285 results about "Impedance sensor" patented technology

Embodiments of the present invention relate generally to wireless medical monitoring. In particular, some preferred embodiments of the present invention provide a wearable compact body sensor capable of wireless data transmission to a mobile internet platform. The body sensor includes a plurality of sensors including, for example, a temperature sensor, a heart rate sensor, a respiratory rate sensor, an impedance sensor, an electrocardiogram (ECG) sensor, and a ballistocardiogram (BCG) sensor. The physiological data collected by the body sensor can be sent to or accessed by a physician or health care provider.

A user-retainable monitoring system is disclosed. At least a pair of sensors is provided in association with a support member. The support member is preferably of a type that may be worn by or at least temporarily implanted in a patient. Possible sensor types include temperature sensors and impedance sensors. Temperature sensors may be used to detect a temperature differential between areas of tissue indicative of pathology. Impedance sensors are used to detect subcutaneous fluid detection. The support member may take the form of a bandage, drain or other structure. Monitor structures as described may have stand-alone utility or be connected to a processor or data recorder to enable various functions.

The present invention provides a method and apparatus for detecting and monitoring obstructive sleep apnea. The apparatus includes an intracardiac impedance sensor to measure intracardiac impedance, a movement sensor to measure an amount of movement of a patient, and a controller operatively coupled to said intracardiac impedance sensor and said movement sensor, said controller adapted to receive at least one of an intracardiac impedance and the amount of movement of the patient and detect obstructive sleep apnea based upon said intracardiac impedance and said movement.

A surface impedance sensor and method are provided. The surface impedance sensor generally includes first and second electrodes, a driver circuit to drive the electrodes at a plurality of driving frequencies, and a detection circuit to measure the impedance across the first and second electrodes for comparison against a plurality of reference profiles. The method generally includes measuring the localized surface impedance for each of a plurality of driving frequencies to generate a measured profile, and correlating the measured profile with a reference profile. The system and method can verify contact with a particular surface and can be used with a variety of host devices, including for example ultrasound delivery devices.

This invention describes the deficiencies of current art for sensitive impedance sensors, particularly capacitive sensors, and describes several circuits that improve measurement of small value capacitances, especially in the presence of noise. It also shows various circuit architectures optimized for different capacitive sensing tasks. The circuits also describe a novel method to linearize a conventional charge-transfer capacitive sense circuit and a novel method to eliminate the effect of stray capacitance in charge-transfer capacitive sensors.

A catheter and patch electrode system is provided for use with an apparatus, such as an ablation generator, having a 4-wire interface for improved impedance measurement. The 4-wire interface includes a pair of source connectors across which an excitation signal is produced and a pair of sense connector wires across which the impedance is measured. The RF ablation generator may also produce an ablation signal across a source wire and an indifferent return patch electrode. The system further includes a cable that connects the generator to a catheter. The catheter includes a shaft having a proximal end and a distal end, with an ablation tip electrode disposed at the distal end. A source lead is electrically coupled to the tip electrode and extends through the shaft to the proximal end where it is terminated. An optional sense lead is also electrically coupled to the tip electrode and extends through the shaft to the proximal end. The system further includes a source return (e.g., skin patch) and a sense return (e.g., skin patch), either or none of which may be combined with the indifferent return, and if used may be placed on opposite sides of the patient for improved performance. The impedance sensor circuit produces an excitation signal across the source connectors, which is then carried to the catheter by the cable, then to the tip electrode, travels through the complex load (tissue volume), and returns to the generator via a patch electrode. The impedance is measured by observing the voltage drop across the sense connectors caused by the excitation signal.

Systems, devices and methods provide for acquiring respiration information. A respiration information device includes timer circuitry to time a plurality of shorter time apertures and a plurality of longer time apertures. A respiration sensor, which may be implemented as a transthoracic impedance sensor, is configured to generate a signal indicative of patient respiration. For each aperture of the plurality of shorter time apertures and for each aperture of the plurality of longer time apertures, an estimated characteristic of the respiration is determined. Respiration metrics are developed using one or both of the estimated respiration characteristics of the shorter time apertures and the estimated respiration characteristics of the longer time apertures.

Systems, devices and methods provide for acquiring respiration information. A respiration information device includes timer circuitry to time a plurality of shorter time apertures and a plurality of longer time apertures. A respiration sensor, which may be implemented as a transthoracic impedance sensor, is configured to generate a signal indicative of patient respiration. For each aperture of the plurality of shorter time apertures and for each aperture of the plurality of longer time apertures, an estimated characteristic of the respiration is determined. Respiration metrics are developed using one or both of the estimated respiration characteristics of the shorter time apertures and the estimated respiration characteristics of the longer time apertures.

Disclosed is an esophageal catheter that is capable of simultaneously measuring impedance, hydrostatic pressure and contact pressure in an esophagus from peristaltic waves, esophageal fluid and the transit bolus in a single test episode. Circumferential impedance sensors include sensing electrodes that are oppositely disposed on the circumferential impedance sensor, and reference electrodes that are also oppositely disposed on the circumferential impedance sensor and interspersed between the sensing electrodes. Accurate impedance measurements can be made in this fashion in a transverse direction in the esophagus. A hydrostatic pressure sensor is disposed at the distal tip of the esophageal probe that has a rigid cover to protect the hydrostatic pressure sensor from contact pressures of the esophagus. In this manner, the hydrostatic pressure sensor can provide purely hydrostatic pressure data from the fluids in the esophagus. Disposed above the hydrostatic pressure sensor, at the distal end of the probe, is an optical contraction sensor that detects both hydrostatic and contact pressure, by detecting the occlusion created by a flexible membrane disposed between an optical source and an optical detector mounted longitudinally in the probe, in response to contractions at the esophagus. The output of the hydrostatic pressure sensor and the optical contraction sensor permits estimations to be made of the contact pressures created by the esophagus.

A medical training simulator includes contact-less sensors and corresponding detection objects, configured to enable sensor data collected during a training exercise to be used to evaluate the performance of the training exercise. The simulator includes a simulated anatomical structure, at least one contact-less sensor, and at least one detection object. During a training exercise, a spatial relationship between the contact-less sensor and the detection object produces data for evaluating performance of the training exercise. Either the contact-less sensor or the detection object is embedded in the simulated physiological structure, while the other is included in either a support for the simulated physiological structure, or as part of a tool used during the training exercise. Many types of contact-less sensors can be employed, including capacitance sensors, impedance sensors, inductive sensors, and magnetic sensors.

A sensor system for a steering wheel of a vehicle includes a first sensor disposed within a first portion of the steering wheel to detect contact with a front left surface of the steering wheel. The sensor system includes a second sensor disposed within a second portion of the steering wheel separate from the first portion to detect contact with a front right surface of the steering wheel. The sensor system also includes a third sensor disposed within the steering wheel to detect contact with a rear surface of the steering wheel. The first, second and third sensors are configured to respectively detect touching of the front left surface, the front right, and the rear surface of the steering wheel by a hand or a non-hand part of an operator of the vehicle. The first, second and third sensors can be complex impedance sensors.

A moisture meter (1) has an LCD display (8) driven by a digital microcontroller (50) which generates digital moisture reading data. Readings are stored as discrete records in files. The microcontroller (51) stores a library of material data and automatically compensates signals from a capacitive / impedance sensor circuit (51) according to both stored material parameter values and sensed temperature. Users may edit the parameter values. A non-removable cover (4) is used at the final stage of production to configure the meter for the nature of interfacing (such as serial port interfacing) required.

Methods and systems for detection of an electric field generated by the human / animal body can include providing a passive antenna system for detecting changes in the ambient electric field due to interaction of the ambient with the charges generated by the human / animal body, and a high impedance sensor that is fixed to the encapsulated wire antenna. The result is a passive human / animal detection system without any moving parts. The antenna can be an encapsulated wire, and the wire length can be chosen according the desired application. For systems that are intended to detect the presence of a human being or animal, the encapsulated wire can have a length of one hundred feet or more, and a grid of wires can be used for detection within an Area of Interest (AOI).

Vertical impedance sensor arrangement including a substrate, a first electrically conductive structure having a first uncovered surface and being arranged in and / or on the substrate, a spacer arranged above the substrate and / or at least partially on the first electrically conductive structure, a second electrically conductive structure having a second uncovered surface and being arranged on the spacer, and capture molecules, which are immobilized on the first and on the second uncovered surface, are set up such that particles to be detected hybridize with the capture molecules. The spacer is formed separately from the substrate, and the thickness of the spacer is defined by means of a deposition method.

The invention provides a system for measuring stroke volume (SV), cardiac output (CO), and cardiac power (CP) from a patient that features: 1) an impedance sensor connected to at least two body-worn electrodes and including an impedance circuit that processes analog signals from the electrodes to measure an impedance signal (e.g. TBEV waveform); 2) an ECG sensor connected to at least two chest-worn electrodes and including an ECG circuit that processes analog signals from the electrodes to measure and ECG signal; 3) an optical sensor connected to a body-worn optical probe and including an optical circuit that processes signals from the probe to measure at least one optical signal (e.g. a PPG waveform) from the patient; 4) a processing system, typically worn on the patient's wrist and connected through a wired interface to the optical sensor, and through either a wired or wireless interface to the TBEV and ECG sensors.

Apparatuses and methods for analyzing particles using an impedance sensor. A flow-through impedance sensor may use two in-line electrodes driven in counter phase. A common sensor electrode may be used to, for example, detect impedance and determine trajectories through the sensor area. The sensor may be used in a wide variety of applications, including but not limited to use with microfluidic devices for determining particle characteristics such as position, velocity, size, and concentration as well as detection of bacterial spores and other biological agents of potential use in warfare and bio-terrorism.

An active matrix electro-wetting on dielectric (AM-EWOD) device includes a plurality of array elements arranged in an array, each of the array elements including array element circuitry, an element electrode, and a reference electrode. The array element circuitry includes an actuation circuit configured to apply actuation voltages to the electrodes, and an impedance sensor circuit configured to sense impedance at the array element electrode to determine a droplet property at the array element. The impedance sensor circuit is operated by perturbing a potential applied to the reference electrode. The AM-EWOD device includes a common row addressing line. The impedance sensor circuit further is operated by supplying voltage signals over the common addressing line to effect both a reset operation and an operation for selecting a row in the array to be sensed. The circuitry isolates the array element from the actuation voltage during operating the impedance sensor circuit.

The present invention provides a non-contact impedance sensor which is mounted on measuring region, the radial section structure of the sensor comprises of four layers, metal tube layer, insulation material layer, electrode array layer and insulation ring layer from outside to inside in turn. At least two electrodes are distributed in one circle on the insulation ring layer whose thickness is less than 1% of external diameter, and electric field intensity between electrode array and metal tube layer is less than breakdown strength of insulation layer. The electrode array is separated with measuring region by insulation ring layer. Two image reconstruction algorithms to realize electrical impedance tomography based on the said sensor are also provided. The present invention provides analytical medel, corresponding sensitivity distribution expression and two rapid imaging methods, the sensor can measuring synchronous same-positional dual-mode impedance, advance mutual fusion of real parts and imaginary part information of impedance distribution, predigest the design and implement of software and hardware of dual-mode measuring system.

Processes and apparatuses are provided for contactless measuring or monitoring in-situ and in real time composition or other electromagnetic impedance correlated properties of liquid or gaseous substances or bulk materials. One or more apparatus may include a resonance type impedance sensor having at least two coils, at least one coil of the at least two coils being at least one excitation coil connectable to at least one alternating current source with frequency sweep, at least one other coil of the at least two coils being at least one sensing coil connectable to at least one data processing system. The one or more methods may include calculating changes in amplitude and resonant frequency induced by electromagnetic interaction between said sensor and object to determine impedance of said object under test; and matching said impedance with predetermined calibration data to determine said chemical or physical properties of said object under test.

Tactile sensors are disclosed that mimic the human fingertip and its touch receptors. The mechanical components are similar to a fingertip, with a rigid core surrounded by a weakly conductive fluid contained within an elastomeric skin. The deformable properties of the finger pad can be used as part of a transduction process. Multiple electrodes can be mounted on the surface of the rigid core and connected to impedance measuring circuitry within the core. External forces deform the fluid path around the electrodes, resulting in a distributed pattern of impedance changes containing information about those forces and the objects that applied them. Strategies are described for extracting features related to the mechanical inputs and using this information for reflexive grip control. Controlling grip force in a prosthetic having sensory feedback information is described. Techniques are described for enhancing the useful force range for impedance sensors by internally texturing the elastomeric skin.

An electrosurgical system and method for performing electrosurgery is disclosed. The electrosurgical system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The electrosurgical system includes an electrosurgical instrument, such as an electrosurgical antenna, knife, forceps, suction coagulator, or vessel sealer. The disclosed system includes an impedance sensor, a controller, dynamic impedance matching network, and an electrosurgical energy generator. The dynamic impedance matching network includes a PIN diode switching array configured to selectively activate a plurality of reactive elements. The disclosed arrangement of reactive elements provides real-time impedance correction over a wide range of impedance mismatch conditions.