Abstract: An electronic device may include one or more ultrasonic temperature sensors. The ultrasonic temperature sensors may be formed in openings or cavities in a housing of the electronic device. The ultrasonic temperature sensors may include ultrasonic transmitters that transmit signals at different ultrasonic frequencies and ultrasonic receivers that receive the transmitted signals. Phase differences between the received ultrasonic signals may be used to determine the speed of sound of ambient air and therefore calculate the temperature of the ambient air. The ultrasonic transmitters and receivers may include piezoelectric micromachined ultrasound transducers (PMUTs). Each transmitter and receiver may be a dedicated transmitter or receiver, or may transmit and receive ultrasonic signals. Each receiver may include an array of PMUTs that receive ultrasonic signals of different frequencies. The PMUTS may be formed on complementary metal-oxide semiconductors (CMOS).

Abstract: A head-mounted device or other electronic device may emit an alternating-current magnetic field. A wireless controller may have alternating-current magnetometers for monitoring the alternating-current field. The wireless controller may also have an accelerometer for measuring the orientation of the controller relative to the Earth's gravity and a direct-current magnetometer for measuring the orientation of the controller relative to the Earth's magnetic field. The alternating-current magnetometers may be three-coil magnetometers located at different locations in a controller housing. Using data from the alternating-current magnetometers, the direct-current magnetometer, the accelerometer, and/or other sensors, the wireless controller can determine the position and orientation of the wireless controller. This information can be wirelessly transmitted to the head-mounted device to control the head-mounted device.

Abstract: An electronic device can include a force and touch sensing system. In one embodiment, an input force sensor device of an electronic device is disclosed.

Abstract: An electronic device can include a force and touch sensing system. In one embodiment, an input force sensor device of an electronic device is disclosed.

Abstract: An electronic device may include one or more low-noise pressure sensors for measuring air pressure. The electronic device may include wireless communications circuitry for communicating with external devices also having pressure sensors. Pressure data gathered by an external device may be used as reference pressure data for the electronic device. For example, if both devices are located in the same building, both pressure sensors will detect similar pressure fluctuations due to doors opening and closing and temperature-control systems turning on and off. By subtracting the reference pressure data from the pressure data gathered by the electronic device, calibrated pressure data may be obtained and may be used to reliably detect vertical displacement changes of the electronic device. In other scenarios, the pressure data may be compared with the reference pressure data to determine whether the two devices are in the same room.

Abstract: An electronic device may include one or more low-noise pressure sensors for measuring air pressure. The electronic device may include wireless communications circuitry for communicating with external devices also having pressure sensors. Pressure data gathered by an external device may be used as reference pressure data for the electronic device. For example, if both devices are located in the same building, both pressure sensors will detect similar pressure fluctuations due to doors opening and closing and temperature-control systems turning on and off. By subtracting the reference pressure data from the pressure data gathered by the electronic device, calibrated pressure data may be obtained and may be used to reliably detect vertical displacement changes of the electronic device. In other scenarios, the pressure data may be compared with the reference pressure data to determine whether the two devices are in the same MOM.

Abstract: A high voltage power supply for a static neutralizer is disclosed. The high voltage power supply includes a resonant converter and a load with an emitter module having an emitter, reference electrode, and a capacitance value. The resonant converter is disposed to have a resonant frequency and an output coupled to the load. The resonant converter generates an output waveform with an amplitude sufficient for generating to ions by corona discharge when the load receives the output waveform. The load is predominantly capacitive when the resonant converter is operating at the resonant frequency.

Abstract: A high voltage power supply for a static neutralizer is disclosed. The high voltage power supply includes a resonant converter and a load with an emitter module having an emitter, reference electrode, and a capacitance value. The resonant converter is disposed to have a resonant frequency and an output coupled to the load. The resonant converter generates an output waveform with an amplitude sufficient for generating to ions by corona discharge when the load receives the output waveform. The load is predominantly capacitive when the resonant converter is operating at the resonant frequency.

Abstract: A directional acoustic receiving system is constructed in the form of a necklace including an array of two or more microphones mounted on a housing supported on the chest of a user by a conducting loop encircling the user's neck. Signal processing electronics contained in the same housing receives and combines the microphone signals in such a manner as to provide an amplified output signal which emphasizes sounds of interest arriving in a direction forward of the user. The amplified output signal drives the supporting conducting loop to produce a representative magnetic field. An electroacoustic transducer including a magnetic field pickup coil for receiving the magnetic field is mounted in or on the user's ear and generates an acoustic signal representative of the sounds of interest.The microphone output signals are weighted (scaled) and combined to achieve desired spatial directivity responses. The weighting coefficients are determined by an optimization process.