Abstract: This device is provided for a luggage compartment designed to be placed overhead. The compartment comprises a mobile part (4) between an open position and a closed position and a mechanism for acting on said mobile part (4) to promote its closing. Said mobile part (4) presents an opening (14) designed for introducing and retrieving luggage as well as a lower exterior surface (12). The control device comprises detection means reacting when pressure is exerted on a predetermined zone of the lower exterior surface (12) of the mobile part (4) as well as for sending a control signal to the mechanism acting on the mobile part (4) to close the part when pressure is exerted on said detection means. The detection means are disposed at the lower exterior surface (12) of the mobile part (4).

Abstract: A pump assembly for pumping a liquid and a method of controlling the pump assembly. The pump assembly includes a motor coupled to a pump, and an electronic switch assembly electrically connected to the motor to control the current through the motor. The electronic switch assembly includes an electronic switch, a generator that provides a substantially periodic pulsing signal, a circuit control configured to provide a second signal, and decision logic connected to the generator, the circuit control, and the electronic switch. The decision logic receives the periodic pulsing and second signals and generates a control signal that selectively controls the electronic switch based on the periodic pulsing and second signals.

Abstract: Proximity sensing arrangements utilize one or more sensing devices to detect and/or to discern objects that are or become proximate, or are expected to be proximate to a position of interest. For example, one or more capacitive sensors may be distributed to locations about a machine, e.g., attached to, incorporated with, or otherwise associated with a moving or otherwise operating component of the machine. Corresponding control electronics drive each capacitive sensor, using a corresponding excitation signal, as well as process information read from each capacitive sensor to make intelligent proximity related decisions.

Abstract: A method and apparatus is shown for detecting with high sensitivity by allowing the operation of an e-field amplifier without a DC bias resistor shunt with the amplifier input. E-fields produced by an approaching body, or changing E-field of the background, turn on the amplifier from a partial DC bias state with E-field coupling to the power supply of the amplifier. The result is high sensitivity and extremely long battery life. The amplifier is sensitive to transient and quasitatic DC E-field and the AC background signals. The signals are available simultaneously for processing at the output of the amplifier in a DC and AC coupled channel. The resulting signals are passed to a control system.

Abstract: The invention relates to a flexible, resilient capacitive sensor suitable for large-scale manufacturing. The sensor comprises a dielectric, an electrically conductive detector and trace layer on the first side of the dielectric layer comprising a detector and trace, an electrically conductive reference layer on a second side of the dielectric layer, and a capacitance meter electrically connected to the trace and to the conductive reference layer to detect changes in capacitance upon interaction with detector. The sensor is shielded to reduce the effects of outside interference.

Abstract: The disclosure relates to a touch sensing device and method. An embodiment of the disclosed method that comprises starting to count with a counter while charging a sensing point which has distributed capacitance periodically, then transferring the charge on the sensing point to a second capacitor. Next, the voltage on the second capacitor is compared with a reference voltage, and if the former exceeds the latter, the counter stops counting and saving the count value. If the voltage on the second capacitor is less than the reference voltage, the sensing point is judged to determine whether it is in a touching state or in a non-touching state according to the saved count value while discharging the second capacitor, clearing the counter after the discharge, then restarting the method. Using the device and method of this disclosure, the touching sensing action can be tested accurately.

Abstract: A capacitance sensor system and method includes a capacitive sensor as an array of sensor electrodes near the surface of the integrated circuit and charge pump circuits for measuring the capacitance at each sensor electrode. Shield electrodes and unused sense electrodes are used for background capacitance cancellation at each array location. The shield electrodes are switched between the circuit supply potentials in a manner synchronous to the capacitance sensing at the sense electrodes. The improved background capacitance cancellation allows all circuitry to be located outside the sensor array. The capacitance data is used to determine the positions of fingerprint artifacts and other fingerprint features.

Abstract: Natural diamonds can be discerned from imitations, synthetic diamonds and treated diamonds on the basis of their physical qualities. Labs always test several specific characteristics in order to discern natural diamonds from others. One of the tested qualities is electrical conductivity. The invention concerns a method to establish the presence of electrical bulk conductivity. Use is made to this end of the fact that the proximity of an electrically conductive object (gemstone) has an influence on the parasitic capacity of a capacitive probe. The parasitic capacity is also influenced by the dielectric constant of the dielectric. The influence of the proximity of electrically conductive gemstones as opposed to non-conductive gemstones on the parasitic capacity is hereby larger than the influence of the differences in the dielectric constant of the gemstones.

Abstract: A combined passive and active object sensing system (30; 50; 70) employing electric field sensing is described. An electric field sensing transmission electrode (2) generates a first electric field (11, 12, 13) that induces a current in an electric field sensing reception electrode (4). A passive object (10) is sensed from variation in this current. An active object (31; 51; 71) comprises a further electric field sensing transmission electrode (33; 53; 73) and generates a second electric field (35, 36, 37; 55, 56, 57; 75, 76, 77). This may be generated by the active object (31) coupling with and applying a phase shift to the first electric field (11, 12, 13). Alternatively the second electric field (55, 56, 57) may be generated at a different frequency to the first electric field (11, 12, 13). Alternatively the second electric field (75, 76, 77) may be generated by the active object (71) coupling with an alternating magnetic field generated by a coil (172).

Abstract: A method and apparatus are described for interacting with electronic devices through motional commands. The method uses perturbations of the background quasistatic electric fields. The apparatus measures perturbations in electric potential relative to the background. Body movement is recognized by comparing changes in signals over time. Signals collected from sensors are compared with training sets to recognize specified motional commands or gestures. Upon recognizing the commands, the apparatus issues the predetermined response to the motion.

Abstract: Certain embodiments of the present invention provide a proximity detector having a simple configuration and an imaging system including the proximity detector. In an embodiment, a proximity detector mainly comprises: a single electrode mounted on a subject-side end of a movable member; a current feeding device for feeding a constant current to an electrostatic capacitor formed between the electrode and a ground; a discharging device for releasing charge from the electrostatic capacitor at intervals of a certain cycle; a binary-coding device for binary-coding the potential at the electrode relative to a ground based on a threshold; and a smoothing device for smoothing an output signal of the binary-coding device.

Abstract: A fringing capacitance measurement probe and a method for determining a surface dielectric constant. The fringing capacitance measurement probe includes a planarized surface probe element for making interfacial planar contact with a measurement surface, the planarized surface having a metal conductive line portion and an insulating area portion to form a measuring area. The perimeter portion of the metal conductive line portion has a length greater than the perimeter length of the measuring area such that a fringing capacitance of the measurement surface may be determined.

Abstract: In an electrostatic capacitance sensor, an electrode is formed on a base board. The electrode is covered with a resist. A conductive rubber includes a first face and a second face. The first face has a fist area and is opposed to the resist. The second face is opposed to the first face. The second face has a second area which is larger that the first area. A flexible click rubber is attached to the second face of the conductive rubber for providing pressure contact of the conductive rubber with respect to the resist.

Abstract: The novel apparatus permits precise measurements of parasitic capacitances. The apparatus has a test structure and a reference structure, each with two conductor tracks. In the reference structure, the two conductor tracks are always at the same potential. In the test structure, one conductor track is coupled to ground potential and the other conductor track to a different potential. The test structure and the reference structure are connected to a voltage potential and the charge which builds up on the test structure and the reference structure is registered. The parasitic capacitance can be calculated precisely from the charge difference. The conductors of the test structure and of the reference structure are arranged in such a way that each conductor perceives a relationship to capacitive parasitic effects in the same environment.

Abstract: A fringing capacitance measurement probe and a method for determining a surface dielectric constant. The fringing capacitance measurement probe includes a planarized surface probe element for making interfacial planar contact with a measurement surface, the planarized surface having a metal conductive line portion and an insulating area portion to form a measuring area. The perimeter portion of the metal conductive line portion has a length greater than the perimeter length of the measuring area such that a fringing capacitance of the measurement surface may be determined.

Abstract: A method and sensor for determining the ratio of two components in a fluid mixture comprising a test cell in open communication with the fluid mixture and a reference cell containing a desired fluid mixture not in contact with the fluid mixture being tested, said reference and test cells having the same cell geometry. By use of a capacitance divider system, one determines the relative capacitances of said cells correlated with the dielectric constants of the respective fluid mixtures and ascertains the ratio of one component to the other component in the fluid mixture on the basis of the linear and monotonic correlation between the dielectric constant of the mixture at a given temperature and the ratio of one component to the other component. Preferably a mixture of methanol and water is tested such as for use as a feed to a reformer used in supplying hydrogen to a fuel cell. A fixed capacitor equivalent to the reference cell at a given temperature is usually substituted for the latter.

Abstract: The present invention relates to a system for nulling drive feedthrough error in a sensor having first and second drive electrodes which impart vibratory motion to first and second proof masses in response to first and second opposite phase drive signals, and having first and second capacitances defined between the drive electrodes and their associated proof masses. A mismatch between the first and the second capacitance is measured. Drive feedthrough caused by the measured capacitance mismatch is nulled by adjusting the relative amplitudes of the first and second opposite phase drive signals, whereby the ratio of the amplitudes is proportional to the ratio of the first and second capacitances. A servo loop may adaptively effect the ratio of amplitudes.

Abstract: The novel apparatus permits precise measurements of parasitic capacitances. The apparatus has a test structure and a reference structure, each with two conductor tracks. In the reference structure, the two conductor tracks are always at the same potential. In the test structure, one conductor track is coupled to ground potential and the other conductor track to a different potential. The test structure and the reference structure are connected to a voltage potential and the charge which builds up on the test structure and the reference structure is registered. The parasitic capacitance can be calculated precisely from the charge difference. The conductors of the test structure and of the reference structure are arranged in such a way that each conductor perceives a relationship to capacitive parasitic effects in the same environment.

Abstract: A wireless liquid sensing system includes a beverage container and a table top for holding the container. Embedded in the walls and bottom of the container are two electrically conductive plates coupled to a transponder wire coil. A reader radiates an RF signal at a predetermined frequency through a reader antenna. A microprocessor, also coupled to the transponder coil and the two plates, is powered by a rectifier circuit that gains power from then radiated RF signal. The microprocessor amplitude modulates the RF signal in accordance with the amount of liquid in the container. The reader can then detect this modulation with a peak detector to sense the amount of the substance in the container when the transponder antenna is inductively coupled to the reader antenna at the predetermined frequency.

Abstract: An apparatus for detecting seated condition detects whether a passenger is seated on a seat and the location of the passenger if seated. In the apparatus for detecting seated condition, antenna electrodes are provided in the inside the seat so that the electric field generates between the ground and the antenna electrodes. A detecting unit detects a first out put of the electric field in a case that a passenger is not seated and a second output of the electric field in a case that a passenger is seated. A data processing unit corrects the second output based on the first output. Accordingly, the seated condition whether the passenger is seated can accurately be detected.

Abstract: A sensor for detecting RF current flowing in a conductor includes a layer 10 of insulating material with a hole 16 for the passage of the RF conductor 18 in a direction normal to the layer. A plurality of conductive tracks 20, 22 (FIG. 3) on the opposite major surfaces of the layer are selectively joined by a plurality of through-holes each containing conductive material. The conductive material selectively connects the conductive elements 20, 22 to form a plurality of loops (FIG. 4) disposed non-parallel to the layer 10 for inductive coupling to the RF conductor 18.

Abstract: This invention is directed to a method of making a capacitive distance sensor that includes one or more sensor cells each with first and second capacitor plates. The method includes determining an expected range of sizes of objects the sensor will be used to detect and determining a total perimeter value for each of a plurality of capacitor patterns. Each capacitor pattern includes a different arrangement of the first and second capacitor plates and the total perimeter value is the sum of the perimeter values for the first and second capacitor plates. The method selects one of the capacitor patterns based on the expected size of the object and on the total perimeter values determined for the capacitor patterns. The selecting step includes selecting whichever one of the capacitor patterns has the largest total perimeter value if the object is smaller than each of the one or more sensor cells.

Abstract: A fringing-field capacitive liquid level sensor comprising an electrically insulating substrate, having a first and a second pattern of conductive capacitance plates plated on the substrate. Each pattern constitutes a fringing-field capacitor having a capacitance the value of which is both dependent on the liquid level and dependent on the dielectric constant of the liquid. The ratio of the two capacitances, however, is proportional to the liquid level and independent of the dielectric constant of the liquid. The fringing-field capacitive liquid level sensor may be used for measurement of liquids of substantially any dielectric constant without requiring full-scale calibration or knowledge of, and calibration for, dielectric constant of the liquid to be measured. Compensation for tilt angle can be provided through the addition of a second level sensor.

Abstract: A distance sensor has a capacitive element in turn having a first plate which is positioned facing a second plate whose distance is to be measured. In the case of fingerprinting, the second plate is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.

Abstract: A distance sensor has a capacitive element in turn having a first capacitor plate which is positioned facing a second capacitor plate whose distance is to be measured. In the case of fingerprinting, the second capacitor plate is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.

Abstract: A distance sensor has a capacitive element in turn having a first capacitor plate which is positioned facing a second capacitor plate whose distance is to be measured. In the case of fingerprinting, the second capacitor plate is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.

Abstract: A paving material analyzer system is disclosed that uses paving material impedance to determine paving material density. The invention also includes a method for analyzing paving material, in particular, determining paving material density. The paving material density can also be used to determine a percentage of maximum compaction. A paving material analyzer is also disclosed that determines paving material density regardless of moisture presence on the paving material.

Abstract: A sensor for indicating changes in the physical presence of persons or objects and including at least two electrically conductive sheets of material that are spaced mutually apart on an electrically non-conductive carrier sheet or the like. A sensing circuit is also provided for sensing changes in the capacitance between the electrically conductive sheets.

Abstract: A distance sensor has a capacitive element in turn having a first armature which is positioned facing a second armature whose distance is to be measured. In the case of fingerprinting, the second armature is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.

Abstract: An apparatus for detecting seated condition detects whether a passenger is seated on a seat and the location of the passenger if seated. In the apparatus for detecting seated condition, antenna electrodes are provided in the inside the seat so that the electric field generates between the ground and the antenna electrodes. A detecting unit detects a first output of the electric field in a case that a passenger is not seated and a second output of the electric field in a case that a passenger is seated. A data processing unit corrects the second output based on the first output. Accordingly, the seated condition whether the passenger is seated can accurately be detected.

Abstract: A shielded flat-plate proximity/dielectric properties sensor includes a dielectric substrate leaving a planar configuration and a pair of spaced sensing electrodes mounted on one surface of the substrate. A pair of shield electrodes limit the electric field produced by the sensing electrodes. A first shield electrode on the back of the substrate intercepts field lines behind the sensor to prevent detection of objects from behind the sensor. A second shield electrode co-planar with and between the sensing electrodes intercepts field lines very close to the sensor to prevent the dense electric field near the sensor from dominating measurements of objects within the field.

Abstract: A method for measuring axial deviation in a taut-wire alignment system (1) that includes a dynamically grounded resistive wire (2) extending along a longitudinal reference axis and adjacent to elements to be aligned (3). The method comprises applying an AC voltage signal to a measurement electrode provided with a reference electrode, the measurement electrode being arranged in a measurement plane in a holder attached to an element to be aligned (3); carrying out a measurement using a capacitive bridge that includes a first capacitor consisting of the measurement electrode and the wire, as well as a second capacitor, in order to provide a measurement signal representing an axial position of the measurement electrode relative to the taut wire (2) ; and processing the measurement signal to provide data indicating the axial deviation between the element to be aligned (3, 7) and a predetermined alignment position. The method is particularly suitable for aligning elements in linear colliders.

Abstract: A fluid contamination analyzer employs one or more micro-miniature sensors which provide for a substantial reduction in sensor dimensions form prior art dimensions of approximately 2 in.×2 in. to approximately 1 mm×1 mm. The sensors are incorporated into probes for easy lubricant fluid accessibility or alternatively may be employed in an on-line analyzer residing in the fluid flow path. The sensors sense an impedance of the fluid which is a function of its contamination and communicates the impedance to analysis circuitry via either a hard-wired or RF data link. An array of sensors may also be utilized in conjunction with a magnetic field intensity gradient to obtain a particulate distribution across the array. Impedance information, which is indicative of the particulate distribution, is communicated to analysis circuitry individually or in a multiplexed format for fluid contamination analysis.

Abstract: The bulls-eye mid-frequency impedance probe has probe electrodes of a larger surface area that conform to the test surface to provide a very low impedance coupling between the probe and surface, unlike other open end coaxial probes. This probe provides accurate measurement of the dielectric properties of dielectric materials in the mid-frequency range of 10 MHz to 1 GHz on flat and curved solid surfaces, while conforming simple or complex curved surfaces by providing a resilient means between the probe contact surface and the probe box.

Abstract: A capacitance sensor detects the absence/presence of physical matter on a sensing surface of the sensor. The capacitive sensor is a multi-cell sensor wherein each cell has one or more buried, protected, and physically inaccessible capacitor plates. The sensor is physically placed in an environment that is to be monitored for deposition of a particle, vapor, and/or drop of a foreign material on the sensing surface. All cells are initially placed in a startup condition or state. Thereafter, the cells are interrogated or readout, looking for a change in the equivalent feedback capacitance that results from an electrical field shape modification that is caused by the presence of physical matter on the sensing surface. When no such change is detected, the method is repeated for another cell. When a change is detected for a cell, a particle/vapor/drop output is provided.

Abstract: Apparatus for resolving movement of a mass within a defined space utilizes at least one electrode proximate to the space to be observed. An AC signal is applied to the electrode, and the current measured from that electrode and also to any other electrodes included in the system, and which are effectively connected to the ground return of the AC-coupled electrode. A person (or object) to be sensed intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed person, whether or not the person provides a grounding path, and the geometry of the distributed electrodes. Given the nonlinear spatial dependence of the field, multiple electrodes can reliably distinguish among a set of expected cases.

Abstract: In a measuring arrangement for determining the lift of a valve including a cylindrical valve stem member arranged in overlapping telescopic relationship with a stationary cylindrical member so as to be movable relative thereto, one of the cylindrical members has on its surface adjacent the other cylindrical member first and third capacitor structures which are axially spaced, and insulated from, each other and the other is provided on its surface adjacent the one cylindrical member with a second capacitor structure extending axially over the first and third capacitor structures when the valve is in a closed position, all the capacitor structures being electrically connected to a control unit for determining from the capacitance difference between the first and third capacitor structures the position of the valve member.

Abstract: Apparatus and methods for resolving movement of a mass within a defined space utilizes at least one electrode proximate to the space to be observed. An AC signal is applied to the electrode, and the current measured from that electrode and also to any other electrodes included in the system and which are effectively connected to the ground return of the AC-coupled electrode. A person (or object) to be sensed intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed person, whether or not the person provides a grounding path, and the geometry of the distributed electrodes. Given the nonlinear spatial dependence of the field, multiple electrodes can reliably distinguish among a set of expected cases.

Abstract: A quasi-electrostatic sensing system surrounds an electrically conductive mass with an electric field, the magnitude of which is sensed at one or more locations to resolve a property of interest concerning the mass. The object intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed mass, whether or not the mass provides a grounding path, and the geometry of the distributed electrodes. Because the response of the field to an object is a complex nonlinear function, adding electrodes can always distinguish among more cases. In other words, each electrode represents an independent weighting of the mass within the field; adding an electrode provides information regarding that mass that is not redundant to the information provided by the other electrodes.

Abstract: A method for determining the degree of hardening of a hardenable material determines the complex electrical permittivity. The .di-elect cons."(t=0)/.di-elect cons."(t) ratio, where .di-elect cons."(t) is the imaginary part of the complex electrical permittivity .di-elect cons.'(t)-j.di-elect cons."(t), is determined as a measure of the strength of the material at an instant in time t. The .di-elect cons.'max/.di-elect cons.'(t) ratio of the real part of the complex permittivity can also be determined as a measure of the strength. These ratios are similar in shape to the curve of the strengths of the hardenable material with time.

Abstract: A non-contact probe provides information as to relative amplitudes of harmonics of a current or voltage waveform as well as total harmonic distortion. The probe includes a non-contact sensor with an amplifier coupled thereto. Output signals from the amplifier are digitized and analyzed in a programmed processor. Output from the processor provides a display of relative harmonic amplitudes as well as an indicator of total harmonic distortion.

Abstract: The inspection apparatus for inspecting performance of a structure such as stator windings of an electric rotating machine of the invention comprises a probe including a measuring element, an arm unit and a cylinder face circumferential moving apparatus. The arm unit has an arm link section supporting the probe (mainly comprising a leading end link assembly and an arm posture keeping mechanism), an arm housing section (mainly comprising a guide rail) regarding driving of this arm link section, and an arm driving mechanism. The arm driving mechanism causes the leading end link assembly to project from the guide rail at an angle toward a measuring position side of the stator windings relative to the axial direction of the rotor unit, while causing the arm link section to travel along the guide rail. The arm posture keeping mechanism is provided with a link wire and a spring, and maintains a straight arm posture of the leading end link assembly after projection from the guide rail.

Abstract: An ice detector includes a pair of electrodes connected by a pair of leads to a control unit which measures the total impedance between leads to thereby sense and detect the presence of ice and other contaminants formed on top thereof utilizing a comparator circuit. The electrodes are integrated into patch which can be placed at different locations on an aircraft.

Abstract: A method and apparatus for measuring displacement of one location of a structure, relative to another, spaced apart location.

Abstract: A method for resolving presence, orientation and activity of a person within a defined space utilizes at least two electrodes proximate to the space to be observed. A characterization of the position and orientation is obtained by providing a pattern of measurement clusters each associated with a position and an orientation. An AC signal is applied to one electrode, and the current measured from that electrode to any other electrodes included in the system, and which are effectively connected to the ground return of the AC-coupled electrode. A person (or object) to be sensed intercepts a part of the electric field extending between the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed person, whether or not the person provides a grounding path, and the geometry of the distributed electrodes.

Abstract: The present invention relates generally to paving equipment. More particularly, the present invention relates to a paving material density indicator which has a selectively shaped sensor to control at least one of the depth, area, sensitivity and shape of a density determination. The effect on sensor capacitance is measured using a constant current source and is used to determine density of the paving material. The invention is also a method for determining density of paving material and a set of sensors for density determination.

Abstract: A quasi-electrostatic sensing system surrounds an electrically conductive mass with an electric field, the magnitude of which is sensed at one or more locations to resolve a property of interest concerning the mass. The object intercepts a part of the electric field extending between the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed mass, whether or not the mass provides a grounding path, and the geometry of the distributed electrodes. Because the response of the field to an object is a complex nonlinear function, adding electrodes can always distinguish among more cases. In other words, each electrode represents an independent weighting of the mass within the field; adding an electrode provides information regarding that mass that is not redundant to the information provided by the other electrodes.

Abstract: An apparatus for medical diagnosis and/or therapy, includes an electromagnetic obstacle sensor. Due to variations of the ambient temperature and humidity and/or due to the hanging of, for example a cloth around the sensors (16,18), drift of the zero point of the control may occur, so that the approaching of an obstacle by a movable part (6) of the apparatus could be incorrectly interpreted by the apparatus. In order to compensate for such drift there is provided a control unit (25) for automatically controlling the output signal V.sub.o of the receiver (27) back to the zero value in the absence of an object in the vicinity of the movable part (6). This control preferably takes place at a comparatively high speed when a cloth or moisture is moved into the vicinity of the sensors, and at a comparatively low speed upon removal of the cloth or the moisture.

Abstract: The present invention relates to a device for the contactless detection of the position of a moving webs. The web has on one side of the web a detector electrode covering its entire width and on the other side in the area of the web edges transmission electrodes fed by an oscillator in phase opposition, so that the capacitive couplings between the transmission electrodes and the detector electrode respond in opposing fashion to deviations of the web from the central position. The signal received by the detector electrode is processed by a current to voltage converter with a very small input impedance so that the potential of the detector electrode remains at zero, and virtually no capacitive displacement currents flow to a screening electrode In this way, the sensitivity of the measurement array is independent of the web width.

Abstract: A capacitive proximity sensing element, backed by a reflector driven at the same voltage as and in phase with the sensor, is used to reflect the field lines away from a grounded robot arm towards an intruding object, thus dramatically increasing the sensor's range and sensitivity.