensor transponder. The sensor transponder includes a sensor and a radiation receiving device. Data from the sensor is conditioned to provide sensor data ratiometric with magnitude of excitation voltage provided by the radiation receiving device.

Abstract: A network of wireless sensor nodes for wireless transmission to a base station is provided. The sensor nodes can provide real time streaming of data over separate frequency links that can all be received by the base station. The base station includes a receiver for receiving at multiple frequencies, error detection or correction, and analog outputs so sensor data can be provided to standard analysis systems that require analog signals as would be provided by wired sensors. The base station also provides an output indicating the presence of transmission error.

Abstract: A system includes a structure and a circuit. The circuit is mounted to the structure. The circuit includes a sensor, a non-volatile memory, and a voltage sensitive switch. The memory and the voltage sensitive switch are connected for recording an event sensed by said sensor. The recording only uses power derived from the sensor. One embodiment of the circuit includes a processor connected for receiving a signal derived from the sensor. In this embodiment the non-volatile memory is connected to the processor for receiving and storing data derived from the signal. In one embodiment a first energy storage device is connected to receive energy from the sensor. The voltage sensitive switch is connected for releasing energy from the first energy storage device when energy stored in the first energy storage device exceeds a threshold. The processor and the non-volatile memory are connected for receiving power from the released energy.

Abstract: A method of maintaining a structure includes providing a structure having a component subject to failure. A sensor, a memory and an energy harvesting device are mounted on the structure. The sensor is used and data derived from the sensor logged in the memory, wherein the memory is powered solely with energy derived from the energy harvesting device. The component is replaced if information in the memory shows that the component was subject to damaging usage.

Abstract: A sensing device includes a circuit that compensates for time and spatial changes in temperature. The circuit includes elements to correct for variation in permeability of a highly permeable core of a differential variable reluctance transducer as temperature changes. The circuit also provides correction for temperature gradients across coils of the transducer.