Abstract: A touch panel as thin or thick as desired has increased touch sensitivity and decreased sensitivity to water includes. The panel or sensor includes a substrate having first and second surfaces and an edge between the surfaces defining a thickness. First and second pluralities of echelons are arranged on the substrate in first and second arrays along first and second centerlines. Each echelon in the pluralities of echelons is formed at an angle relative to their centerlines. First and second shear transducers are mounted on the edge of the substrate and are configured to generate shear waves in a source wave mode in a direction along their centerlines. The shear waves are reflected at the angle by the one or more of the plurality of echelons in the arrays to a sensing wave or the shear wave is converted to a different wave mode than the source mode. The sensing waves are reflected off of an edge opposing the centerlines and are sensed by the transducers.

Abstract: A touch panel has a substrate having first and second surfaces, and defines a touch surface. A first portion of a touch system includes a first plurality of echelons on the first surface in a first array along a first centerline. Each echelon is formed at an angle to the first centerline, and a first shear transducer assembly on the edge of the substrate that generates a shear wave in a source wave mode in a first direction along the first centerline. A second portion of the touch system includes a second plurality of echelons on the first surface in a second array along a second centerline, each echelon at a second angle to the second centerline. The second centerline is orthogonal to the first. A second shear transducer assembly is mounted on the edge and generates a shear wave in a source wave mode in a second direction along the second centerline. The first sensing mode is different from the second sensing mode.

Abstract: An ultrasonic sensor for detecting the presence or absence of an aerated fluid includes a probe having a first solid portion and a second hollow portion. The probe has a closed end at the hollow portion. The solid portion and the hollow portion define an interface therebetween. A transducer element is mounted to the probe at about the solid portion. The transducer element is configured to transmit an ultrasonic signal through the solid portion into the hollow portion and to receive reflections of the ultrasonic signal to determine the presence or absence of a fluid and/or an aerated fluid.

Abstract: A level sensor includes a substrate having at least one reflective side surface, at least one wave generator on one end of the substrate configured to transmit a wave down the surface of the substrate and a plurality of reflective echelons mounted on the substrate such that each echelon is at an angle relative to reflective side surface. The reflective echelons are configured to convert a wave of a first mode in to a wave of a second mode.

Abstract: A touch panel includes a first plurality of echelons arranged on a substrate along a first centerline at a first angle and a second plurality of echelons arranged on a substrate along a second centerline at a second angle. A first wave generator on an end of the substrate is configured to transmit a first wave along the first centerline of the first plurality of echelons and a second wave generator on an end of the substrate is configured to transmit a second wave along the second centerline of the second plurality of echelons. First and second trapping slots are positioned parallel to their respective plurality of echelons.

Abstract: A liquid level sensor includes a rod having a first portion and a second portion, and a wave generation unit affixed to one end of the rod. The wave generation unit generates a wave group that propagates in at least a shear order and a flexural order, and the frequency of the shear wave is based on the diameter of the rod.

Abstract: An ultrasonic liquid-height detector employs conductive rods extending from a housing, and corresponding transducers, into a liquid, where elastic seals surround the rods at their exit point from the housing. Acoustic crosstalk between the rods through the seals and the housing (rather than through the liquid) is minimized by displacing the seals from each other as measured through the housing to increase a path length through the housing so that the crosstalk energy is delayed with respect to the direct energy indicating liquid height. A sampling window is positioned to sample transmitted sound across the rods at a time before the arrival of the crosstalk energy.

Abstract: An ultrasonic sensor detects the presence or absence of a fluid in contact with the sensor and a level of fluid along the sensor. The sensor includes a first probe having a. transducer element operably connected thereto. The transducer element is configured to transmit an ultrasonic signal through the first probe, A second probe has an other than straight shape. The second probe has a transducer element operably connected thereto that is configured to receive the ultrasonic signal transmitted by the first probe to determine the presence or absence of a fluid and when present, the location of fluid along the second probe. The other than straight shape of the second probe increases the path length of the received signal to increase the resolution and accuracy of sensing the presence or absence of the fluid, and when present, the resolution and accuracy of a location along the second probe at which the fluid is present.

Abstract: A liquid level sensor includes a rod having a first portion and a second portion, and a wave generation unit affixed to one end of the rod. The wave generation unit generates a wave group that propagates in at least a shear order and a flexural order, and the frequency of the shear wave is based on the diameter of the rod.

Abstract: An ultrasonic sensor for detecting the presence or absence of an aerated fluid includes a probe having a first solid portion and a second hollow portion. The probe has a closed end at the hollow portion. The solid portion and the hollow portion define an interface therebetween. A transducer element is mounted to the probe at about the solid portion. The transducer element is configured to transmit an ultrasonic signal through the solid portion into the hollow portion and to receive reflections of the ultrasonic signal to determine the presence or absence of a fluid and/or an aerated fluid.

Abstract: An ultrasonic liquid-height detector employs conductive rods extending from a housing, and corresponding transducers, into a liquid, where elastic seals surround the rods at their exit point from the housing. Acoustic crosstalk between the rods through the seals and the housing (rather than through the liquid) is minimized by displacing the seals from each other as measured through the housing to increase a path length through the housing so that the crosstalk energy is delayed with respect to the direct energy indicating liquid height. A sampling window is positioned to sample transmitted sound across the rods at a time before the arrival of the crosstalk energy.

Abstract: An ultrasonic sensor detects the presence or absence of a fluid in contact with the sensor and a level of fluid along the sensor. The sensor includes a first probe having a. transducer element operably connected thereto. The transducer element is configured to transmit an ultrasonic signal through the first probe, A second probe has an other than straight shape. The second probe has a transducer element operably connected thereto that is configured to receive the ultrasonic signal transmitted by the first probe to determine the presence or absence of a fluid and when present, the location of fluid along the second probe. The other than straight shape of the second probe increases the path length of the received signal to increase the resolution and accuracy of sensing the presence or absence of the fluid, and when present, the resolution and accuracy of a location along the second probe at which the fluid is present.

Abstract: A system for detecting a presence of a liquid within a receptacle includes a sensor and a processor. The sensor includes a transmitting probe and a receiving probe positioned within the liquid receptacle. The transmitting probe includes a first transducer and the receiving probe includes a second transducer. The processor is in electrical communication with the first and second transducers and monitors the first and second transducers to determine the presence and level of the liquid within the liquid receptacle based on a time between generation of a first extensional wave by the first transducer and reception of a second extensional wave by the second transducer.

Abstract: A circuit for an acoustic wave switch or sensor having a resonant acoustic wave cavity detects a touch or sensed event using a time domain approach. The circuit includes a controller that drives an acoustic wave transducer to generate a resonant acoustic wave in the acoustic wave cavity during a first portion of a sampling cycle. In a second portion of the sampling cycle, the controller monitors the time that it takes for the acoustic wave signal from the transducer to decay to a predetermined level. Based on the decay time, the controller detects a sensed event, such as a touch on the acoustic wave switch/sensor.

Abstract: A system for detecting a presence of a liquid within a receptacle includes a sensor and a processor. The sensor includes a transmitting probe and a receiving probe positioned within the liquid receptacle. The transmitting probe includes a first transducer and the receiving probe includes a second transducer. The processor is in electrical communication with the first and second transducers and monitors the first and second transducers to determine the presence and level of the liquid within the liquid receptacle based on a time between generation of a first extensional wave by the first transducer and reception of a second extensional wave by the second transducer.

Abstract: Certain embodiments provide an acoustic wave touch bar system and method of use. Certain embodiments include a bar having two portions of reduced cross-section forming an acoustic cavity in the portion of the bar between the reduced cross-sections. The system includes an acoustic wave transducer positioned on the acoustic wave cavity, wherein the transducer generates an acoustic standing wave that is substantially trapped in the acoustic cavity. The system also includes a circuit coupled to the transducer and responsive to a change in an output of the transducer to detect a touch on a touch surface of the bar. The circuit may be a programmable and/or adaptive circuit, for example. The circuit may detect a change in an exponentially decaying response of the transducer indicating that the touch surface of the bar has been touched.

Abstract: An acoustic wave switch includes a substrate with an acoustic wave cavity formed therein such that the mass per unit area of the acoustic cavity is greater than the mass per unit area of the substrate adjacent the cavity. A transducer is mounted on the acoustic cavity for generating an acoustic wave that is substantially trapped in the cavity. A touch on the touch surface of the acoustic wave cavity absorbs acoustic wave energy and produces a detectable change in the impedance of the transducer. Various feedback mechanisms can be employed to provide a user with a tactile, audible and/or visual response indicating actuation of the switch by a touch.

Abstract: An individual acoustic wave switch includes a body with a top section having an acoustic wave cavity formed therein and a base section extending downwardly from the top section. An acoustic wave transducer is mounted adjacent to a surface of the acoustic wave cavity opposite the touch surface thereof so as to generate an acoustic wave in the acoustic wave cavity and to pick up a signal representing the acoustic wave energy in the cavity. The acoustic wave switch is readily mounted in an aperture of a substrate through which the base of the switch extends.

Abstract: A circuit for an acoustic wave switch or sensor having a resonant acoustic wave cavity detects a touch or sensed event using a time domain approach. The circuit includes a controller that drives an acoustic wave transducer to generate a resonant acoustic wave in the acoustic wave cavity during a first portion of a sampling cycle. In a second portion of the sampling cycle, the controller monitors the time that it takes for the acoustic wave signal from the transducer to decay to a predetermined level. Based on the decay time, the controller detects a sensed event, such as a touch on the acoustic wave switch/sensor.

Abstract: An acoustic wave switch includes a substrate with an acoustic wave cavity formed therein such that the mass per unit area of the acoustic cavity is greater than the mass per unit area of the substrate adjacent the cavity. A transducer is mounted on the acoustic cavity for generating an acoustic wave that is substantially trapped in the cavity. A touch on the touch surface of the acoustic wave cavity absorbs acoustic wave energy and produces a detectable change in the impedance of the transducer. The acoustic wave switch has a high Q so as to enable a touch to be detected by extremely simple, low-cost circuitry. The acoustic wave switch of the present invention is rugged, explosion proof, operates in the presence of liquids and other contaminants, has a low power consumption and can be incorporated and integrally formed in a wall of a housing for a device.