Abstract: Aspects of acoustic transducers are described. One aspect is a microelectromechanical (MEMS) transducer comprising a substrate and multiple cantilevered beams. A first cantilevered beam comprises a first protrusion and a first piezoelectric structure, where the first piezoelectric structure comprises a first deflection end and a first fixed end, where the first fixed end is coupled to the substrate, and where the first deflection end is cantilevered away from the substrate. The first cantilevered beam is separated from a second cantilevered beam by a gap. The first protrusion is disposed at the first deflection end and increases a thickness of the first cantilevered beam along the gap at the first deflection end. A second protrusion of the second beam is disposed at a second deflection end and increases a thickness of the second cantilevered beam along the gap at the second deflection end.

Abstract: Systems and techniques are provided for processing audio data. For example, a process can include determining audio context information corresponding to a multi-band bone conduction microphone (BCM), wherein the audio context information is indicative of at least one of noise information or voice information. A process can include generating a control signal indicative of a resonance configuration for one or more resonators of a plurality of resonators included in the multi-band BCM, wherein the resonance configuration is based on the audio context information and corresponds to one or more frequency response adjustments. A process can include transmitting the control signal to the multi-band BCM, wherein the control signal is configured to cause the multi-band BCM to generate a BCM output signal using the resonance configuration.

Abstract: Aspects of the disclosure relate to microelectromechanical systems (MEMS) and associated detection and classification of surface impacts using MEMS systems and signals. One aspect is a device including a memory configured to store an audio signal and a motion signal and one or more processors. The processors are configured to obtain the audio signal, wherein the audio signal is generated based on detection of sound by a microphone, obtain the motion signal, wherein the motion signal is generated based on detection of motion by a motion sensor mounted on a surface of an object, perform a similarity measure based on the audio signal and the motion signal, and determine a context of a contact type of the surface of the object based on the similarity measure.

Abstract: Aspects of the disclosure relate to piezoelectric microelectromechanical systems (MEMS) devices. A piezoelectric MEMS device may include a transducer body including an acoustic cavity extending from a bottom surface to a top surface; a piezoelectric cantilever disposed over the top surface and including a lever region and a sensing region; and an anchor reinforcement member disposed over the piezoelectric cantilever and the transducer body.

Abstract: Aspects of the disclosure relate to piezoelectric microelectromechanical systems (MEMS) devices. A piezoelectric MEMS device may include a transducer body including an acoustic cavity extending from a bottom surface to a top surface and a piezoelectric cantilever disposed over the top surface and comprising a sensing region and a lever region including an embossed structure. The embossed structure comprises a non-planar portion disposed in the lever region and the non-planar portion is offset by 1.5 microns with respect to edges of the lever region. In some aspects, the piezoelectric cantilever is part of a plurality of piezoelectric cantilevers disposed over the top surface of the transducer body.

Abstract: Systems and techniques are provided for detecting bone-conducted sound. A voice accelerometer can include a substrate and a plurality of sensing elements associated with a plurality of frequency bands. Each frequency band can be associated with one or more sensing elements of the plurality of sensing elements having a respective resonance frequency within the frequency band. The voice accelerometer can include a back cavity enclosed by the plurality of sensing elements and the substrate. Each respective sensing element of the plurality of sensing elements can be configured to vibrate in response to a first force corresponding to a bone-conducted sound wave coupled into the voice accelerometer, and a second force corresponding to a back cavity pressure coupling between the plurality of sensing elements, the back cavity pressure coupling based on respective vibration of each sensing element of the plurality of sensing elements.

Abstract: Aspects of the disclosure relate to microelectromechanical systems (MEMS) and A device implementation may include a substrate having a top surface, a bottom surface opposite the top surface, a bottom surface aperture, and a top surface aperture, an acoustic cavity comprising a volume extending from the bottom surface aperture to the top surface aperture, an electroacoustic structure formed at the top surface of the substrate, where the electroacoustic structure comprises an acoustic layer, and where the acoustic layer has a functional range of motion, and a mechanical overstress protection structure formed over the acoustic layer and positioned to contact the acoustic layer when the acoustic layer approaches or exceeds an end of the functional range of motion deflecting away from the substrate.

Abstract: A device comprising: a sensor; and a first circuit configured to detect when an input stimulus to the sensor satisfies one or more detection criteria, and further configured to produce a signal upon detection that causes adjustment of performance of the device; and a second circuit for processing input following detection, wherein the second circuit is configured to increase its power level following detection, relative to a power level of the second circuit prior to detection.

Abstract: Mechanisms for detecting a voltage level on a data communication interface between a slave device and a host device are disclosed. Based on the detected voltage level, the slave device may respond to the host device on the data communication interface at the detected voltage level. The slave device may include a circuit configured to toggle between a first voltage level and a second voltage level to provide one of the first voltage level or the second voltage level corresponding to the detected voltage level on the data communication interface.

Abstract: Systems and techniques are provided for processing audio data. For example, a process can include determining audio context information corresponding to a multi-band bone conduction microphone (BCM), wherein the audio context information is indicative of at least one of noise information or voice information. A process can include generating a control signal indicative of a resonance configuration for one or more resonators of a plurality of resonators included in the multi-band BCM, wherein the resonance configuration is based on the audio context information and corresponds to one or more frequency response adjustments. A process can include transmitting the control signal to the multi-band BCM, wherein the control signal is configured to cause the multi-band BCM to generate a BCM output signal using the resonance configuration.

Abstract: Systems and techniques are provided for detecting bone-conducted sound. A voice accelerometer can include a substrate and a plurality of sensing elements associated with a plurality of frequency bands. Each frequency band can be associated with one or more sensing elements of the plurality of sensing elements having a respective resonance frequency within the frequency band. The voice accelerometer can include a back cavity enclosed by the plurality of sensing elements and the substrate. Each respective sensing element of the plurality of sensing elements can be configured to vibrate in response to a first force corresponding to a bone-conducted sound wave coupled into the voice accelerometer, and a second force corresponding to a back cavity pressure coupling between the plurality of sensing elements, the back cavity pressure coupling based on respective vibration of each sensing element of the plurality of sensing elements.

Abstract: Systems, devices, methods, and implementations related to contact detection are described herein. In one aspect, a system is provided. The system includes a first piezoelectric microelectromechanical systems (MEMS) transducer coupled to configured to generate a first analog signal when the first analog signal is transduced from vibrations propagating through the object. The system includes a second piezoelectric MEMS transducer having configured to generate a second analog signal transduced from acoustic vibrations at a location of the object, and classification circuitry coupled to the output of first piezoelectric MEMS transducer and the output of the second piezoelectric MEMS transducer, where the classification circuitry is configured to process data from the first analog signal and data from the second analog signal, and to categorize combinations of the first analog signal and the second analog signal received during one or more time frames.

Abstract: Aspects relate to mechanisms for detecting a voltage level on a data communication interface between a slave device and a host device. Based on the detected voltage level, the slave device may respond to the host device on the data communication interface at the detected voltage level. In some examples, the slave device may include a circuit configured to toggle between a first voltage level and a second voltage level to provide one of the first voltage level or the second voltage level corresponding to the detected voltage level on the data communication interface.

Abstract: Aspects of the disclosure relate to microelectromechanical systems (MEMS) and associated detection and classification of surface impacts using MEMS systems and signals. One aspect is a device including a memory configured to store an audio signal and a motion signal and one or more processors. The processors are configured to obtain the audio signal, wherein the audio signal is generated based on detection of sound by a microphone, obtain the motion signal, wherein the motion signal is generated based on detection of motion by a motion sensor mounted on a surface of an object, perform a similarity measure based on the audio signal and the motion signal, and determine a context of a contact type of the surface of the object based on the similarity measure.

Abstract: Aspects of the disclosure relate to microelectromechanical systems (MEMS) and associated detection and classification of surface impacts using MEMS systems and signals. One aspect is a device including a memory configured to store an audio signal and a motion signal and one or more processors. The processors are configured to obtain the audio signal, wherein the audio signal is generated based on detection of sound by a microphone, obtain the motion signal, wherein the motion signal is generated based on detection of motion by a motion sensor mounted on a surface of an object, perform a similarity measure based on the audio signal and the motion signal, and determine a context of a contact type of the surface of the object based on the similarity measure.

Abstract: A low noise piezoelectric sensor, such as a piezoelectric acoustic transducer, includes a first conductive layer, a second conductive layer, and a piezoelectric layer between the first conductive layer and the second conductive layer. The piezoelectric layer comprises aluminum scandium nitride (AlScN) having a scandium content of greater than 15%, in which the scandium content and an aluminum content comprises 100% of the aluminum scandium nitride. In this way, the piezoelectric layer (or the sensor including the piezoelectric layer) achieves a dissipation factor of less than about 0.1%.

Abstract: A transducer includes a first piezoelectric layer; and a second piezoelectric layer that is above the first piezoelectric layer; wherein the second piezoelectric layer is a more compressive layer with an average stress that is less than or more compressive than an average stress of the first piezoelectric layer.

Abstract: A device comprising: a sensor; and a first circuit configured to detect when an input stimulus to the sensor satisfies one or more detection criteria, and further configured to produce a signal upon detection that causes adjustment of performance of the device; and a second circuit for processing input following detection, wherein the second circuit is configured to increase its power level following detection, relative to a power level of the second circuit prior to detection.

Abstract: Aspects include piezoelectric acoustic transducers and systems for acoustic transduction. In some aspects, an acoustic transducer is structured with a silicon substrate having a top surface and a bottom surface, where the top surface has a first portion and an edge along the first portion associated with an acoustic aperture. The transducer has a first silicon oxide layer disposed over the first portion of the top surface of the silicon substrate, a polysilicon layer disposed over the first silicon oxide layer, and a second silicon oxide layer disposed over the polysilicon layer. A cantilevered beam comprising a fixed end, a deflection end, a top surface, and a bottom surface, has a first portion of the bottom surface at the fixed end disposed over the second silicon oxide layer, where a second portion of the bottom surface at the deflection end is formed over the acoustic aperture. In some aspects.

Abstract: Aspects include piezoelectric acoustic transducers and systems for acoustic transduction. In some aspects, an acoustic transducer is structured with a silicon substrate having a top surface and a bottom surface, where the top surface has a first portion and an edge along the first portion associated with an acoustic aperture. The transducer has a first silicon oxide layer disposed over the first portion of the top surface of the silicon substrate, a polysilicon layer disposed over the first silicon oxide layer, and a second silicon oxide layer disposed over the polysilicon layer. A cantilevered beam comprising a fixed end, a deflection end, a top surface, and a bottom surface, has a first portion of the bottom surface at the fixed end disposed over the second silicon oxide layer, where a second portion of the bottom surface at the deflection end is formed over the acoustic aperture. In some aspects.