A sensor arrangement is provided, including a first capacitive sensor and a second capacitive sensor. A charge pump is coupled to the first capacitive sensor and to the second capacitive sensor, the charge pump being operable to deliver a positive bias voltage. A differential output has a first terminal coupled to the first capacitive sensor and a second terminal coupled to the second capacitive sensor.

A sensor arrangement is provided, including a first capacitive sensor and a second capacitive sensor. A charge pump is coupled to the first capacitive sensor and to the second capacitive sensor, the charge pump being operable to deliver a positive bias voltage. A differential output has a first terminal coupled to the first capacitive sensor and a second terminal coupled to the second capacitive sensor.

Embodiments of an axle monitoring system of the present invention generally include an oil bath cap plug equipped with a sensor assembly containing one or more power provision components, and an oil level monitor, a humidity/temperature sensor, a vibrational energy detector, and/or a GPS tracking chip, all of which are mounted on a microcircuit board, wherein the sensor assembly is adapted and configured to be fitted inside the axle oil bath cap plug. In various embodiments, information and/or data obtained by the sensor assembly can be transmitted, in raw or processed form, to one or more remote devices. Embodiments of a method of using embodiments of an axle monitoring system of the present invention are also provided.

Embodiments of an axle monitoring system of the present invention generally include an oil bath cap plug equipped with a sensor assembly containing one or more power provision components, and an oil level monitor, a humidity/temperature sensor, a vibrational energy detector, and/or a GPS tracking chip, all of which are mounted on a microcircuit board, wherein the sensor assembly is adapted and configured to be fitted inside the axle oil bath cap plug. In various embodiments, information and/or data obtained by the sensor assembly can be transmitted, in raw or processed form, to one or more remote devices. Embodiments of a method of using embodiments of an axle monitoring system of the present invention are also provided.

Cavitation detection systems and methods may include receiving sensor data from one or more data sources; translating a first format of the sensor data to a second format of the sensor data; transmitting the second format of the sensor data; receiving one or more requests for the second format of the sensor data; transmitting one or more responses that are responsive to the one or more requests; and triggering one or more actions based on the one or more responses.

Disclosed is a frequency-selective signal damper including: a viscous polymer exhibiting non-Newtonian fluid behavior; and hydrogel exhibiting sol-gel phase transition. The viscous polymer exhibits shear thinning in a damping region or a noise region, and the hydrogel has a sol phase in the damping region or the noise region. The viscous polymer is gelatin, and the hydrogel is chitosan.

Disclosed is a frequency-selective signal damper including: a viscous polymer exhibiting non-Newtonian fluid behavior; and hydrogel exhibiting sol-gel phase transition. The viscous polymer exhibits shear thinning in a damping region or a noise region, and the hydrogel has a sol phase in the damping region or the noise region. The viscous polymer is gelatin, and the hydrogel is chitosan.

Method and devices for testing a headphone with increased sensation are provided. The headphone can filter and amplify low frequency audio signals, which are then sent to a haptic device in the headphone. The haptic device can cause bass sensations at the top of the skull and at both ear cups. The testing system can evaluate the haptic and acoustic sensations produced by the headphone to evaluate if they have been properly assembled and calibrate the headphones if necessary.

Method and devices for testing a headphone with increased sensation are provided. The headphone can filter and amplify low frequency audio signals, which are then sent to a haptic device in the headphone. The haptic device can cause bass sensations at the top of the skull and at both ear cups. The testing system can evaluate the haptic and acoustic sensations produced by the headphone to evaluate if they have been properly assembled and calibrate the headphones if necessary.

This disclosure provides systems, methods, and apparatus related to an ultrasonic microphone and an ultrasonic acoustic radio. In one aspect a system includes a transmitter and a receiver. The receiver comprises a membrane. The membrane comprises a single layer or multiple layers of a two-dimensional material. The receiver is operable to receive sound waves in a frequency range, with the frequency range being the ultrasonic frequency range.