Abstract: A gravity-enforced photon momentum radiometer incudes: a magnetic array; a diamagnetic shuttle that levitates above the magnetic array; a mirror on the diamagnetic shuttle that receives laser light and moves the diamagnetic shuttle due to the optical force; a tiltable platform for the magnetic array; a photogate producing gate light that can be blocked by a photo interrupter and that produces a detector signal that provides a position of the diamagnetic shuttle relative to the tiltable platform for determining a position of the diamagnetic shuttle relative to the photogate.

Abstract: Proposed is an elastic body having variable rigidity, wherein the elastic body is used in a series elastic actuator module, connects an input and an output, and has a rigidity that varies according to the applied torque. The elastic body having variable rigidity comprises: a connection part which receives torque from the input side or the output side; and a spring part connected to and receiving torque from the one selected from among the input side and the output side which is different from the connection part, wherein the spring part is formed integrally with the connection part and has a rigidity that varies as the connection part and the spring part come into contact with each other due to deformation caused by the applied torque.

Abstract: Methods, devices, and systems for airfield luminaire vibration monitoring are described herein. In some examples, one or more embodiments include a computing device comprising a memory and a processor to execute instructions stored in the memory to receive a vibration signal from a sensor on an airfield luminaire, compare the vibration signal from the sensor to a vibration profile for the airfield luminaire, and determine a status of a bolt of the airfield luminaire based on the comparison.

Abstract: A communication device includes an interface connector for connecting to a computing device to receive a media data and an external power supply, a transmission subsystem for transmitting the media content to a network, a battery power supply, a controller circuit powered by the battery power supply, a sensor, communicatively coupled to the controller circuit, for detecting a movement of the communication device, and a switch circuit for switchably connecting the battery power supply to the transmission subsystem responsive to a first switch control signal that is generated based on a motion detection signal generated by the controller circuit responsive to a detection of the movement by the sensor.

Abstract: A MEMS vibration sensor die can include a substrate having a top portion, a mounting surface, and an aperture extending at least partially through the substrate. The die can include a first electrode coupled to the top portion of the substrate and positioned over the aperture. The die can include a second electrode disposed between the substrate and the first electrode. The second electrode can be spaced apart from the first electrode. The die can include a proof mass that can have a first portion coupled to the first electrode or the second electrode. The proof mass can have a second end opposite the first portion. The second end can be recessed within the aperture relative to the mounting surface of the substrate. The proof mass can be suspended freely within the aperture. The proof mass can move the first electrode or the second electrode from which it is suspended in response to vibration.

Abstract: A method of making an acoustic wave sensor includes the steps of providing a piezoelectric substrate layer and printing on the substrate layer a sensor layer comprising a first interdigitated acoustic wave transducer, a sensing film, and positioned on an opposing side of the sensing film from the first interdigitated acoustic wave transducer at least one selected from the group consisting of a second interdigitated acoustic wave transducer and a Bragg reflector. An insulation layer can be printed. An antenna can be printed in an antenna layer, and the insulation layer can be interposed between the antenna layer and the sensor layer. An electrical connection can be printed between the antenna and the first interdigitated acoustic wave transducer. An acoustic wave sensor is also disclosed.

Abstract: A three-dimensional sensor system made from an assembly of three either semi- or fully independently oriented sensors, each of which has a working principle based on detecting the movement of a floating magnet supported by magnetic levitation. The sensor system can be used for fall detecting, tilting monitoring and vibration tracking. The volume fabrication method of making individual sensor for such as system is also given.

Abstract: A folded pendulum is described. The folded pendulum can be a monolithic pendulum and is positioned in the vertical configuration. The folded pendulum allows for more compact realizations through high decouplings of a vertical degree of freedom from other degrees of freedom as well as optimal mechanical quality factors.

Abstract: The embodiments relate to the use of one or more phase lock loops (PLL's) for detecting wobble of a surface upon which a computing device is set. The PLL's can be configured to lock onto an exponentially-damped sinusoid output from an accelerometer in order to differentiate between surface-induced movement and direct human-induced movement of the computing device. Reduced latency in wobble detection can be achieved by implementing the PLL in software and using multiple PLL's per accelerometer axis. Further reduction in the latency of wobble detection can be achieved by seeding the phase of an oscillator signal generated by each PLL in order to improve phase estimates when attempting to lock a PLL onto the accelerometer output.

Abstract: A pseudo rock includes a housing, a strain sensor, a three-axis acceleration sensor, a vibration generator and a controller. The housing has an average shape and size of rocks. The strain sensor detects a stress acting in positive and negative directions of each axis with respect to three-dimensional coordinates using the center of the housing as the origin. The three-axis acceleration sensor detects acceleration acting in each axis of the three-dimensional coordinates. The vibration generator produces vibration in a specific direction with respect to the three-dimensional coordinates. The controller converts respective detected values of the strain sensor and the three-axis acceleration sensor into vibration pulses of specific patterns and outputting the vibration pulses to the vibration generator.

Abstract: The invention concerns a folded pendulum, comprising: a support (F); a test mass (PM); a simple pendulum (SP); an inverted pendulum (IP); the simple pendulum and the inverted pendulum being connected at one of their ends to the test mass (PM) and at the other end to the support (F) by means of 4 corresponding joint systems (G), the test mass being not connected to the support (F) and being therefore free to oscillate, each joint system (G) relevant to the simple pendulum (PS) comprising one or more joints in tension, the folded pendulum being characterized in that: each of the joint systems (G) relevant to the inverted pendulum (IP) comprises one or more joints in compression. The invention further concern a seismic sensor utilizing the folded pendulum according to the invention.

Abstract: A MEMS rate sensor device. In an embodiment, the sensor device includes a MEMS rate sensor configured overlying a CMOS substrate. The MEMS rate sensor can include a driver set, with four driver elements, and a sensor set, with six sensing elements, configured for 3-axis rotational sensing. This sensor architecture allows low damping in driving masses and high damping in sensing masses, which is ideal for a MEMS rate sensor design. Low driver damping is beneficial to MEMS rate power consumption and performance, with low driving electrical potential to achieve high oscillation amplitude.

Abstract: A vibration sensor (5) mountable to a wind turbine generator for detecting excessive vibration of the wind turbine generator, the sensor comprising a pendulum having a pendulum bob (25) of pre-determined mass coupled to a detection switch (10), the detection switch arranged to detect oscillation of the pendulum exceeding a predetermined oscillation threshold; said pendulum bob selectively adjustable along said pendulum so as to vary the oscillation threshold of said sensor; wherein the sensor is arranged to exceed the oscillation threshold on receiving a forced vibration corresponding to a vibration threshold of the wind turbine generator.

Abstract: A vibration-powered impact recording device that harvests power from vibrations that affect the device is provided. The recording device is affixed to an object and includes a vibration limit detection and recordation system. The system can include a suitable part that is fixed to the object, and a mass (or other suitable part) that is less firmly attached, with the relative motion between the two parts producing an electrical voltage. The electrical voltage can be used to power an information storage unit that records the details of the impact and optionally other sensors which record other parameters such as temperature, humidity etc. at the time of impact.

Abstract: Aspects of the present disclosure relate generally to indoor localization, for example, where GPS or other localization signals are unavailable. More specifically, aspects relate to using inertial navigation systems (132) such as accelerometers (136) and gyroscopes (134) to aid in the determination of the location of a user. Certain devices such as MEMS gyroscopes found in handheld client devices (104) should be calibrated to ensure accurate location information is obtained. In one aspect, a Vibration Energy Model process (FIG. 4B) is performed on shaking energy generated as a user walks with a mobile device to detect the direction the user is walking in. This information may be used as part of a signal fusion system to perform accurate indoor localization of the user, such as to provide enhanced maps and location services to the user.

Abstract: An absolute displacement sensor 1 includes a sensor housing 2 serving as a detection object; a mass body 3 having a mass m which is movably supported by the sensor housing 2 with a spring coefficient k and a damping coefficient c; a detecting means 4 which electrically detects a relative velocity of the sensor housing 2 with respect to the mass body 3; a feedback control means 5 which controls the absolute displacement of the mass body 3 attributable to the absolute displacement of the sensor housing 2 by positively feeding back the relative displacement and by negatively feeding back a relative acceleration obtained by primarily differentiating the relative velocity, respectively; and a phase lag compensation means 6 which performs phase lag compensation with respect to the relative displacement.

Abstract: A sensor for sensing bioacoustic energy includes a housing comprising an interfacing portion configured to establish coupling with a body part during use. The sensor includes a transducer element coupled to the interfacing portion of the housing and configured to sense sounds produced by matter of biological origin. One or more conductors are coupled to the transducer element. A mass element is compliantly coupled to a surface of the transducer element. Intervening material is disposed between the transducer element surface and the mass element, and allows for differential motion between the transducer element surface and the mass element during excitation of the transducer element.

Abstract: Methods, structures, devices and systems are disclosed for implementing optical seismometers that detect seismic information based on optical interferometry. In one aspect, a device includes a first retroreflector attached to a mass of a seismometer, a second retroreflector attached to a member of a frame of the seismometer, the frame structured to suspend the mass, and optical components attached to the member of the frame and configured with the first and second retroreflectors to form an interferometer, in which a change in position of the mass is identified by detecting by a change in an optical path of a light beam generated by a light energy source transmitted to the interferometer.

Abstract: Two layers of a plurality of rod-like permanent magnets each having a width Wm, a thickness Tm and a predetermined length are aligned on a plane in such a way that they have opposite magnetic pole orientations alternately and are aligned at a fixed pole pitch ?p are arranged to be opposed to each other with the magnetic pole orientation of each magnet in one of the layers being identical to that of the opposing magnet in the other layer. The opposing surfaces of the magnets are spaced a distance 2×lg from each other, and a vibrating membrane on which coils each having a conductive pattern are arranged is placed in a gap between any two adjacent rod-like permanent magnets in each of the two layers, where lg is a distance from the vibrating membrane to the surface of a magnet. The arrangement of the rod-like permanent magnets is optimized by using Wm, Tm, ?p, and lg.

Abstract: The effects of IMU gyro and accelerometer bias errors are significantly reduced in accordance with the present teachings by a system or method for commanding an IMU or vehicle through a series of preprogrammed maneuvers. The maneuvers can be designed to minimize the effects of other gyro errors including scale factor errors, nonlinearities, cross coupling/misalignment, and scale factor asymmetries. A sample maneuver is provided which demonstrates performance based on a sequence of roll and yaw maneuvers resulting in zero build up of error at the end of a maneuver cycle period as a result of these errors. Modification of the system involves the addition of control logic to determine the maneuver period, maneuver rate, and vehicle orientation. No additional hardware beyond possible fuel required to perform the maneuver is required.

Abstract: A tilt and vibration sensor incorporating a plurality of electrodes and a conductive spherical. body which is turned on and off by the moving displacement of the spherical body, and which may be remarkably reduced in size and may have high performance and high operating sensitivity, high durability, and high reliability; and a method of manufacturing the sensor. The case (1) of the sensor comprises a case body (5) formed of a non-conductive material having such excellent gas-barrier property and heat resistance that can stop the transmission of gases which affects the on/off operation of the sensor due to the moving displacement of the conductive spherical body (4) and a cover body (7) sealing airtight the opening part (6) of the case body.

Abstract: A sensor for sensing bioacoustic energy includes a housing comprising an interfacing portion configured to establish coupling with a body part during use. The sensor includes a transducer element coupled to the interfacing portion of the housing and configured to sense sounds produced by matter of biological origin. One or more conductors are coupled to the transducer element. A mass element is compliantly coupled to a surface of the transducer element. Intervening material is disposed between the transducer element surface and the mass element, and allows for differential motion between the transducer element surface and the mass element during excitation of the transducer element.

Abstract: A vibration sensor comprises a reference mass, a resilient element supporting the reference mass, and a base supporting the resilient element, and further comprises a displacement sensor for determining the distance between the reference mass and the base. In accordance with the invention the vibration sensor comprises an actuator that is situated between the resilient element and the base, a second displacement sensor, and a controller for providing an output signal to the actuator.

Abstract: A vibration-powered impact recording device that harvests power from vibrations that affect the device is provided. The recording device is affixed to an object and includes a vibration limit detection and recordation system. The system can include a suitable part that is fixed to the object, and a mass (or other suitable part) that is less firmly attached, with the relative motion between the two parts producing an electrical voltage. The electrical voltage can be used to power an information storage unit that records the details of the impact and optionally other sensors which record other parameters such as temperature, humidity etc. at the time of impact.

Abstract: Provided are a tilted vibration sensor incorporating a plurality of electrodes and a conductive spherical body which is turned on and off by the moving displacement of the spherical body, and which may be remarkably reduced in size and may have high performance and high operating sensitivity, high durability, and high reliability; and a method of manufacturing the sensor. The case (1) of the sensor comprises a case body (5) formed of a non-conductive material having such excellent gas-barrier property and heat resistance that can stop the transmission of gases which affects on the on/off operation of the sensor due to the moving displacement of the conductive spherical body (4) and a cover body (7) sealing airtight the opening part (6) of the case body. In the method of manufacturing the vibration sensor, moisture and particulate impurities affecting the on/off operation are removed from the hollow part (2) of the case (1), and the hollow part is evacuated.

Abstract: A vibration sensor for detecting a vibration of a vibrating object includes a plurality of detecting members. Each of the detecting members includes a vibrating portion disposed to be separated from the vibrating object, a transmitting portion for transmitting the vibration from the vibrating object to the vibrating portion, and a detecting portion disposed on a vibrating face of the vibration portion. The detecting portion outputs an electrical signal corresponding to a resonance of the vibrating portion. At least two of the vibrating portions of the detecting members have resonance frequencies, which are different from each other.

Abstract: An electro-magnetic driver transducer free of torque in the presence of an external magnetic field, of any direction and orientation (such as in a Magnetic Resonance Imaging environment). The transducer includes a housing. At least one coil is associated with the housing. A plurality of magnets within the housing are aligned along an axis in an anti-parallel orientation. The magnets are free to move along an axis, wherein vibration of the magnets causes vibration of the housing. The transducer may be, for example, fixed to an ossicle.

Abstract: A device having at least one screw plug for screwing into a first tapped hole of a housing or housing part of the device, the at least one screw plug including a device for sealing, such as a sealing ring, for the connection to the housing in a manner forming a seal, e.g., against the escape of oil. Introduced into the screw plug is a second tapped hole by which a sensor is releasably connectable, e.g., is able to be screwed in. The screw plug includes an end stop for conducting acoustical waves and for the simultaneous mechanical limit for screwing in the screw plug.

Abstract: A system for monitoring an exposure of a machine operator to machine vibration is provided. The system includes an operator safety restraint. The system also includes at least one vibration sensor on the safety restraint and configured to generate a signal indicative of operator exposure to machine vibration. The system further includes a controller configured to receive the signal and configured to determine an amount of vibration exposure of the machine operator based on the signal.

Abstract: An inertial shock bandpass filter for detecting a shock event between first and second acceleration levels. The inertial shock bandpass filter includes a primary inertial element and at least one secondary inertial element supported by respective spring arrangements. The inertial elements include complementary engageable gripping surfaces, which engage in response to an acceleration above the second acceleration level to prevent movement of the primary inertial element and prevent latch engagement. The primary inertial element will, in response to an acceleration between the first and second acceleration levels, engage the latch. An acceleration level below the first acceleration level is insufficient to cause either an engagement of the gripping surfaces or a latching of the primary inertial element.

Abstract: There is provided a condition detection apparatus for detecting a present operating condition of a linear rolling motion guide apparatus, and the condition detection apparatus includes an AE sensor 1 for detecting a waveform elastically generated at least due to rolling of balls included in the linear rolling motion guide apparatus and mutual collision of the balls and generating an electric detection signal corresponding the detected waveform, a waveform shaping unit 2, an A/D converter 3, and a signal processing unit 4 judging a content of the operation condition in response to the generated detected signal Sae.

Abstract: An apparatus and method effectively isolate vibrations in a lithography machine. The apparatus and method include a first control for actively reducing the vibrations in a first frequency range and a second control for actively reducing the vibrations in a second frequency range. The first control further includes a first actuator such as a force actuator and a static reference object with which relatively low-frequency vibrations are reduced. The second control further includes a second actuator such as a Piezo actuator and an air spring in which relatively high-frequency vibrations are reduced. The apparatus and method are applied to substantially prevent the vibrations on the floor from traveling to the mask stage in one embodiment.

Abstract: A washing machine includes a rotary drum for accommodating therein laundry, the rotary drum having a horizontal or slanted rotational axis; a water tub supported in a vibratable manner in a washing machine main body, the rotary drum being installed in the water tub in a rotatable manner; a motor for driving the rotary drum; an input setting unit for setting an operation of the washing machine; a control unit for controlling the motor and the operation of the washing machine set by the input setting unit, the control unit including a microcomputer; and a displacement detection unit for detecting a displacement of the water tub. The displacement detection unit includes an excitation coil, at least two detection coils having an axis coaxially aligned with the excitation coil and a core which can move along the axis.

Abstract: A sensor for use in an interactive electronic device. The sensor is operative to generate a plurality of different output signals corresponding to respective positions of the sensor relative to a reference plane. The movement of the sensor relative to the reference plane facilitates the movement of one or more actuation balls of respective switches of the sensor, which in turn results in the generation of differing conditions or output signals corresponding to closed or open circuit conditions selectively created by the switches.

Abstract: A vibration sensor capable of preventing a diaphragm electrode from being damaged without lowering sensitivity as well as realizing a satisfactory assembling process. The vibration sensor includes a fixed electrode 1, and a diaphragm electrode 3 having a weight member 2 attached to a membrane surface facing away from the fixed electrode 1 and fixedly supported at peripheries thereof, the vibration sensor being capable of outputting variation of capacitance between the fixed electrode and the diaphragm electrode as vibration signals. The vibration sensor further includes projecting portions 2a formed on parts of an end portion of the weight member 2 to project along the direction of the membrane surface and spaced from the membrane surface of the diaphragm electrode 3, and a restricting member 4 for contacting the projecting portions 2a of the weight member 2 displaced along the direction of the membrane surface of the diaphragm electrode 3, thereby to restrict displacement of the weight member 2.

Abstract: Acoustic sensing utilizing a bridge structure coupled about a portion of at least two sides of said bridge to a base substrate, wherein said bridge includes a piezoelectric section and has at least one active acoustic region proximate said bridge. A sensing material is disposed on at least a portion of at least one surface of the bridge, wherein the bridge produces stress effects measurable by an acoustic wave device located in the active acoustic region. According to one embodiment, the stress effects are measured by an acoustic wave device to sense a target matter. As target molecules accumulate on a sensing film affixed to at least a portion of the bridge, stress is produced in the bridge inducing a frequency change measured by an acoustic wave device.

Abstract: A single crystal unimorph based accelerometer has a housing base portion with a base portion bottom surface that includes two separate metallization areas. One of the two separate metallization areas is electrical active. The other is a ground electrical connection. A housing top portion is coupled to the housing base portion. A piezoelectric single crystal is positioned between the housing base portion and the housing top portion. The piezoelectric single crystal has a metal shim that forms a unimorph bonded with a metal loaded electrical conductive epoxy, and forms an electrical connection at a top electroding surface of the piezoelectric single crystal. The piezoelectric single crystal includes a cantilevered free portion that extends to the housing base portion At least a portion of the top electroding surface of the piezoelectric single crystal provides for tuning of capacitance and is an active electrical connection for the unimorph.

Abstract: A sensor for use in an interactive electronic device. The sensor is operative to generate a plurality of different output signals corresponding to respective positions of the sensor relative to a reference plane. The movement of the sensor relative to the reference plane facilitates the movement of one or more actuation balls of respective switches of the sensor, which in turn results in the generation of differing conditions or output signals corresponding to the particular pattern of electrical or conductive connection between a pad and terminals of the sensor facilitated by the switches thereof.

Abstract: An electromagnetic driver transducer free of torque in the presence of an external magnetic field, of any direction and orientation (such as in a Magnetic Resonance Imaging environment). The transducer includes a housing. At least one coil is associated with the housing. A plurality of magnets within the housing are aligned along an axis in an anti-parallel orientation. The magnets are free to move along an axis, wherein vibration of the magnets causes vibration of the housing. The transducer may be, for example, fixed to an ossicle.

Abstract: A magnetic infrasound sensor is produced by constraining a permanent magnet inside a magnetic potential well above the surface of superconducting material. The magnetic infrasound sensor measures the position or movement of the permanent magnet within the magnetic potential well, and interprets the measurements. Infrasound sources can be located and characterized by combining the measurements from one or more infrasound sensors. The magnetic infrasound sensor can be tuned to match infrasound source types, resulting in better signal-to-noise ratio. The present invention can operate in frequency modulation mode to improve sensitivity and signal-to-noise ratio. In an alternate construction, the superconductor can be levitated over a magnet or magnets. The system can also be driven, so that time resolved perturbations are sensed, resulting in a frequency modulation version with improved sensitivity and signal-to-noise ratio.

Abstract: An electronic device includes a motion sensitive power switching integrated circuit, which, in turn, includes a power switch connected between an input and an output, and a MEMS inertial sensing switch movable from a first position to a second position based upon motion thereof. The motion sensitive power switching integrated circuit also includes a detector operating the power switch to supply power to the output from the input based upon the MEMS inertial sensing switch moving from the first position to the second position. The first and second positions may be, respectively, a normally open position and a closed position. The device may be unpowered until the MEMS inertial sensing switch moves from the open to the closed position. The detector may generate a power on reset (POR) signal based upon the MEMS inertial sensing switch moving from the open to the closed position.

Abstract: A sensor for use in an interactive electronic device. The sensor comprises a housing having a side wall defining an inner surface, a top plate attached to the side wall and defining an inner surface, and a bottom plate attached to the side wall and also defining an inner surface. The inner surfaces of the side wall and the top and bottom plates collectively define an interior chamber. Disposed on the inner surface of the top plate is at least one top conductive pad, while disposed on the inner surface of the bottom plate is at least one bottom conductor pad. At least one switch partially extends into the interior chamber of the housing. Disposed within the interior chamber and rotatably connected to the housing is a trigger mechanism. The sensor is operative to generate a plurality of different conditions or states corresponding to respective positions of the housing relative to a reference plane.

Abstract: Disclosed is an orientation device that may be deployed in a mechanical assembly such as a surveillance camera or enclosure to positively determine the physical orientation and/or attitude (tilt), or any change in such physical orientation and/or attitude, of either the camera or the enclosure, and report that information electronically. The invention includes a sensor that is triggered by the movement of a weighted flag along a shaft caused by gravity or gravity in conjunction with the operation of a spring. As the invention is rotated through 360°, the force of gravity and force of the spring are exerted on the weighted flag, causing it to move along the shaft as the assembly is rotated. Each movement by the flag is detected by the sensor which sends an electronic signal indicating that a predetermined point has been reached. Multiple assemblies may be used, offset from each other, to provide additional and more precise position information.

Abstract: A microphone is enclosed in a semi-sound insulated housing with a jingle bell type device that generates sound in response to a very slight movement and/or vibration of the housing and/or a structure to which the housing is attached. The sensor's sound insulated housing in cooperation with the microphone's adjustable sound sensitivity circuitry is designed for making the microphone responsive exclusively to the internally generated sound of a jingle bell sound generating type device in response to a movement/vibration of the sensor.

Abstract: This invention is an algorithm and method and apparatus for communication in emergency situations and for persons who are disabled. The invention features unique telephone actuation means including overt and covert means both by wired devices and wireless transmission to detect unwanted intruders or the like and to communicate the need for assistance or the existence of emergency or dangerous conditions. Communication activation methods and apparatus usable by disabled or endangered persons and/or unknowingly operable by reason of unauthorized intrusion and the like is provided. Unique motion activated notification devices utilizing disc magnets in tracks associated with magnetic switches are also disclosed.

Abstract: A sensor for use in an interactive electronic device. The sensor comprises a base member having at least one recess formed therein which is partially defined by a peripheral wall thereof. Disposed within the peripheral wall of the base member is at least one switch. Also disposed within the recess is a trigger ball which is freely movable about the peripheral wall of the base member. The sensor is operative to generate at least two different states corresponding to respective positions of the sensor relative to a reference plane. The movement of the sensor relative to the reference plane facilitates the movement of the trigger ball within the recess, with one state being generated when the trigger ball is in contact with the switch and another state being generated when the trigger ball is not in contact with the switch.

Abstract: A motion sensing system device and method which utilize dispersed ultrasonic radiation is disclosed. The system preferably comprises a low profile sensor unit configured to couple to a ceiling position. The sensor unit comprises an ultrasonic transmitter and an ultrasonic receiver and a pair of acoustic reflectors positioned in a transmitting path of the ultrasonic transmitter and a receiving path of the ultrasonic receiver for generating and detecting the ultrasonic radiation in a broadcast field. The acoustic reflectors preferably comprise cones, conical cross-sections and/or combinations thereof which are integral with the ultrasonic transmitter and the ultrasonic receiver and/or are coupled to a housing structure for positioning the acoustic reflectors in the transmitting and/or receiving paths. The sensor unit also preferably comprises a circuit for driving the transmitter and for detecting motion by detecting changes in the receiver signal.

Abstract: An internal condition of a concrete structure is objectively evaluated irrespective of surrounding noise or the shape of a hammer, by placing a vibration sensor in direct contact with a measuring surface so as to directly convert a vibration generated on the measuring surface into a corresponding voltage without the intervention of a medium such as air thereby to quantify the vibration generated on the measuring surface concerned. A structure diagnosis apparatus of the present invention includes a vibration unit for generating an elastic wave in a measuring object of a concrete structure, a vibration detector adapted to be placed in contact with a surface of the measuring object for detecting a component in a predetermined frequency range of an elastic vibration generated on the surface of the measuring object by the vibration unit; and a display device for displaying a maximum amplitude of an output signal of the vibration detector.

Abstract: A vibration detecting apparatus includes a bobbin having a moving path of desired length in an inner periphery of the bobbin; a core movable along the moving path in the inner periphery of the bobbin by vibration applied from exterior or vibration applied to the bobbin; and a coil wound on an outer periphery of the bobbin, the inductance of which being changed in accordance with the shift of the core.

Abstract: A device (10) for receiving date transmitted as impulses through an input transmission body (16) is provided. The device (10) has a vibration sensitive transducer (50) which constitutes part of a floating mass assembly (40) with a pick-up portion (42). The pick-up portion (42) is biased towards a surface of a rigid body that is either the input transmission body (16) or a vibrations transmissive member (151). The assembly (40) has a freedom of movement permitting it to vibrate independently from the rigid body.