Particle detection device comprising a support, a platform for receiving particles, four beams suspending the platform from the support, such that the platform can be made to vibrate, means for making said platform vibrate at a resonance frequency, means for detecting the displacement of the platform in a direction of displacement. Each beam has a length I, a width L and a thickness e and the platform has a dimension in the direction of displacement of the platform and in which in a device with out of plane mode I?10?L and the dimension of each beam in the direction of displacement of the platform is at least 10 times smaller than the dimension of the platform in the direction of displacement.

A wireless force sensor includes a flexible structure supported opposing a rigid structure with a gap between the flexible structure and the rigid structure. Contact traces on opposing surfaces of the flexible structure and the rigid structure form transmission lines. The contract traces are aligned to contact when a force is applied the flexible structure to cause contact between the traces on the opposing surfaces. Radio-frequency switches modulate a reflected signal from the transmission lines. An antenna receives an interrogation signal transmits the reflected signal.

A wireless pressure sensing unit (20) comprises a membrane (25) forming an outer wall portion of a cavity and two permanent magnets (26,28) inside the cavity. One magnet is coupled to the membrane, and at least one magnet is free to oscillate with a rotational movement. At least one is free to oscillate with a rotational movement. The oscillation takes place at a resonance frequency, which is a function of the sensed pressure, which pressure influences the spacing between the two permanent magnets. This oscillation frequency can be sensed remotely by measuring a magnetic field altered by the oscillation. The wireless pressure sensing unit may be provided on a catheter (21) or guidewire.

Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified. Beneficially a method of determining the state of a rebar without electrical contact is taught.

Aspects of the present disclosure are directed to force sensors. As may be implemented in accordance with one or more embodiments, an apparatus includes a force-responsive component having a resonant frequency, and a circuit that compensates for variations with the force-responsive component. The force-responsive component moves in response to an applied force, in accordance with a spring constant that is susceptible to fluctuation. The compensation circuit determines Brownian motion of the force-responsive component at the resonant frequency based on temperature, and generates an output based on the determined Brownian motion and movement of the force-responsive component. Such an output is indicative of force applied to the apparatus.

Aspects of the present disclosure are directed to force sensors. As may be implemented in accordance with one or more embodiments, an apparatus includes a force-responsive component having a resonant frequency, and a circuit that compensates for variations with the force-responsive component. The force-responsive component moves in response to an applied force, in accordance with a spring constant that is susceptible to fluctuation. The compensation circuit determines Brownian motion of the force-responsive component at the resonant frequency based on temperature, and generates an output based on the determined Brownian motion and movement of the force-responsive component. Such an output is indicative of force applied to the apparatus.

Pressure sensors that may be used in flowrate monitoring or measuring systems, where the pressure sensors may enable simple, low-cost designs that are readily implemented. One example may provide a pressure sensor having a built-in flow path with a dimensional variation. Pressures of a fluid on each side of the dimensional variation may be compared to each other. The measured differential pressure may then be converted to a flowrate through the flow path.

In some embodiments, a sensor includes a microelectromechanical system (MEMS) structure, a cover, and a bump stop. The MEMS structure is configured to move responsive to electromechanical stimuli. The cover is positioned on the MEMS structure. The cover is configured to mechanically protect the MEMS structure. The bump stop is disposed on a substrate and the bump stop is configured to stop the MEMS structure from moving beyond a certain point. The bump stop is further configured to stop the MEMS structure from making physical contact with the substrate. Moreover, the cover is configured to apply a force to the MEMS structure responsive to a voltage being applied to the cover.

In some embodiments, a sensor includes a microelectromechanical system (MEMS) structure, a cover, and a bump stop. The MEMS structure is configured to move responsive to electromechanical stimuli. The cover is positioned on the MEMS structure. The cover is configured to mechanically protect the MEMS structure. The bump stop is disposed on a substrate and the bump stop is configured to stop the MEMS structure from moving beyond a certain point. The bump stop is further configured to stop the MEMS structure from making physical contact with the substrate. Moreover, the cover is configured to apply a force to the MEMS structure responsive to a voltage being applied to the cover.

A sensor system includes one or more rotor antennas on a shaft that moves within a stator bracket one or more of around an axis of the sensor system or along the axis of the sensor system, the one or more rotor antennas configured to communicate sensed data with one or more stator antennas on the stator bracket. Each rotor antenna has a rotor signal trace disposed on an outer rotor side of a dielectric substrate of the rotor antenna and a rotor return trace disposed on the outer rotor side of the dielectric substrate, wherein the rotor signal trace and the rotor return trace are not concentric with respect to each other. The one or more rotor antennas are configured to extend one or more of radially around an outer surface of the shaft of a sensor or along the outer surface of the shaft of the sensor.