Abstract: A two-wire reference accelerometer includes integrated mechanical transducing and self-calibration capability based on gravity only. The reference accelerometer includes an external two-wire connector and an internal three-wire transducer that responds to both steady-state acceleration and time-varying accelerations by producing a modulated transducer output signal having a steady-state waveform when the transducer senses steady state acceleration and a time-varying waveform when the transducer senses time-varying accelerations. A signal conditioning circuit conditions the transducer output signal and applies it to the two-wire electrical connector as a modulated reference accelerometer output signal. The transducer and the signal conditioning circuit can operate without modification in either a DUT calibration mode or a self-calibration mode.

Abstract: A piezoelectric pressure sensor is characterized by a piezoelectric transducer having substantially parallel piezoelectric plate faces oriented in planes that extend substantially parallel a principal longitudinal axis of the sensor, a pair of clamping members engaging the piezoelectric plate faces, a membrane cap covering the clamping members and mounted on a stem to define an enclosed protective chamber that isolates the piezoelectric transducer and the clamping members from an environment outside the membrane cap. The membrane cap has a membrane wall engaging outside faces of the clamping members. The membrane wall undergoes inward deflections in response to pressure increases in the environment outside the membrane cap. The clamping members undergo corresponding inward deflections in response to the inward deflections of the membrane wall.

Abstract: A piezoelectric pressure sensor is characterized by a piezoelectric transducer having substantially parallel piezoelectric plate faces oriented in planes that extend substantially parallel a principal longitudinal axis of the sensor, a pair of clamping members engaging the piezoelectric plate faces, a membrane cap covering the clamping members and mounted on a stem to define an enclosed protective chamber that isolates the piezoelectric transducer and the clamping members from an environment outside the membrane cap. The membrane cap has a membrane wall engaging outside faces of the clamping members. The membrane wall undergoes inward deflections in response to pressure increases in the environment outside the membrane cap. The clamping members undergo corresponding inward deflections in response to the inward deflections of the membrane wall.

Abstract: A universal sensor mount for mounting a sensor module to a machine in a precise orientation and a corresponding sensor module installation method. The universal sensor mount includes a main body having a central main axis. A machine mounting member extends from the main body in a first direction substantially parallel to the main axis for attachment to the machine. A threaded sensor module mounting member extends from the main body in a second direction substantially parallel to the main axis for threaded attachment to the sensor module. The sensor module mounting member is rotatable relative to the main body. An adjustable locking member in the main body is operable to lock the sensor module mounting member in a selected rotational position. The selected rotational position of the sensor module mounting member determines a rotational position of the sensor module when it is attached to the sensor module mounting member.

Abstract: A universal sensor mount for mounting a sensor module to a machine in a precise orientation and a corresponding sensor module installation method. The universal sensor mount includes a main body having a central main axis. A machine mounting member extends from the main body in a first direction substantially parallel to the main axis for attachment to the machine. A threaded sensor module mounting member extends from the main body in a second direction substantially parallel to the main axis for threaded attachment to the sensor module. The sensor module mounting member is rotatable relative to the main body. An adjustable locking member in the main body is operable to lock the sensor module mounting member in a selected rotational position. The selected rotational position of the sensor module mounting member determines a rotational position of the sensor module when it is attached to the sensor module mounting member.

Abstract: A sensor with integrated mechanical transducing and temperature monitoring capability is provided. The sensor includes housing containing a transducer, a temperature sensor with associated bias, a summing circuit, and a two-wire cable connector. The transducer is operable to output a dynamic transducer waveform that corresponds to dynamic mechanical perturbations sensed by the transducer. The temperature sensor is operable to output a quasi-static temperature waveform that corresponds to temperatures sensed by the temperature sensor. The summing circuit is operable to combine the transducer waveform and the temperature waveform into a composite modulated voltage bias output signal or a modulated current bias output signal. The two-wire cable connector is accessible on an outside of the housing and is connectable to a two wire cable that delivers power to the sensor from a power source and delivers the composite output signal from the sensor to a remote data acquisition circuit.

Abstract: A vibration sensor includes a piezoelectric crystal; and a base having an upper surface and a lower surface, the piezoelectric crystal attached to the upper surface of the base, the base defining a notch in at least one of the upper surface and the lower surface. Another embodiment of a vibration sensor includes a first piezoelectric crystal; a second piezoelectric crystal; a base attached to the first piezoelectric crystal on first side of the base and attached to the second piezoelectric crystal on a second side of the base opposite the first side of the base; a voltage amplifier in electrical communication to the first piezoelectric crystal; and a charge amplifier in electrical communication to the second piezoelectric crystal.

Abstract: A sensor with integrated mechanical transducing and temperature monitoring capability is provided. The sensor includes housing containing a transducer, a temperature sensor with associated bias, a summing circuit, and a two-wire cable connector. The transducer is operable to output a dynamic transducer waveform that corresponds to dynamic mechanical perturbations sensed by the transducer. The temperature sensor is operable to output a quasi-static temperature waveform that corresponds to temperatures sensed by the temperature sensor. The summing circuit is operable to combine the transducer waveform and the temperature waveform into a composite modulated voltage bias output signal or a modulated current bias output signal. The two-wire cable connector is accessible on an outside of the housing and is connectable to a two wire cable that delivers power to the sensor from a power source and delivers the composite output signal from the sensor to a remote data acquisition circuit.

Abstract: A vibration sensor includes at least one piezoelectric crystal having an upper surface and a lower surface; a base having an attachment section defining an attachment surface and an at least one calibration mass; wherein a one of the at least one piezoelectric crystal upper surface and lower surface attaches to the attachment surface of the base; and wherein the at least one calibration mass is external to the piezoelectric crystal.

Abstract: A hand-held or portable vibration sensor device having a housing and a sensor body which generally provides a single point of contact with the machinery or apparatus for which vibration measurement is desired. In one aspect, the sensor body comprises a vibration sensor element such as an accelerometer for measuring vibration. In another aspect, a force sensor such as a force sensing resistor or load cell is provided to reduce the impact of forces applied to said hand-held vibration sensor such as a force applied through a handle during measurement. In another aspect, a compensation circuit processes the out put from a vibration sensor element to provide a relatively flat frequency response over a desired operational frequency range. The hand-held vibration sensor may also comprise a rubber isolation member disposed between the sensor body and force sensor.

Abstract: An electrical connector includes a machined metal contact housing having a contact housing cavity surrounded by a contact housing wall. Two or more electrical contacts are disposed within the contact housing cavity. A polarization alignment key is disposed on an inside surface of the contact housing wall. A key-retaining pocket on the contact housing intersects an inside surface of the contact housing wall to form a longitudinal slot opening between the key-retaining pocket and the contact housing cavity. The key is mounted on the contact housing by virtue of a portion thereof being disposed in the key-retaining pocket. The electrical connector may be manufactured by (1) machining the key-retaining pocket in a metal blank from which the contact housing will be formed, (2) machining the contact housing cavity in the blank so as to intersect the key-retaining pocket, (3) mounting the key, and (4) mounting the electrical contacts.

Abstract: A vibration sensor includes a piezoelectric crystal; and a base having an upper surface and a lower surface, the piezoelectric crystal attached to the upper surface of the base, the base defining a notch in at least one of the upper surface and the lower surface. Another embodiment of a vibration sensor includes a first piezoelectric crystal; a second piezoelectric crystal; a base attached to the first piezoelectric crystal on first side of the base and attached to the second piezoelectric crystal on a second side of the base opposite the first side of the base; a voltage amplifier in electrical communication to the first piezoelectric crystal; and a charge amplifier in electrical communication to the second piezoelectric crystal.

Abstract: A vibration sensor includes at least one piezoelectric crystal having an upper surface and a lower surface; a base having an attachment section defining an attachment surface and an at least one calibration mass; wherein a one of the at least one piezoelectric crystal upper surface and lower surface attaches to the attachment surface of the base; and wherein the at least one calibration mass is external to the piezoelectric crystal.

Abstract: A signal-transmitting arrow operable to transmit an encoded RF signal, an arrow locating and game tracking receiver system for use with the signal-transmitting arrow, and a transmitter-nock unit for installation on an arrow to construct a signal-transmitting arrow. The arrow includes an arrow shaft, an arrow head disposed at an arrow shaft forward end, and a nock disposed at an arrow shaft rearward end. A transmitter unit includes a transmitter housing that is removably mounted in interior chamber at the rearward end of the arrow shaft, and is rigidly connected to the nock to provide the transmitter-nock unit. The transmitter unit has an RF transmitter with a rigid antenna that extends rearwardly into the nock. The receiver system includes omnidirectional and directional antennas and RF receivers, a processor for generating direction indicating signal, and a user interface that indicates arrow location.

Abstract: A mechanical vibration switch having a magnet connected to a bar that rotates about an axis, an inertial mass connected to the bar, a magnetic material part disposed in a predetermined spaced apart relation from the magnet, a spring, a stop, and an electrical relay mechanically actuated by the bar. The magnetic material part is adjusted parallel to the magnet such that the magnetic force varies approximately linearly with the common surface area S between the face of the magnet and the face of the magnetic material part.

Abstract: A hand-held or portable vibration sensor device having a housing and a sensor body which generally provides a single point of contact with the machinery or apparatus for which vibration measurement is desired. In one aspect, the sensor body comprises a vibration sensor element such as an accelerometer for measuring vibration. In another aspect, a force sensor such as a force sensing resistor or load cell is provided to reduce the impact of forces applied to said hand-held vibration sensor such as a force applied through a handle during measurement. In another aspect, a compensation circuit processes the out put from a vibration sensor element to provide a relatively flat frequency response over a desired operational frequency range. The hand-held vibration sensor may also comprise a rubber isolation member disposed between the sensor body and force sensor.

Abstract: A mechanical vibration switch having a magnet connected to a bar that rotates about an axis, an inertial mass connected to the bar, a magnetic material part disposed in a predetermined spaced apart relation from the magnet, a spring, a stop, and an electrical relay mechanically actuated by the bar. The magnetic material part is adjusted parallel to the magnet such that the magnetic force varies approximately linearly with the common surface area S between the face of the magnet and the face of the magnetic material part.

Abstract: A signal-transmitting arrow operable to transmit an encoded RF signal, an arrow locating and game tracking receiver system for use with the signal-transmitting arrow, and a transmitter-nock unit for installation on an arrow to construct a signal-transmitting arrow. The arrow includes an arrow shaft, an arrow head disposed at an arrow shaft forward end, and a nock disposed at an arrow shaft rearward end. A transmitter unit includes a transmitter housing that is removably mounted in interior chamber at the rearward end of the arrow shaft, and is rigidly connected to the nock to provide the transmitter-nock unit. The transmitter unit has an RF transmitter with a rigid antenna that extends rearwardly into the nock. The receiver system includes omnidirectional and directional antennas and RF receivers, a processor for generating direction indicating signal, and a user interface that indicates arrow location.