A robotic cleaning appliance includes a housing to which is coupled a surface treatment item and a sensor assembly with first and second transducers and an acoustic interface. The first sonic transducer transmits sonic signals through an acoustic interface and out of a first acoustic opening toward a surface beneath the robotic cleaning appliance. The sonic signals reflect from the surface as corresponding returned signals received by the second sonic transducer via a second acoustic opening port of the acoustic interface. A first annular ring is defined around the first acoustic opening port and a second annular rings is defined around the second acoustic opening port. The annular ring attenuate direct path echoes between the acoustic opening ports. The first and second acoustic opening ports are coupled the first and sonic transducers, respectively, via first and second horns; and the horns are tilted from orthogonal with the surface.

A proximity alarm device includes a control unit, an amplifying unit, an output terminal, a ground terminal, a detection unit, and a determining apparatus. The control unit receives an input of a referencing signal. An output of the control unit is electrically connected to the amplifying unit. An output of the amplifying unit is electrically connected to an output terminal. The ground terminal is electrically connected to a ground. The output of the amplifying unit is electrically connected to the detection unit. An output of the detection unit is electrically connected to the determining apparatus. Then, the determining apparatus compares a detection signal detected by the detection unit and a determination reference signal with each other.

A proximity alarm device includes a control unit, an amplifying unit, an output terminal, a ground terminal, a detection unit, and a determining apparatus. The control unit receives an input of a referencing signal. An output of the control unit is electrically connected to the amplifying unit. An output of the amplifying unit is electrically connected to an output terminal. The ground terminal is electrically connected to a ground. The output of the amplifying unit is electrically connected to the detection unit. An output of the detection unit is electrically connected to the determining apparatus. Then, the determining apparatus compares a detection signal detected by the detection unit and a determination reference signal with each other.

A method of operating a sound generation mechanism includes determining a temperature of the sound generation mechanism, identifying a resonant frequency of the sound generation mechanism associated with the determined temperature, and communicating an excitation frequency to the sound generation mechanism. The excitation frequency is selected in response to the resonant frequency associated with the determined temperature. The sound generation mechanism is operated to produce one or more sounds.

An ultrasonic transducer including a membrane film and a perforated baseplate. The baseplate can have a conductive surface with a plurality of perforations formed through the baseplate. The membrane film can have a conductive surface and be positioned under tension proximate to the perforations formed through the baseplate. The tension of the membrane film can be controlled to provide a restoring force to counteract the moving mass of the membrane film, and the moving mass of air in the perforations of the baseplate. By selecting the diameter(s) of the perforations of the baseplate, the thickness of the baseplate, the thickness of the membrane film, the tension of the membrane film, and/or the bending stiffness of the membrane film, a wide bandpass frequency response of the ultrasonic transducer centered at an ultrasonic frequency of interest can be obtained and tailored to a desired application.

Embodiments include a primary short circuit (PSC) coupled to a primary side of a transformer and a dampening element, coupled to a transducer coupled to a secondary side of the transformer, configured to dampen a received signal during a portion of a reverberation period. The PSC and the dampening element may be activated substantially simultaneously. Activation of the PSC circuit mitigates a parallel resonance otherwise arising, in part, in the transducer, but, increases the received signal by a DC shift voltage. The dampening element dampens the DC shift voltage. The received signal may be dampened prior to amplification of the received signal by an amplifier. The dampening facilitates earlier and more precise measurement, during the reverberation period, of at least one operating characteristic for the PAS sensor. Another embodiment prevents the DC shift voltage by selectively activating the PSC within a determined time of a zero-crossing of a given signal.

An ultrasonic transducer including a membrane film and a perforated baseplate. The baseplate can have a conductive surface with a plurality of perforations formed through the baseplate. The membrane film can have a conductive surface and be positioned under tension proximate to the perforations formed through the baseplate. The tension of the membrane film can be controlled to provide a restoring force to counteract the moving mass of the membrane film, and the moving mass of air in the perforations of the baseplate. By selecting the diameter(s) of the perforations of the baseplate, the thickness of the baseplate, the thickness of the membrane film, the tension of the membrane film, and/or the bending stiffness of the membrane film, a wide bandpass frequency response of the ultrasonic transducer centered at an ultrasonic frequency of interest can be obtained and tailored to a desired application.

A method and circuit for controlling a multi-use horn by a bus are disclosed. The circuit comprises a bus signal receiving and transmitting unit used for receiving and transmitting a horn control instruction from a vehicle-mounted computer controller by the bus, a control unit used for generating a horn sounding signal adapting to a current scene according to the horn control instruction, and a horn sounding unit used for making sounds according to the horn sounding signal. By adoption of the method and circuit, the horn is connected to the vehicle-mounted computer controller by the bus and is controlled by the vehicle-mounted computer controller to make sounds, and thus, sound requirements for various horns for different uses on vehicles and engineering machines are met.

Embodiments include a primary short circuit (PSC) coupled to a primary side of a transformer and a dampening element, coupled to a transducer coupled to a secondary side of the transformer, configured to dampen a received signal during a portion of a reverberation period. The PSC and the dampening element may be activated substantially simultaneously. Activation of the PSC circuit mitigates a parallel resonance otherwise arising, in part, in the transducer, but, increases the received signal by a DC shift voltage. The dampening element dampens the DC shift voltage. The received signal may be dampened prior to amplification of the received signal by an amplifier. The dampening facilitates earlier and more precise measurement, during the reverberation period, of at least one operating characteristic for the PAS sensor. Another embodiment prevents the DC shift voltage by selectively activating the PSC within a determined time of a zero-crossing of a given signal.

A micro-machined ultrasonic transducer is proposed. The micro-machined ultrasonic transducer includes a membrane element for transmitting/receiving ultrasonic waves, during the transmission/reception of ultrasonic waves the membrane element oscillating, about an equilibrium position, at a respective resonance frequency. The equilibrium position of the membrane element is variable according to a biasing electric signal applied to the membrane element. The micro-machined ultrasonic transducer further comprises a cap structure extending above the membrane element; the cap structure identifies, between it and the membrane element, a cavity whose volume is variable according to the equilibrium position of the membrane element. The cap structure comprises an opening for inputting/outputting the ultrasonic waves into/from the cavity. The cap structure and the membrane element act as tunable Helmholtz resonator, whereby the resonance frequency is variable according to the volume of the cavity.