Abstract: An impedance measurement circuit for determining a complex impedance of a capacitive sensor having at least one sense electrode operable in loading mode and at least one guard electrode. The measurement circuit includes: a pulse generator unit for providing a periodic electric measurement signal and a periodic electric guard signal; a signal sensing circuit for sensing a sense current flowing through the at least one sense electrode or the sense electrodes in response to the pulse generator unit measurement signal; and a control and evaluation unit. The control and evaluation unit is configured for determining a complex impedance from the determined sense currents with reference to a complex reference potential.

Abstract: A method of operating a capacitive sensing device that includes a capacitive sensor having at least one sense electrode, a measurement signal source for providing an alternating electric measurement signal with at least three fixed predefined signal frequencies to the at least one sense electrode, and an impedance measurement circuit for determining an unknown complex impedance of the at least one sense electrode from a response to the provided electric measurement signal.

Abstract: A method of detecting a hand positioning on a steering wheel using a sensing system having an electrically conducting signal line on a rim of the steering wheel with a priori knowledge about a relation between a distance of any portion of the signal line from a reference point and information on a position on the rim, and which further includes an electric impedance change of predefined magnitude that is permanently arranged at a predefined position along the signal line, a signal voltage source, and a control and evaluation unit. From a received measurement signal traveling along the signal line and having been reflected by the electric impedance change and by another portion or portions of the signal line, a reference travel time is determined. A position or positions on the rim of the other portion or portions of the signal line can then be determined.

Abstract: A sensing system and method of recognizing a hand gesture established by a sequence of hand touch positionings on an object. The method includes at least steps of: providing to a signal line a time-dependent measurement signal; receiving the measurement signal after being at least partially reflected by at least one portion of the signal line; determining positions on the object of the portions of the signal line that have reflected the measurement signal; comparing an obtained plurality of stored successively determined positions on the object with at least one predefined pattern of successive positions to derive a measure of similarity; and providing an output signal that is indicative of the predefined pattern of successive positions if the derived measure of similarity is lower than a predefined threshold value.

Abstract: A sensing system for hand or body part positioning detection on an object, particularly on a rim of a steering wheel, includes at least one electrically conducting signal line that is arrangeable on a surface of the object with a priori knowledge about a relation between a distance of any portion of the at least one signal line from a reference point and information on a position on the object, a signal voltage source for providing a time-dependent measurement signal to be traveling along the signal line, and a control and evaluation unit. From a received reflected measurement signal, the control and evaluation unit determines a position or positions on the object of a portion or portions of the signal line at least partially reflecting the measurement signal.

Abstract: A sensor arrangement for capacitive detection of an object, including: an electrode arrangement having a heating element as an electrode; a detection device providing a detection signal to a sensor electrode and capacitively detecting the presence of an object near the sensor electrode; a high-side switch connected between a heating power source having a first potential and the heating element; a low-side switch connected between the heating element and a second potential; and a gate controller closing the high-side switch and low-side switch in a heating mode and opening the high-side switch and low-side switch in a detection mode. A decoupling MOSFET is connected between the high-side switch and heating element. The gate controller closes the MOSFET in the heating mode and opens the MOSFET in the detection mode. During the detection mode, the decoupling circuit provides a third potential at a first node between the high-side switch and MOSFET.

Abstract: A capacitive sensor arrangement includes a sensing electrode having a capacitance (Cx) which depends on the presence of an object in a detection space; a measurement device connected to the sensing electrode and configured to detect the capacitance (Cx) of the sensing electrode; and a conducting structure, wherein the capacitance (Cx) of the sensing electrode depends on a potential of the conducting structure. In order to obtain a reliable capacitive measurement, the measurement device is connected to a power supply between a first potential (Vs) and a second potential (GND), the measurement device being connected to the second potential exclusively via the structure.

Abstract: A system for grounding and diagnostics, including a conductive frame for mounting a capacitive sensor. In order to provide a means for ensuring and monitoring a grounded condition of a conductive frame, the system further includes a diagnostics circuit, by which the frame is AC grounded and which has an electric source connected to the frame via a first line and adapted to apply a diagnose signal to the frame via the first line, the diagnostics circuit being connected to the frame by a second line and being adapted to provide at least one quantity that depends on the diagnose signal and on a ground connection of the frame.

Abstract: A method of operating a capacitive sensing device for diagnosing a galvanic connection of at least one guard electrode. The capacitive sensing device includes at least one sense-guard capacitive sensor and a capacitive measurement circuit. The sense-guard capacitive sensor includes a first electrically conductive sense electrode and a first electrically conductive guard electrode and at least a second electrically conductive sense electrode, which is galvanically separated from the first sense electrode, and at least a second electrically conductive guard electrode. Each of the guard electrodes is proximally arranged to at least one of the sense electrodes and is galvanically separated from each of the sense electrodes. The method uses a calculated difference of imaginary parts of complex sense currents resulting from coupling mode measurements between at least two of the sense electrodes for assessing a status of the galvanic connection of the guard electrodes.

Abstract: A capacitive measurement circuit for a capacitive sensing device having a plurality of antenna electrodes includes: a measurement signal voltage source, a remotely controllable switching unit, and a current measurement circuit. The switching unit includes a plurality of ports and switching members that are configured to provide connections between selected ports. The measurement signal voltage source and the current measurement circuit are operatively connected to a distinct port. Each antenna electrode is individually connectable to a distinct port. The switching unit is configured to connect, within a same measurement cycle, each of the antenna electrodes to the voltage output port and the current measurement circuit for loading mode operation. The switching unit is further configured to connect at least one of the antenna electrodes to the voltage output port and at least one other antenna electrode of the antenna electrodes to the current measurement circuit for coupling mode operation.

Abstract: A sensor arrangement for capacitive position detection of a hand on a steering wheel. The sensor arrangement includes: a plurality of capacitive sensors disposed along a detection surface, which is an outer surface of the steering wheel, each sensor having at least one sensor electrode; and a measurement device electrically connected to the sensors. In order to increase the reliability of capacitive hand detection on a steering wheel, the measurement device is adapted to perform a sequence of detection operations, and in each detection operation, to activate at least one sensor by applying a detection signal to its at least one sensor electrode in order to capacitively detect the hand while grounding at least one other sensor by connecting at least one of its sensor electrodes to ground, and to activate different sensors in consecutive detection operations.

Abstract: A method of operating a capacitive sensing device for diagnosing a galvanic connection of at least one guard electrode. The capacitive sensing device includes at least one sense-guard capacitive sensor and a capacitive measurement circuit. The sense-guard capacitive sensor includes a first electrically conductive sense electrode and a first electrically conductive guard electrode and at least a second electrically conductive sense electrode, which is galvanically separated from the first sense electrode, and at least a second electrically conductive guard electrode. Each of the guard electrodes is proximally arranged to at least one of the sense electrodes and is galvanically separated from each of the sense electrodes. The method uses a calculated difference of imaginary parts of complex sense currents resulting from coupling mode measurements between at least two of the sense electrodes for assessing a status of the galvanic connection of the guard electrodes.

Abstract: A sensor arrangement for capacitive position detection of a hand on a steering wheel. The sensor arrangement includes: a plurality of capacitive sensors disposed along a detection surface, which is an outer surface of the steering wheel, each sensor having at least one sensor electrode; and a measurement device electrically connected to the sensors. In order to increase the reliability of capacitive hand detection on a steering wheel, the measurement device is adapted to perform a sequence of detection operations, and in each detection operation, to activate at least one sensor by applying a detection signal to its at least one sensor electrode in order to capacitively detect the hand while grounding at least one other sensor by connecting at least one of its sensor electrodes to ground, and to activate different sensors in consecutive detection operations.

Abstract: A capacitive sensor system that includes: a sensor arrangement with a plurality of capacitive electrodes, each being connected to a corresponding detector line; and a detector device connected to each detector line and configured to detect the capacitance of each electrode by applying a detector signal. The sensor arrangement includes: at least one electrode group having at least two electrodes, each electrode of an electrode group being connected to another electrode via a resistive element so that all electrodes of this electrode group are connected in series; and a diagnose device that is connected, for each electrode group, at least to a first detector line of a first electrode and to a second detector line of a second detector electrode and is configured to apply a diagnose signal via the first and second detector lines and to detect a conductor break based on a response to the diagnose signal.

Abstract: A sensor arrangement for capacitive position detection of an object. In order to provide means for hand detection on a steering wheel which are reliable and have a low complexity, the sensor arrangement includes: a sensor line with a plurality of sensor electrodes connected in series, wherein at least one resistive element is effectively connected in series between each two consecutive sensor electrodes, a measurement device connected via a linear, unbranched first connection to a first terminal of the sensor line, wherein the measurement device is configured to apply a time-dependent first signal to the first terminal and to identify an activated sensor electrode, with an object in its proximity, at least partially based on a first voltage-current relation at the first terminal.

Abstract: A system for grounding and diagnostics, including a conductive frame for mounting a capacitive sensor. In order to provide a means for ensuring and monitoring a grounded condition of a conductive frame, the system further includes a diagnostics circuit, by which the frame is AC grounded and which has an electric source connected to the frame via a first line and adapted to apply a diagnose signal to the frame via the first line, the diagnostics circuit being connected to the frame by a second line and being adapted to provide at least one quantity that depends on the diagnose signal and on a ground connection of the frame.

Abstract: A capacitive sensor system that includes: a sensor arrangement with a plurality of capacitive electrodes, each being connected to a corresponding detector line; and a detector device connected to each detector line and configured to detect the capacitance of each electrode by applying a detector signal. The sensor arrangement includes: at least one electrode group having at least two electrodes, each electrode of an electrode group being connected to another electrode via a resistive element so that all electrodes of this electrode group are connected in series; and a diagnose device that is connected, for each electrode group, at least to a first detector line of a first electrode and to a second detector line of a second detector electrode and is configured to apply a diagnose signal via the first and second detector lines and to detect a conductor break based on a response to the diagnose signal.

Abstract: A capacitive sensor arrangement includes: a sensing electrode having a capacitance (CX) which depends on the presence of an object in a detection space; a measurement device connected to the sensing electrode and configured to detect the capacitance (CX) of the sensing electrode; and a conducting structure, wherein the capacitance (CX) of the sensing electrode depends on a potential of the conducting structure. In order to obtain a reliable capacitive measurement, the measurement device is connected to a power supply between a first potential (VS) and a second potential (GND), the measurement device being connected to the second potential exclusively via the structure.

Abstract: A seat monitoring system for monitoring an occupancy related status of at least one seat inside an automotive vehicle compartment. The seat monitoring system includes a control module mounted within the compartment, and at least one sensor module integrated into the at least one seat. The sensor module has a sensing system for sensing an occupancy related status with respect to the seat. The control module is arranged in wireless communication with the sensor module. The control module has at least three transmitting RF antennas configured to transmit a request signal in at least three directions inside the vehicle compartment; and the sensor module is further configured to receive the request signals from the at least three directions, to determine reception parameters of the request signals, and to transmit an information responsive to the reception parameters to the control module.

Abstract: A capacitive vehicle seat occupancy detection and classification system includes an impedance measurement circuit and a control and evaluation unit. The impedance measurement circuit is configured for providing periodic electrical measurement signals to a capacitive sensor of N different fundamental frequencies, wherein N is a natural number of at least 3, and to determine a complex impedance from each of determined sense currents in the capacitive sensor. The control and evaluation unit is configured to determine a seat occupancy class for each one of the complex impedances determined at the at least N different fundamental frequencies, and to determine a final seat occupancy class derived by a majority decision among the determined seat occupancy classes.