A capacitance measurement circuit for determining a capacitance of a guard-sense capacitive sensor includes a microcontroller that uses a combination of several synchronized PWM outputs for generating a low distortion sine wave. The sine wave is used as a guard voltage for the guard electrode of the capacitive sensor. The capacitance value of an unknown capacitor is measured by impinging the guard voltage on the sense electrode of the capacitive sensor by a modified sigma-delta modulator unit. The digital output of the sigma-delta modulator unit is first multiplied by an XOR gate before being routed into a decimator/low pass filter. The second input of the XOR gate is driven by a square wave from a square wave generator with the same frequency as the guard voltage, but with a substantially 90° phase shift. The output of the decimator/low pass filter is indicative of the capacitance value of the unknown capacitor.

Provided is a flexible, durable capacitive sensor that achieves high flexibility in designing wiring arrangement. A capacitive sensor includes a dielectric layer and a plurality of electrode units placed on both sides of the dielectric layer in the front-back direction. The electrode unit includes an insulating layer having through holes extending therethrough in the front-rear direction, electrode layers placed on one side of the insulating layer in the front-back direction, and jumper wiring layers placed on the other side of the insulating layer in the front-back direction and electrically connected to the electrode layers through the through holes. The insulating layer has an elongation at break of 60% or more, a tension set of less than 5%, and a volume resistivity of 1.0×10.sup.10 Ω.Math.cm or more.

System and method for obtaining and recording information about cargo includes a frame defining a cargo-receivable compartment, a position determining system at least partly on the frame and that allows for determination of position of the frame, an identification system on the frame that obtains information about cargo when present in the compartment, a memory component that receives and records information about position and movement of the frame, and the obtained information about cargo when present in the compartment in association with a unique identification of the frame, and a communications system on the frame to enable communication of information to and from the memory component.

A capacitive sensing device includes an antenna electrode for emitting an alternating electric field in response to an alternating voltage caused in the antenna electrode and a control and evaluation circuit configured to maintain the alternating voltage equal to an alternating reference voltage by injecting a current into the antenna electrode and to measure the current. The control and evaluation circuit includes a microcontroller with a digital output for providing a digital signal and a low-pass filter operatively connected to the digital output for generating the alternating reference voltage by low-pass-filtering the digital signal.

A capacitive occupancy or proximity detector includes a heating circuit, an impedance measurement circuit connected to the heating element and a diagnostic circuit configured for determining integrity of the heater element. The heating circuit includes a heating element, a heating current source and a common mode choke having a first and a second winding, the heating element being connectable to the heating current source via the first and second windings. The diagnostic circuit includes at least one controllable switching element coupled across the second winding circuitry for injecting a DC current into a series connection formed by the first winding, the heating element and a parallel connection of the second winding and said at least one controllable switching element; and at least one detection circuit for detecting a voltage variation across the second winding.

A vehicle seating assembly comprises a seat including a back having an array of at least two electrodes arranged in the back such that a master electrode has an electric field being greater than an electric field of each of the other electrodes within the array to detect a total change in capacitance from the array. A controller is responsive to a change in capacitance calculated from the master electrode being greater than a first threshold and each of the other electrodes in the array being greater than a second threshold and outputs occupant movement data indicative of a first status of the seat to a vehicle control sub-system.

A capacitive detection system for detecting occupancy of a vehicle seat includes a signal generating unit and a signal evaluation unit. The vehicle seat has a seat heater member configured for receiving time-varying output signals of the signal generating unit. The signal evaluation unit is configured to generate an output signal that is indicative of the seat heater member to be defective, if the sensed capacitance of the seat heater member is less than a second predetermined threshold value for the sensed capacitance.

A capacitive sensor for a vehicle seat comprises an antenna electrode and a control and evaluation circuit operatively connected to the antenna electrode. The control and evaluation circuit is configured to operate in a first mode of operation, during which it measures alternating electrical current flowing between the antenna electrode and ground. The capacitive sensor comprises a seat frame connector for connecting the control and evaluation circuit to the seat frame of the vehicle seat. The control and evaluation circuit is configured to operate in a second mode of operation, during which it measures electrical current flowing into the seat frame connector.

The present disclosure relates to a method for detecting a rotation of part of the trunk of an occupant seated on a seat of a vehicle, the method comprising the following steps: triggering a measurement of capacitance values; successively determining, from the measured capacitance values, a first stationary posture of the occupant during a first stationary period, a movement of part of the trunk of the occupant, and a second stationary posture of the occupant during a second stationary period; and calculating, for each capacitive sensor, the variation between the capacitance values measured during the first stationary period and the capacitance values measured during the second stationary period. If the variation calculated for the capacitive sensors is within ranges of capacitance values defined for the capacitive sensors, generating a detection signal.

A system for classifying an occupant located on a seating surface of a vehicle seat. The system includes a movable element and an electrode located in the vehicle seat. A sensing circuit is provided to supply a signal to the conductor. The sensing circuit also includes measurement electronics configured to measure the signal to the conductor and the vibration of the moveable element. A controller is configured to discriminate between different types of objects located on the seating surface based on changes in the signal being supplied to the conductor and the vibration of the moveable element.