Abstract: Systems and methods for indicating the presence of a mobile device within a passenger cabin are provided. A method for indicating the presence of a mobile device within a passenger cabin of a vehicle includes linking a vehicle computing device with the mobile device, determining whether a vehicle ignition is off and whether a vehicle lock has been actuated. The method further includes generating an audible mobile device search signal that is played through a cabin and waiting to receive a response from the mobile device as to whether the mobile device detected the audible mobile device search signal. The method further includes determining whether the mobile device is within the passenger cabin based on whether a response was received from the mobile device and generating a first audible indication when the mobile device is within the passenger cabin.

Abstract: A sound sensor, a hydrophone including the sound sensor, and a pressure balancing device for using for the hydrophone are provided. The hydrophone includes: a sensor including a sensing part and a pressure balancing part; a printed circuit board (PCB) that is electrically connected to the sensor; a case that houses the sensor and the PCB and that has an opening at one side thereof; an elastic membrane that covers the opening of the case; and a signal line that is electrically connected to the PCB to be extended to the outside of the case. The pressure balancing part includes a diaphragm of a thin film and a support that supports the diaphragm. A pressure balancing hole is formed at one side of the pressure balancing part, and at the inside of the pressure balancing part, a channel that is connected to the pressure balancing hole is formed, and a compressible gas is filled in the channel.

Abstract: A disclosed digital sensor includes a pair of piezoelectric sensors that respond to acceleration and pressure in opposite ways, a pair of digital transducer circuits each employing a quantized feedback path to obtain digital sensor signals for the piezoelectric sensors, and a combiner circuit that combines the digital sensor signals to produce a compensated digital output signal. The compensated digital output signal may be a pressure compensated acceleration signal, an acceleration compensated pressure signal, or both. Also disclosed is a signal detection method that includes configuring a pair of piezoelectric membranes in a piezoelectric sensor to respond to acceleration and pressure in opposite ways, and based on their responses, producing at least one of a digital pressure compensated acceleration signal and a digital acceleration compensated pressure signal. The digital signals may be produced in part by applying a quantized feedback signal to at least one of the piezoelectric membranes.

Abstract: A pressure-sensitive switch comprising an electrically-insulating base member having front and back surfaces with a through opening extending between the two at the center of the base member. Two electrodes are mounted on the base member's front surface and each have an electrically-conductive contact surface. A flexible diaphragm has its periphery secured in a fluid-tight manner to the back surface of the base member and is provided with a post connected to the central portion of the diaphragm. The post extends through the base member where an electrically-conductive washer is fixed to it where it extends beyond the front surface of the base member. A fluid-tight cap is secured to the front surface, covering an area above the washer and preventing fluid from entering the switch mechanism. The diaphragm, which is formed with plural corrugations, is exposed to the external pressure.

Abstract: The present invention relates to a vortex bubble removing and cooling system for the electromagnetic shock wave generator in the lithotripter. The vortex bubble-removing and cooling system comprises a water-full cushion (17), a metal diaphragm (14) installed inside the chamber body (27) of the water cushion (17) and a coil (13) which is installed at the backside of the metal diaphragm (14). There is at least one first water nozzle (22) on the side wall of the chamber body (27) and a water suction tube (23) at the center of the chamber body (27). The first water nozzle (22) and the water suction tube (23) form a vortex-generating device. The vortex generated inside the chamber body will scour the surface of the metal diaphragm continuously so as to cool the heat and remove the air bubble. This will make the metal diaphragm be in good working condition and greatly increase the working life of the metal diaphragm and the coil.

Abstract: A solid metallic piston of a fluidborne sound projector is provided with a plurality of parallel spaced fluid passages extending between opposite axial end faces of the piston so as to equalize fluid pressures exerted thereon within a chamber enclosed within an end portion of a conduit having an end wall attached thereto through which a solid piston rod extends from the piston to an acoustical power source from which acoustical energy is mechanically transmitted as displacing forces applied to one of the axial end faces of the piston. Displacement of the piston within the chamber is limited in one axial direction by abutment of the rear end face thereof with the conduit end wall and in the other axial direction by abutment of a larger diameter section of the piston with a forward stop on an annular seal fixed to the conduit end portion, through which a smaller diameter section of the piston extends from the larger diameter section.

Abstract: A hydrophone which is automatically inhibited when the immersion depth exceeds a predetermined threshold by action, on the push element (7) of a switch (6), of a flexible wall that bends under the action of the outside pressure. The hydrophone comprises a tubular body (1) with two chambers (1a, 1b) separated by a partition (2). One of the chambers is closed by a flexible diaphragm (4). Switch (6) is fixed at the center of one of the chambers. Diaphragm (4) can push down on and actuate push element (7) by bending. The body can advantageously consist of two parts that can be screwed onto one another, which allows easier adjustment of the inhibition pressure. A pressure-sensitive reception unit (S) is arranged in the other chamber.

Abstract: Hydrophone which is automatically inhibited when the immersion depth exceeds a predetermined threshold by action, on the push element (7) of a switch (6), of a flexible wall that bends under the action of the outside pressure.

Abstract: A pressure compensated sound transducer is provided wherein compensation and equalization of static ambient pressure variations occurring on the faces of at least one piezoelectric element is achieved by a mensural compensating duct communicating compensating fluid between two reservoirs, each located on an opposite face of a piezoelectric element. One reservoir is formed in the void of the support housing containing at least one piezoelectric element; the remaining reservoir is formed in the void between the housing and a sealed impermeable, compliant boot. The sealed boot prevents contamination of the compensating fluid from the external environment and loss of the compensating fluid to the outside environment.

Abstract: A generally cylindrical hydrophone configuration provides compensation for longitudinal accelerations by placing four identical solid piezoelectric transducer elements along its axis with each transducer element being bonded to a head member, two of which are located generally centrally of the cylindrical housing and fastened thereto and two of which are located near the outside edges of the housing and having slight clearance therewith. Flexible polyurethane boots are clamped to the ends of the housing. The volumes between the centrally disposed and outer transducer head members and between the outer head members and the boots are filled with methyl silicon fluid. Each head member is electrically connected to one side of the electrical output, and the junction between the transducer members is connected to the opposite side, both sides being wired to an electrical contact plate located between the two centrally disposed transducer head members, this volume being filled with electrical potting material.

Abstract: A sound amplification system includes an amplifier and a waterproof microphone. In an exemplary embodiment the microphone includes a transducer within a cavity covered by a resilient waterproof membrane. The system can monitor either the complete frequency range of the microphone or only one or more selected frequency ranges. The system can include one or more noise emitting lures that produce sound in a frequency range corresponding to the one or more selected frequency ranges. The invention also includes a method of waterproofing a miniature microphone.

Abstract: The invention relates to underwater acoustic transmitters intended to be submerged at large depths. It consists in threading the set of annuli forming the transmitter onto an internal tube (303) preferably made from a carbon/resin composite, which supports two end plugs (306, 307) making it possible to relieve the set of annuli of the radial component of the hydrostatic pressure. Furthermore, between the piezoelectric annuli (101) of the transmitter are inserted decoupling annuli (301) which are made as a three-layer structure including a hard and rigid internal layer (201) and two flexible and elastic external layers (202, 203). It makes it possible to increase the transmitting power of these acoustic transmitters.

Abstract: In a flextensinal transducer a drive stack provided inside the oval shell has a strain compensator that has a cylinder and piston. The cylinder is provided in the oval shell, and the piston is stiffly attached to the end of the drive stack. Inside the cylinder, the piston can move along the major axis of the oval shell. When the flextensional transducer is sunk into the water, the oval shell is distorted to extend along the major axis. Then the cylinder and the piston moves relatively to each other to compensate for the distortion.

Abstract: A sonar transducer displaying improved reliability and operating characteristics by employing multiple ceramic stacks, novel support structure and an improved gaseous environment.

Abstract: A piston transducer having a central longitudinal axis and at least one piston member and an active transducer section displaced from one another along the longitudinal axis. Movement of the active transducer section is generally in a plane perpendicular to the longitudinal axis and a series of lever arms couple the movement of the active transducer section into a corresponding axial movement of the piston member and which axial movement is with a uniform velocity across the radiating surface thereof. For two-sided radiation, another piston member and series of levers may be connected to the active transducer section.

Abstract: The present invention relates to a process and transducer for emitting wide and and low frequency acoustic waves in unlimited immersion depth.The invention is applied to tranducers comprising at least one electro-acoustic motor (1) causing any wall 3 of the said waves to vibrate, and a hollow shell 5 enclosing the said motor 1, and delimiting with the said vibrating wall 3 among others, a cavity 7, characterised in that:at least one opening 5, causing cavity 7 to communicate with ambient medium 4, is made in said shell 5;in at least part of the volume of the said cavity 7, at least one flexible bladder 7, is installed;this bladder 8 is filled with a fluid 9 more compressible than fluid 4.

Abstract: An acoustic transducer of the flexural strain gauge type, in which a shell body of oblong section is stressed by a motor along a major axis of this section. A viscoelastic element absorbs the slow deformation of the shell under the effect of submersion. The viscoelastic element exhibits a considerable stiffness at the frequencies of use of the transducer so as to transmit the vibrations from the motor to the shell with adequate efficiency. Such a device makes it possible to manufacture a flexural stain gauge transducer capable of withstanding considerable submersion without the motor fracturing and the efficiency of which is greater than 75%.

Abstract: A pressure compensated hydrophone assembly consists of a hollow mandrel that has an outer surface. The central portion of the outer surface of the mandrel defines a concavity. A flexible, resilient piezoelectric film is wrapped several times around the mandrel. The volume between the inner wrap of the film and the concavity on the outer surface of the mandrel serves as a pressure compensation chamber. The hydrophone is responsive to varying hydrodynamic pressure fields but is substantially inert to acceleration forces, localized impacts and variations in hydrostatic pressure.

Abstract: A leak detecting microphone inserted directly into fluid within a pipe includes a housing having a first end being inserted within the pipe and a second opposed end extending outside the pipe. A diaphragm is mounted within the first housing end and an acoustic transducer is coupled to the diaphragm for converting acoustical signals to electrical signals. A plurality of apertures are provided in the housing first end, the apertures located both above and below the diaphragm, whereby to equalize fluid pressure on either side of the diaphragm. A leak locating system and method are provided for locating fluid leaks within a pipe. A first microphone is installed within fluid in the pipe at a first selected location and sound is detected at the first location. A second microphone is installed within fluid in the pipe at a second selected location and sound is detected at the second location.

Abstract: A high power, low frequency flextensional transducer (50) for underwater use comprises a number of spaced piezo-electric element stacks (53) between opposed inserts (51, 52). A Kevlar (registered trademark) compression band (54) is wound around the stacks and inserts and then partly elliptical plaster formers (56) are attached. A filament wound elliptical GRP flexural shell (57) is then wound around the assembly while controlling the tension so as to provide the required pre-stress on the piezo-electric stacks (53) when cured. After curing the plaster formers (56) are removed. End-plates (16) are attached to the elliptical shell (57) to complete the transducer; the shell (11) having a compression bonded layer (61) of neoprene applied, including a peripheral serrated lip seal (62) to seal against the end-plate (16) while permitting flexing of the shell. A device to provide wide bandwidth performance is also disclosed.

Abstract: A device for mounting an ultrasonic transducer on user equipment for operation in a contaminating, ambient environment. A housing has a forwardly extending, profiled inner surface for promoting focusing along an axis of ultrasonic waves emitted by a transducer mounted against a shoulder of the casing. A chamber adjacent to a backside of the transducer is formed by a rearwardly extending portion of the casing and a cap forming an overlap portion therewith. A bladder disposed in the chamber has a port which vents into the overlap portion such that pressure equalization across the transducer is dynamically maintained. A calibrator offset by known displacement from the transducer provides a reflected wave portion to the transducer such that errors caused by temperature dependency of the velocity of propagation of the ultrasonic waves through the ambient environment can be substantially eliminated.

Abstract: An immersion-resistant housing adapted to receive a vibratable diaphragm spanning the interior of the housing to divide the housing into first and second chambers includes a first port communicating between the first chamber and the exterior environment. The first port is configured as a tubulation. A second port communicates between the second chamber and the external environment. The tubulation has sufficiently small diameter that water entering therein moves essentially as a piston without breakup. The tubulation is configured to have a volume at least equal to that of the first chamber, and a hydrostatic head of about 32 feet of water is necessary before water can be forced into the first chamber. In the preferred embodiment the diaphragm completely seals the housing against direct communication between the two chambers.

Abstract: A transducer assembly providing a conversion between the electrical and sonic energy, the transducer assembly being adapted for operating submerged at great depths in ocean waters. The transducer assembly is formed by a front and back plate which are affixed in one embodiment to the ends of a first mechanically distributed impedance member, a second mechanically distributed impedance member located between the front and the back plate and a transducer of electroacoustical material mechanically coupling the first and second members for imparting sonic vibrations to these members. In a preferred embodiment, the transducer is bonded at one end thereof to the back plate and at the other end thereof to the second member. External hydrostatic pressure present at the front and back plates does not compress the electroacoustical material.

Abstract: A transducer for use in surface ship applications includes a prestress element for providing additional compressive force to an electromechanical driver disposed within the transducer. The transducer includes a shell having inner portions, an electromechanical driver having end portions coupled to inner portions of the shell, and a block prestress element disposed between one of the end portions of the driver and the inner portions of the shell. The block prestress element is fabricated from a shape memory alloy which can be deformed within a first temperature range and reverts back to its original shape when exposed to a temperature above the first temperature range. This characteristic provides for the generation of additional stresses which may be desired for providing protection to the electromechanical driver from unwanted tensile forces.

Abstract: An acoustic source apparatus has a acoustic transducer that is enclosed in substantially rigid and watertight enclosure to resist the pressure of water on the transducer and to seal the transducer from the water. The enclosure has an opening through which acoustic signals pass and over which is placed a resilient, expandable and substantially water-impermeable diaphragm. A net stiffens and strengthens the diaphragm as-well-as constrains the diaphragm from overexpansion or from migrating due to buoyancy forces. Pressurized gas, regulated at slightly above ambient pressure, is supplied to the enclosure and the diaphragm to compensate for underwater ambient pressures. Gas pressure regulated at above ambient pressure is used to selectively tune the pressure levels within the enclosure and diaphragm so that diaphragm resonance can be achieved. Controls are used to selectively fill, as-well-as vent the enclosure and diaphragm during system descent and ascent, respectively.

Abstract: This pressure compensating device for a volume of immersed gas is equipped with mobile or deformable walls and includes an immersed compensation bladder. The bladder is secured in a housing and communicates with the volume to be compensated. It is arranged by mounting means roughly at the level of the volume. According to the invention, the housing mounting means for the compensation bladder are arranged to allow the housing to move vertically relative to the gas volume so as to keep the mean front of the bladder folds at the level of the surfaces to be compensated, as the volume may be immersed to different depths.The housing mounting means include an arm hinged about a horizontal axis, and a spring exerting its force on a cable connected to the hinged arm.Depending on the preferred application, the mobile walls enclosing volume to be compensated consist of the acoustic drives of underwater electroacoustic transducers.

Abstract: A high power, low frequency flextensional transducer for underwater use comprises a number of spaced piezo-electric element stacks between opposed inserts. The stacks are placed on the plane through the major axis of an elliptical flexural shell and the inserts are shaped to conform with the elliptical shape. The stacks are assembled with first tapered supports and complementary tapered slides are wedged between the shell inserts and the tapered supports until a required pre-stress is exerted by the shell on the piezo-electrical stacks. End-plates are attached to the elliptical shell to complete the transducer; the shell having a compression bonded layer of neoprene applied, including a peripheral serrated lip seal to seal against the end-plate while permitting flexing of the shell. A means to provide wide band-width performance is also disclosed. To extend the range of operational depths the cavity within the transducer is filled with a gas whose vapour pressure can be temperature-controlled.

Abstract: A signal sensor automatically compensates for the variations of the static pressure of the medium in which it is placed. The signal sensor comprises one or two assemblies each formed of a piezoelectric sensitive element applied against one face of a flexible plate. The other face of the plate is shielded from the variations of the dynamic pressure to be measured by a material absorbing the vibrations but fairly flexible so as to transmit any variation of the ambient static pressure. This material which may be a porous foam or a fibrous substance impregnated with liquid, fills a tubular apertured sleeve.

Abstract: The apparatus of the present invention detects the resonant frequency of a vibratory member in contact with a fluid. The detection of the resonant frequency enables the device to be used to detect the density of a fluid which it is in contact with and thereby calculate the flow rate of the fluid. The vibratory member is mounted in a housing in such a way that the chambers on either side of the vibratory member have equal volumes. The fluid enters the device through a conduit and then divides into two equal tubes on either side of an extension of a vibratory member extending down these tubes. The apparatus for measuring the resonant frequency of the vibratory member is mounted on the vibratory member and is comprised of a piezoelectric element coupled to a driver circuit in a feedback loop.

Abstract: This invention pertains to the electroacoustic transducer arts and disclo an improved physical construction therefor in which a honeycomb-like member is used to secure both pressure release and thermal transfer for the converting element.

Abstract: This invention relates to a device for maintaining the gas contained in a submerged enclosure in pressure equilibrium with the outside, comprising a plurality of deformable bags which are immersed at the same time as said enclosure which are filled with gas compressed to different pressures and which communicate with said enclosure via a manifold on which they are connected by automatic three-way valves.

Abstract: A hydrophone having a self-contained means for warning an operator that the hydrophone has reached or exceeded a safe design depth limit. The active elements of the hydrophone are bender-type piezoelectric wafers. An internal stop is provided such that in the presence of a hydrostatic pressure that exceeds a safe design limit, the wafers bottom out against the stop. The stop short-circuits the electrical output signals of the wafers, warning the operator that the hydrophone is in danger of destruction.

Abstract: A ring-shell projector capable of simple disassembly and reassembly. The underwater transducer has a driving ring and a pair of flexible diaphragms on either side of the ring with their rims attached to the ring. The ring is formed of an array of electrostrictive elements and spacer elements, each spacer element having a pair of radial, outward extensions. A pair of coupling rings are provided each adapted to be positioned between the rim of one flexible diaphragm and a corresponding array of spacer element extensions to provide sealing engagement between the flexible diaphragms and the driving ring. Besides simplifying the repair of a projector, the improved design is more versatile, allowing a single driving ring to be used with different sets of shells, having different resonance frequencies and/or bandwidths. Moreover, an expensive step in the construction of a ring-shell projector is obviated, namely, the bolt holes in the metal staves and the subsequent custom matching of the shell holes.

Abstract: A tubular acoustic projector for underwater use consists of a ceramic, piezo-electric transducer (21A, 21B) contained in a coaxial, electrically-conductive cylindrical housing (10) whose side wall (11) is thin enough to vibrate with the transducers (21A, 21B). The side wall (11) maintains the transducer under a radial compressive pre-load so as to avoid ceramic failure due to tensile stress. The side wall is sufficiently thermally conductive to dissipate the heat generated in the transducer, in use, to prevent failure of the transducer under the effects of heat. Electrical isolation of the inner and outer surfaces of the transducer is achieved by filling the housing with an insulating liquid.

Abstract: A sensor for acoustic shockwave pulses, such as in lithotripsy, includes a piezo-electric measuring membrane disposed between two coupling membranes. The intervening space between the coupling membranes is filled with a coupling medium for transmitting the acoustic shockwave pulses. The measuring membrane is in a defined condition largely independent of external influences so that flows in the coupling medium or different pressure exertions on the two coupling membranes do not influence the measured signal produced by the measuring membrane.

Abstract: A Tonpilz transducer having head and tail masses with an interposed active transducer section. The transducer unit is positioned within a housing which has a shoulder portion upon which rests a snubber member which extends to a position just behind the head mass. The transducer is supported from the head mass by means of a thin fiberglass tube which extends from the rear of the head mass and engages a flange portion of the snubber member in the vicinity of the housing shoulder. The housing has a waterproof covering as does the head member with the covering of the head member being secured to the covering by means of a removable strap such that the transducer assembly may be disassembled for repair.

Abstract: A mechanism for compensating an underwater transducer for the ambient hydrostatic pressure. The transducer housing includes a quantity of liquid which may be vaporized in the housing volume. The relative volumes of vapor and liquid depend on the temperature, pressure and type of liquid used. A small heater in the liquid increases the temperature of the liquid so that the pressure of the vapor increases and counteracts the increase in hydrostatic pressure at greater depths. The liquid chosen should have a high critical pressure relative to the operating pressure of the transducer.

Abstract: A ruggedized depth transducer for measuring ambient hydrostatic pressure adjacent an acoustic source wherein the transducer includes a housing having a depth sensor mounted therein. The housing further includes a bore for placing the depth sensor in fluid communication with the ambient pressure. Mounted within the housing bore are a series of mechanical filters for attenuating high-intensity pressure spikes generated by the acoustic source from damaging the depth sensor contained within the housing. The mechanical filters allow gradual changes in ambient pressure to pass into the bore and influence the depth sensor.

Abstract: A bladder shaped to conform to the form of the sonar transducer housing of a torpedo in which it is located compensates for volume changes because of temperature changes of the oil which fills the transducer housing. The bladder also compensates for the change in water pressure produced by the depth at which the torpedo is operating. The bladder is sufficiently stiff so that it maintains a predetermined shape substantially midway between its fully extended and fully compressed position during the time that the housing is air evacuated and then filled with oil at near atmospheric pressure. The bladder is thus capable of expanding or contracting to accommodate changes in the volume of the contained oil as the temperature of the oil changes. The bladder is preferably made of a material without substantial spring force or stretch.

Abstract: An underwater transducer in which a ring of piezoelectric ceramic elements vibrates radially in response to an applied voltage. Spacer elements formed of steel are placed between pairs of ceramic elements and used to couple the ring movement to convex diaphragms. Each diaphragm is formed with radially extending fingers, which attach to the spacer elements. A water bladder assembly within the transducer forms a passive internal pressure compensation system. Preferably, the water bladder assembly is attached to the ring in a manner that mechanically decouples the bladder assembly from the ring.

Abstract: The acoustical energy absorbing baffle has a pair of restricted orifice screens rigidly secured in parallel, spaced relation by a lattice stiffener. The screen-stiffener assembly is immersed in a viscous fluid contained within a tank sealed with an elastic diaphragm. Incident acoustical energy is transmitted through the diaphragm and translated into energy absorbing motion of the fluid through the restrictive screens. A compliant mass is acoustically coupled to the fluid to augment fluid particle velocity through the screens and to further absorb energy.

Abstract: This invention is a device that permits a flextensional transducer to function after the flextensional transducer experiences a pressure equal to or greater than the pressure found at the survival depth of prior art flextensional transducers. The foregoing is achieved by not bonding at least one end of the transducer's piezoelectric stack to the transducer's shell and having the other end or ends of the piezoelectric stack held in the vicinity of the transducer's shell by a pair of guide rails, etc. This permits the transducer's shell to move away from at least one end of the piezoelectric stack at pressures equal to or greater than the pressure at which the stack would experience tensile stresses in a conventional flextensional design. Thus, the piezoelectric stack will not fracture since it receives no tensile stress.

Abstract: A piezoelectric audible sound generator having a feedback type piezoelectric transducer, an amplifier, and a phase compensator for adjusting the phase shift due to the combination of a bias resistance of the amplifier and equivalent capacitance of the piezoelectric transducer.

Abstract: A sonar transducer especially adapted for use when subjected to high hydrostatic pressures and extreme mechanical and explosive shock. The sonar transducer includes a conventional casing, ruggedized to withstand high pressures and a hostile environment. The casing is closed on all sides but one. An array of piezoelectric ceramic stacks are suspended inside of the casing and sandwiched between a single front mass and individual rear masses. The single front mass is positioned closest to the open side of the casing. A flexible cover is sealed over the open side of the casing and pressurized oil is placed inside the housing. Appropriate channels are provided to enable the oil to freely flow throughout the interior of the unit, including flowing inside of and about the ceramic stacks. Electrical connections are made with the ceramic stacks to allow external voltages to electrically stress the stacks, and also to allow external sensing of the voltages generated when the stacks are mechanically stressed.

Abstract: A transducer array release and pressure compensation system for releasing a ose cone assembly from a cylindrical housing so as to deploy a plurality of transducer elements and pressure compensate the transducer elements. When hydrostatic pressure is applied to a bladder located within the nose cone assembly, the bladder pulls a release cable so as to release a split ring which secures the nose cone assembly to the cylindrical housing. The application of hydrostatic pressure to the bladder forces air from the nose cone assembly through a compensator airline to the transducer elements so as to pressure compensate the transducer elements.

Abstract: A hydrophone comprising a tubular thin-walled member of a piezoelectric polymer such as polyvinylidene with electrodes covering the interior and exterior surfaces of the tubular member. An elastomeric core is inserted into the interior of the tubular member and then brought into radial compression against the interior surface of the tubular member.