Abstract: The invention relates to a method for determining a level of a material interface in a tank, by means of a radar level gauge system comprising a transceiver; a probe for guiding a transmitted electromagnetic signal towards the material interface. The probe comprises a first plurality of reference impedance transitions located above the interface at known physical distances from a reference position, and a second plurality of reference impedance transitions located below the interface at known physical distances from the reference position. The method comprising determining electrical distances to the first and second plurality of reference impedance transitions based on a signal reflected by the reference impedance transition, determining, a first and a second approximation function relating the first and second sets of electrical distance values to the physical distances; and determining the level of the material interface based on the first approximation function and the second approximation function.

Abstract: An apparatus including a sensor array, configured to produce an array output value in response to an environmental stimulus, and a controller, the sensor array including a plurality of sensors and a common output terminal connected to the respective outputs of the sensors, each sensor having first and second electrodes configured to output a respective sensor output value in a particular environment based on the areas of the first and second electrodes and/or the spacing therebetween, the controller configured to control which of the sensors are connected to the common output terminal using respective switches to vary the effective area and/or spacing of the sensor array such that the array output value at the common output terminal, based on the contribution of the respective sensor output values of the connected sensors, is held at a reference value.

Abstract: A 3D Motional Command System (MCS) is disclosed for interactive gaming, computer interfaces, communications, imaging, and geological exploration. The system can perform standoff gesture recognition and also function as touch-screens. E-field sensors and array topologies are disclosed comprised of FET discrete transistors. The designs facilitate the fabrication of high density sensor arrays similar to LCD displays. The system can be used in portable and wearable electronic devices. Uses are for PC computers, portable devices, and gaming systems such as the Wii. Other applications include wireless connection of sensor and audio data from a simple headphone jack output.

Abstract: A device for attaching to an electric power line conductor includes an electrically conductive housing with an opening for accepting the power line conductor that is configured to be grounded to the power line conductor. At least one magnetic core configured to surround the power line conductor and power a power supply electronics module. An ambient air relative humidity measuring device is located within the housing.

Abstract: Capacitive sensors and MEMS elements that can be implemented directly above silicon CMOS electronics are disclosed. A capacitive based sensor is disposed over a first predetermined portion of a wafer that includes at least a first ceramic element providing protection for the final capacitive based sensor and self-aligned processing during its manufacturing.

Abstract: A matric potential sensor (100) arranged to measure the matric potential of a medium and comprising a porous material portion (102a, 102b), arranged to absorb moisture from the medium into which, in use, it is inserted, and an electrode element (100) wherein a non-porous compliant material (606, 608) is provided between the porous material (102a, 102b) portion and the electrode element (100).

Abstract: An apparatus and a method are described for measuring water content and salt concentration in a multiphase fluid flow. A capacitive sensor (6, 7) is arranged in a pipe section (5) through which the multiphase fluid flow passes. A signal generator (10) is connected to the capacitive sensor (6, 7). A first measuring transducer (40) is adapted to measure a voltage across the capacitive sensor, and a second measuring transducer (50) is adapted to measure a current through the capacitive sensor. An output circuit (60) is adapted to generate output signals (70, 72) that indicate the salt concentration and water content in the multiphase fluid flow, based on signals emitted from the first (40) and the second (50) measuring transducer.

Abstract: A humidity sensor includes a humidity detention section, a pad section, and a dam section. The humidity detention section includes a pair of detection electrodes facing each other on a predetermined surface of a substrate and a humidity-sensitive film covering the detection electrodes. The pad section is spaced from the humidity detection section on the surface and covered with a protection gel section. The dam section is located between the humidity detection section and the pad section on the surface. The dam section includes a dam wire that is made from the same material as the detection electrodes and a dam humidity-sensitive film that is made from the same material as the humidity-sensitive film and covers at least part of the dam wire.

Abstract: A data collector associated with a grain bin is in communication with a plurality of capacitive moisture cables hanging within the grain bin. Each capacitive moisture cable includes a plurality of sensor nodes positioned along the moisture cable. Each sensor node includes a sensor node microprocessor and a sensor node memory coupled to a temperature sensor, a reference capacitive sensor and a capacitive moisture sensor. A main controller is in communication with the data collector. The main controller memory is configured in a data structure comprising grain type data, temperature data, raw reference capacitance data, raw moisture capacitance data, node identification data, physical node positional data, and a calculated moisture content for each sensor node. A method of determining moisture contents of grain in a grain bin related to such a system is also included.

Abstract: The moisture measuring method and apparatus determines the moisture content of post-harvest in-shell peanuts. A crystal oscillator generates a high frequency signal that is directed through a selected sample of in-shell peanuts. Capacitance, impedance, and phase change data associated with the sample are generated at (at least) two frequencies. The data is then substituted into a semi-empirical equation to determine the moisture content of the in-shell peanuts.

Abstract: Disclosed herein is a method of interrogating a resonant circuit that includes embedding a resonant circuit into a material, wherein a dielectric of a capacitor of the resonant circuit is the material. The method includes remotely determining the resonant frequency of the electrical circuit with a measurement device, wherein the determining is accomplished automatically. Finally, the method includes remotely automatically determining at least one of an estimated or precise resistance of the resonant circuit, an estimated or precise quality factor of the resonant circuit, and an estimated or precise voltage ratio of the resonant circuit, wherein the voltage ratio is a ratio of a voltage of the energy absorbed by the receiver at resonance and a voltage of the energy absorbed by the receiver at a fixed frequency shift from resonance.

Abstract: A humidity detection sensor includes a lower electrode provided on a board, an upper electrode provided so as to face the lower electrode, a humidity sensing film which is formed at least between the lower electrode and the upper electrode and whose dielectric constant changes in response to humidity, and a protective film provided so as to cover the upper electrode. Each of the upper electrode and the protective film has an opening through which the humidity sensing film is partially exposed to the outside. In the opening, the humidity sensing film is provided so as to reach at least a position higher than the position of the lower surface of the protective film.

Abstract: A method and apparatus for producing particle density map images of fluidised particles by electrical capacitance tomography (ECT) in a fluidized bed apparatus allows for measuring online the liquid content of fluidized particles during the fluidization process and for recalibration of the fluidized particle permittivity during fluidization, allowing for online recalibration of an ECT system when the liquid content of particles changes, such as for fluidized bed drying or granulation processes. Recalibration measurements are made using reference electrodes positioned to measure the capacitance of the densely fluidized particles near the side walls of the fluidized bed. The electrodes of an ECT sensor array may be used to make the recalibration measurements which can be used to provide online liquid content measurement, such as moisture content, for the fluidized particles without stopping out stopping fluidization. The liquid content information may be used for process control.

Abstract: An occupant detection system that includes an electrode arranged proximate to an expected location of an occupant for generating an electric field between the electrode and the occupant proximate thereto. An electrical network coupled to the electrode forms a resonant circuit that includes the occupant as part of the resonant circuit. A controller coupled to the resonant circuit is configured to determine a resonant frequency of the resonant circuit indicative of an occupant presence, and a network signal magnitude at the resonant frequency indicative of a humidity value proximate to the electrode. 7. A method for detecting a vehicle applies an excitation signal to the resonant circuit, determine a resonant frequency of the resonant circuit and determines a humidity value based on a network signal magnitude at the resonant frequency.

Abstract: Contacting a pair of electrodes with soil, applying an alternate current input electric signal to one of the pair of electrodes, comparing a phase of an output electric signal from the other of the pair electrodes with a phase of the input electric signal; and determining the concentration of the ionic solute included in the solvent according to a difference of the phases. The difference of the phases is not dependent on the water content. An electrical conductivity is proportional to a water content and ion concentration, thereby, the water content of soil is available according to the measured electrical conductivity, while determining the ion concentration.

Abstract: A method for calibrating apparatuses for determining the moisture content of products based on capacitive measurements comprises the following operating steps: Inserting a device (1) for simulating the dielectric properties of products in a measuring area of an apparatus (2) to be calibrated; taking a capacitive measurement with the apparatus (2) while the device (1) is inserted in the measuring area; modifying the device (1) settings at least once and taking the capacitive measurement again, for each different setting value; comparing each capacitive measurement taken this way with a corresponding known reference capacitive measurement; calibrating the apparatus (2) based on this comparison.

Abstract: According to one embodiment of the present invention, an electrochemical sensor (10) for detecting the concentration of analyte in a fluid test sample is disclosed. The sensor (10) includes a counter electrode having a high-resistance portion for use in detecting whether a predetermined amount of sample has been received by the test sensor.

Abstract: An embodiment of the present invention is directed to a method for reporting position information. Position information received from a plurality of capacitive sensors in an array of capacitive sensors is adjusted based on predetermined adjustment values to generate adjusted position information. Each predetermined adjustment value is associated with at least one of the plurality of capacitive sensors. A signal representative of the adjusted position information is generated. In another embodiment, the sensitivity of at least one of the capacitive sensors is adjusted based on the position of the at least one capacitive sensor within the array.

Abstract: A method for determining the moisture content of wood (1), including the operating steps of inserting the wood (1) between a first plate and a second plate (3) of a capacitor (4); applying a first signal to the first plate (2) of the capacitor (4) using the plate as a transmitting antenna; detecting on the second plate (3) a second signal induced by the first signal, using the second plate (3) as a receiving antenna; determining from the second induced signal detected, a third reference signal, obtaining a differential signal; determining the components of the differential in phase and in quadrature signals from the first signal; filtering the components of the differential in phase and in quadrature signals to obtain a filtered in phase component and a filtered in quadrature component, which are independent of the frequency of the first signal; and calculating the moisture content of wood (1) based on the value of the filtered in phase and in quadrature components of the differential signal.

Abstract: Two test coupons are utilized in an apparatus, method and design process/structure for determining the moisture content in an electronic circuit board (e.g., a printed circuit board (PCB) or panel). The first coupon has a laminate stack-up with voltage planes separated from each other by dielectric material. These voltage planes include etched clearances with neither plated through holes (PTHs) nor drilled holes extending therethrough. The second coupon is substantially identical to the first coupon except that each of the voltage planes of the first coupon includes PTHs extending through etched clearances corresponding to the etched clearances of the first coupon. In one embodiment, an alarm indicating unacceptably high moisture content is generated if a delta capacitance calculated as a difference between capacitance measurements acquired from the respective coupons is greater than a threshold. Preferably, the alarm notifies a user that at least one aqueous process related to PTH formation is implicated.

Abstract: A moisture sensor, for measuring moisture in a building without leaving visible scars to the building surface, is provided. The moisture sensor includes a flexible carrier carrying an antenna for receiving EM-radiation between 9 kHz and 11 MHz and a resonant circuit including a moisture reactive element. The moisture reactive element includes a hygroscopic electrolyte arranged between a first and a second electrode, wherein the electrolyte in the presence of moisture forms mobile ions and provides a complex impedance at least in response to the alternating voltage, which complex impedance varies with the moisture content of the electrolyte.

Abstract: A mailing system includes a mailing machine having an envelope feed path, a sealing system configured to apply a liquid to an envelope in the envelope feed path, a capacitive sensor located in the envelope feed path downstream from the sealing system, and a controller connected to the capacitive sensor. The sealing system may include a liquid reservoir and a liquid applicator. The capacitive sensor is configured to measure a quantity of liquid on a portion of the envelope applied by the sealing system and to generate a signal based on the measured quantity. The controller is configured to perform an operation based on the measured quantity signal from the capacitive sensor.

Abstract: An exemplary, highly integrated, SPM-based system for measuring the conductivity and/or force of substance under programmable engaging/stretching processes is described. A sample bias is applied across two electrodes. A substance to be measured is sandwiched between them. A first electrode is first brought relative to a second electrode (engaging) in programmable pathways that can be described as stretching distance versus time curves. The process of engaging the electrodes continues until a certain current reached, a certain force reached and whichever case happens first. The electrodes are then separated (stretching) in programmable pathways that can be described as stretching distance versus time curves. A periodic modulation can be applied to the engaging/stretching process to realize different stretch pathways. The sample bias across the electrodes is kept constant or swept in a programmable shape over time, described as a voltage-versus time curve.

Abstract: According to one embodiment of the present invention, an electrochemical sensor (10) for detecting the concentration of analyte in a fluid test sample is disclosed. The sensor (10) includes a counter electrode having a high-resistance portion for use in detecting whether a predetermined amount of sample has been received by the test sensor.

Abstract: This invention is concerned with a method for measuring the canopy rehydration pulse during the period of water application. During the rehydration process water leaks from the trunk xylem tubes into the sapwood extraxyllary region. A water content sensor in this region monitors the magnitude and timing of this leakage water thereby giving a measure of the magnitude and timing of the upward flow of water. The rehydration pulse is quantified by a sequence of measurements of sapwood water content: an initial measurement of water content just prior to water application, then measurement of water content during water application. The difference between the values obtained in the two measurements yields a measure of the leakage water in the extraxyllary region and, in turn, the magnitude and timing of the rehydration pulse. Determination of the onset and termination of the rehydration pulse is used to optimize the duration of water application.

Abstract: A concentric coplanar capacitive sensor includes a charged central disc forming a first electrode, an outer annular ring coplanar with and outer to the charged central disc, the outer annular ring forming a second electrode, and a gap between the charged central disc and the outer annular ring. The first electrode and the second electrode may be attached to an insulative film. A method provides for determining transcapacitance between the first electrode and the second electrode and using the transcapacitance in a model that accounts for a dielectric test piece to determine inversely the properties of the dielectric test piece.

Abstract: In a method for capacitive determination of the moisture content in a gas to be measured, it is provided that a capacitive element (2) brought into contact with a gas to be measured is operated in the manner of an RC oscillator (5) in charge-discharge cycles (27, 28), with the moisture content of the gas to be measured being determined from the time duration of a cycle. To assess measurement errors brought about by contaminants or aging effects, a measure for the time duration of a charging process (27) and a discharging process (28) is determined from output signal (26) of RC oscillator (5) and is processed with the measurement signal for the moisture content into a corrected measurement signal.

Abstract: A humidity sensor having temperature sensing includes a substrate and a RLC (damped resonant) circuit formed in or on the substrate. The RLC circuit comprises a capacitor having a first and a second electrically conductive plate and a moisture sensitive dielectric interposed between the first and second plate. An RL network comprising an inductor and a resistor is coupled to the capacitor and comprises a high relative temperature coefficient of resistance (TCR) portion formed from a first material which is coupled to a low relative TCR portion formed from a second material different from the first material. The RLC circuit can be a series RLC circuit. In another embodiment, the RLC circuit can comprises a parallel RLC circuit.

Abstract: Certain example embodiments of this invention relate to large-area transparent conductive coatings (TCCs) including carbon nanotubes (CNTs) and nanowire composites, and methods of making the same. The ?dc/?opt ratio of such thin films may be improved via stable chemical doping and/or alloying of CNT-based films. The doping and/or alloying may be implemented in a large area coating system, e.g., on glass and/or other substrates. In certain example embodiments, a CNT film may be deposited and then doped via chemical functionalization and/or alloyed with silver and/or palladium. Both p-type and n-type dopants may be used in different embodiments of this invention. In certain example embodiments, silver and/or other nanowires may be provided, e.g., to further decrease sheet resistance. Certain example embodiments may provide coatings that approach, meet, or exceed 90% visible transmission and 90 ohms/square target metrics.

Abstract: The subject matter relates to a circuit arrangement for monitoring the function of a fill level measuring apparatus, and particularly of a vibration level switch, including a first piezo-electric vibration device as a transmitting device, a second piezo-electric vibration device as a receiving device, an oscillator circuit, the input and output of which during normal operation are connected to the vibration devices, the second connections of which devices are at common ground potential, and a monitoring circuit for monitoring the function.

Abstract: A capacitive humidity sensor includes: a humidity sensing element with a humidity sensitive film and electrodes; and a processing circuit. The film has a dielectric constant variable in accordance with moisture. The electrodes detect capacitance of the film and outputs a signal corresponding to the capacitance. The processing circuit processes the signal. The film is made of inorganic material having fine pores for adsorbing the moisture. A diameter of the fine pores is set to be a predetermined diameter so that capillary tube aggregation phenomenon occurs at a predetermined relative humidity. The capacitance of the film has a change rate with respect to the relative humidity. The change rate in case of the relative humidity higher than the predetermined relative humidity is larger than that in case of the relative humidity lower than the predetermined relative humidity.

Abstract: A moisture content sensor for measuring the moisture content of a medium. The sensor includes a probe that injects an electrical signal into the medium. Complex impedance circuitry located between the probe and the electrical signal source allows sensing electronics to generate a signal that represents the moisture content within the medium based on changes in the permittivity of the medium. The complex impedance circuitry minimizes the influence of temperature and conductivity of the medium on the sensed signal. The sensing electronics may be adjusted to optimize the sensor for varying medium conditions and to vary the linearity of the response curve based on volumetric water content of the medium.

Abstract: In some embodiments, a method of monitoring particulates may include one or more of the following steps: (a) receiving the particulates in a particulate flow restrictor, (b) collecting a particulate sample in a body section of the flow restrictor, (c) sensing moisture content of the particulate with a flush mounted capacitive sensor, (d) allowing the particulate to empty out of the flow restrictor through a narrowed opening in a discharge section of the flow restrictor, (e) concentrating the particulate sample at a sensor surface, (f) shielding the sensor from stray electric fields, and (g) inputting the particulate at the funnel opening of the flow restrictor.

Abstract: In some embodiments, a method of monitoring particulates may include one or more of the following steps: (a) receiving the particulates in a particulate flow channel mounted within a chute or conduit, (b) collecting a particulate sample in a body section of the flow channel, (c) sensing moisture content of the particulate with a flush mounted capacitive sensor, (d) allowing the particulate to empty out of the flow channel through an opening in a discharge section of the flow channel, (e) concentrating the particulate sample at a sensor surface, and (f) shielding the sensor from stray electromagnetic fields.

Abstract: A method and system for adjusting characteristics of a relative humidity sensor in order to achieve a desired value of accuracy is presented. A relative humidity sensor charge balance circuit includes a series of sensing capacitors Cx1, Cx2 including a thin porous platinum top plate, a humidity sensitive polyimide dielectric, and two metal bottom plates on a semiconductor substrate; and two fixed oxide capacitances Cref, and C0. Changes in humidity affect the humidity sensitive dielectric thereby causing changes in the sensing capacitive value of the capacitive circuit. The charge in the sensing capacitor and the fixed capacitor C0 can be controlled separately by adjusting and/or trimming the supply voltage using a voltage trimmer; thereby the slope and offset of the relative humidity sensor circuit can be modified and controlled to particular desired values.

Abstract: A system for measuring the moisture content in a bale of hay is provided. An embodiment of the system includes a first pair of electrodes configured to mount in a first position in a bale chamber and at least one additional electrode configured to mount in a second position in the bale chamber. The system also includes a controller having circuitry to obtain a first measurement between the first pair of electrodes while the electrodes are in contact with a bale of hay, and a second measurement between at least one of the first pair of electrodes and the at least one additional electrode while the electrodes are in contact with the bale of hay. The controller includes circuitry to output a signal indicative of the moisture content of the bale of hay as a function of the first and second measurements.

Abstract: An apparatus and a method are described for measuring water content and salt concentration in a multiphase fluid flow. A capacitive sensor (6, 7) is arranged in a pipe section (5) through which the multiphase fluid flow passes. A signal generator (10) is connected to the capacitive sensor (6, 7). A first measuring transducer (40) is adapted to measure a voltage across the capacitive sensor, and a second measuring transducer (50) is adapted to measure a current through the capacitive sensor. An output circuit (60) is adapted to generate output signals (70, 72) that indicate the salt concentration and water content in the multiphase fluid flow, based on signals emitted from the first (40) and the second (50) measuring transducer.

Abstract: An especially simple and economical moisture sensor with temperature compensation is provided. To this end, in addition to a measuring capacitor, a second capacitor is arranged on a window of a motor vehicle, wherein the second capacitor is not affected by the moisture and/or water droplets. For analysis, a differential measurement of the capacitances of the measuring capacitor and of the second capacitor is carried out, from which is determined a degree of wetting of the window not influenced by the window temperature.

Abstract: A sensing unit (100) for sensing a parameter of a medium surrounding a tubular member (110) is disclosed. The sensing unit (100) includes an electronics module (102), a flexible sheet (104) and a shaped member (108). The flexible sheet (104) includes one or more sensing elements (106) that interface with the electronics module (102) to form a sensing circuit for sensing the parameter of the medium. The flexible sheet (104) is formable around the outside of the shaped member (108) to provide an insert (200) for insertion into the tubular member (110). After insertion into the tubular member (110) the insert (200) bears against an inner wall (300) of the tubular member (110) so that the shape of the one or more sensing elements (106) adapts to the shape of the inner wall (300) of the tubular member (110).

Abstract: A system and/or method for sensing the presence of moisture (e.g., rain) and/or other material(s) on a window such as a vehicle window (e.g., vehicle windshield, sunroof or backlite). In certain example embodiments, a plurality of sensing capacitors are supported by a window such as a vehicle windshield, the capacitors each having a different field and/or pattern. A sensing circuit outputs an analog signal that is based on and/or related to the capacitances of one or more of the sensing capacitors. In certain example embodiments, a flexible printed circuit board (PCB) mountable in or on a vehicle window is provided. First and second sensing circuits are formed on opposing sides of the flexible PCB, with each said sensing circuit comprising a plurality of different fractal structures.

Abstract: A soil moisture probe includes a capacitance-type probe and a detection circuit. The probe includes two spaced electrodes on the same side of a printed circuit board (PCB). The electrodes are placed on an inner layer of a multi-layer PCB and the detection circuit may be placed on an outer layer. The PCB also includes a ground plane. The detection circuit generates a sawtooth or triangular wave which is converted to a DC voltage representative of the moisture content of a soil sample into which the probe is inserted. The unique circuit uses the capacitance of the probe as part of a low-pass filter that distorts an oscillator-generated square wave into a saw-tooth or triangular wave. A resistance component of the low-pass filter is adjustable, allowing tuning of the probe and the circuit as needed.

Abstract: A smart water timer which includes a water timer, a receiving unit connected to the water timer, and a moisture sensing unit which is in wireless communication with the receiving unit. The smart water timer can sense when the moisture level in the soil is too moist (based on a user setting) and turn off a water supply to a sprinkler as a result A soil moisture sensing unit is placed in the soil in the area to be watered. The soil moisture sensing unit uses a moisture sensing probe and wirelessly transmits a data signal to the receiver, which is connected to the water timer, indicating whether or not the water timer should be permitted to open a water valve.

Abstract: Systems and methods that evaluate moisture content of the soil through change of capacitance and alternative current. A contact free inductive coupling can be provided between a sensor arrangement associated with the soil, and a reader arrangement (e.g., combination of inductor(s) and capacitor(s)) to determine frequency changes of resulting sinusoidal oscillator. Such frequency change can be correlated with moisture content of the soil.

Abstract: A method for calibrating apparatuses for determining the moisture content of products based on capacitive measurements comprises the following operating steps: Inserting a device (1) for simulating the dielectric properties of products in a measuring area of an apparatus (2) to be calibrated; taking a capacitive measurement with the apparatus (2) while the device (1) is inserted in the measuring area; modifying the device (1) settings at least once and taking the capacitive measurement again, for each different setting value; comparing each capacitive measurement taken this way with a corresponding known reference capacitive measurement; calibrating the apparatus (2) based on this comparison.

Abstract: A method for determining the moisture content of wood (1), comprising the operating steps of: inserting the wood (1) between a first plate and a second plate (3) of a capacitor (4); applying a first signal to the first plate (2) of the capacitor (4) using the plate as a transmitting antenna; detecting on the second plate (3) a second signal induced by the first signal, using the second plate (3) as a receiving antenna; determining from the second induced signal detected, a third reference signal, obtaining a differential signal; determining the components of the differential in phase and in quadrature signals from the first signal; filtering the components of the differential in phase and in quadrature signals to obtain a filtered in phase component and a filtered in quadrature component, which are independent of the frequency of the first signal; and calculating the moisture content of wood (1) based on the value of the filtered in phase and in quadrature components of the differential signal.

Abstract: A method and apparatus for producing particle density map images of fluidised particles by electrical capacitance tomography (ECT) in a fluidised bed apparatus allows for measuring online the liquid content of fluidised particles during the fluidisation process and for recalibration of the fluidised particle permittivity during fluidisation, allowing for online recalibration of an ECT system when the liquid content of particles changes, such as for fluidised bed drying or granulation processes. Recalibration measurements are made using reference electrodes positioned to measure the capacitance of the densely fluidised particles near the side walls of the fluidised bed. The electrodes of an ECT sensor array may be used to make the recalibration measurements which can be used to provide online liquid content measurement, such as moisture content, for the fluidised particles without stopping out stopping fluidisation. The liquid content information may be used for process control.

Abstract: A method, circuit and apparatus for detecting capacitance on a droplet actuator, inter alia, for determining the presence, partial presence or absence of a droplet at an electrode on a droplet actuator by: (a) providing a droplet actuator comprising: (i) a substrate comprising electrodes arranged on the substrate for conducting droplet operations on a surface of the substrate; (ii) a capacitance detection circuit for detecting capacitance at the droplet operations surface at one or more of the electrodes; (b) detecting capacitance at the droplet operations surface at one or more of the electrodes; and (c) determining from the capacitance the presence, partial presence or absence of a droplet at the droplet operations surface at the electrode.

Abstract: This invention is concerned with a method and apparatus to measure soil water content. A sensor electrode assembly comprised of a sensor electrode fixed to a spherical shape is implanted in undisturbed soil at the bottom of a low narrow hole in the soil under evaluation. A second electrode is implanted in adjacent soil. Water is adsorbed on the surface of the sensor electrode in proportion to the water in the soil. Electrical charge layers are present at the sensor electrode/water interface due to dissolved oxygen in the adsorbed water. These charge layers result in an interfacial capacitance whose magnitude varies with the amount of water in the soil. Under the assumption that the capacitance of the second electrode/adjacent soil interface is constant, the change in capacitance across the two wires connected to the two electrodes give a measure of the change in soil water content. Energy flow during this measurement is unidirectional, that is, from the interfacial capacitance to the measuring device.

Abstract: A humidity sensor apparatus and method of forming the same. A substrate can be provided upon which a plurality of humidity sensing components are disposed to form a humidity sensor thereof. Each humidity sensing component generally includes an associated particular parasitic capacitance. This parasitic capacitance is utilized to reduce and/or control a sensitivity and a total capacitance value associated with the humidity sensor without increasing a size of the humidity sensor and/or humidity sensor components (e.g., capacitors).

Abstract: An improved relative humidity sensor apparatus that provides a more accurate measurement of humidity in the presence of water condensation. A series capacitive sensor includes a thin porous platinum top plate, a humidity sensitive polyimide dielectric, and two metal bottom plates on a semiconductor substrate. The two capacitors can be wired in series such that the metal bottom plates form independent, electrically driven connections. The thin top layer can form a top plate. Changes in humidity affect the humidity sensitive dielectric thereby causing changes in the capacitive value. A P-well layer and a P-plus layer can be added at the perimeter of the substrate to create a path for a parasitic capacitance caused by water condensation to connect to one or more connection nodes, thereby preventing erroneous measurements of humidity in the presence of water condensation.