Methods and apparatus to determine a position of a rotatable shaft of a motor are disclosed. An example apparatus to determine a position of a rotatable shaft of a motor includes a sensor printed circuit board (PCB) structured to be mounted to a motor, the sensor PCB including a plurality of capacitive sensors, the plurality of capacitive sensors having respective ones of a plurality of capacitances that independently change as a conductor moves relative to the sensor PCB in conjunction with a rotatable shaft of the motor during an operation of the motor, and a controller electrically coupled to the sensor PCB, the controller configured to determine a position of the rotatable shaft based on the plurality of capacitances.

Embodiments of the present disclosure provide a method for updating a capacitance reference, which includes: determining, based on an n-th frame of raw capacitance data and an (n?M)-th frame of raw capacitance data outputted from the capacitance detection apparatus, a feature value corresponding to the n-th frame of raw capacitance data; computing a difference value between the n-th frame of raw capacitance data and a reference value corresponding to an (n?1)-th frame of raw capacitance data outputted from the capacitance detection apparatus, to obtain a capacitance variation; and determining, when the feature value corresponding to the n-th frame of raw capacitance data is less than a first threshold Thr.sub.1, and the capacitance variation is less than a proximity threshold Thr.sub.on, the n-th frame of raw capacitance data or the (n?1)-th frame of raw capacitance data as a reference value corresponding to the n-th frame of raw capacitance data.

Techniques for manipulating objects and for determining the position of the objects in parallel dipole line (PDL) trap systems are provided. In one aspect, a PDL trap is provided. The PDL trap includes: a pair of dipole line magnets connected to a potential, wherein the pair of dipole line magnets includes magnets having magnetizations perpendicular to long axes of the magnets; a diamagnetic rod levitating above the pair of dipole line magnets; and at least one electrode above the pair of dipole line magnets, adjacent to the diamagnetic rod. The system produces a hybrid one-dimensional electromagnetic potential which is tunable by voltage. Techniques for operating the PDL trap to manipulate the diamagnetic rod and to detect a position of the diamagnetic rod in the PDL trap are also provided.

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 robot includes a body and a bumper. The body is movable relative to a surface and includes a first portion of a sensor. The bumper is mounted on the body and movable relative to the body and includes a backing and a second portion of the sensor. The backing is movable relative to the body in response to a force applied to the bumper. The second portion of the sensor is attached to the backing and movable with the backing relative to the first portion of the sensor in response to a force applied to the bumper. The sensor is configured to output an electrical signal in response to a movement of the backing. The electrical signal is proportional to an amount of displacement of the second portion relative to the first portion.

A capacitance type rotation angle detection stage light includes a pivoting member and a supporting member for supporting the pivoting member. A reflecting grating is attached on the pivoting member, and the reflecting grating rotates along with the pivoting member. A signal grating is attached on the supporting member. The signal grating and the reflecting grating are arranged oppositely. The signal grating comprises capacitance emitting pieces, a capacitance receiving piece and shielding pieces. The reflecting grating comprises capacitance reflecting pieces that reflect signals sent from the capacitance emitting pieces to the capacitance receiving piece. Periodic excitation signals applied to the capacitance emitting pieces finally form a composite signal on the capacitance receiving piece through coupling of two pairs of capacitors that the capacitance emitting pieces and the capacitance reflecting pieces, and the capacitance reflecting pieces and the capacitance receiving piece.

A method for measuring a capacitance value of a capacitive sensor uses an integration process involving charge quantities being transferred in successive integration cycles from the capacitive sensor to an integration capacitor. The method includes performing the integration process until the number of integration cycles carried out has reached a number N of integration cycles to be carried out, wherein a starting value N.sub.Start is set to N and an end value N.sub.End is determined. An A/D converter measures a voltage value U.sub.CI(N) at the integration capacitor and the voltage value is added to a voltage sum value U.sub.Total. The number N is increased by a value n, where n is at least one and is less than N.sub.Diff=N.sub.End?N.sub.Start. The steps are repeated until the number N exceeds the end value N.sub.End. The ending voltage sum value is indicative of the capacitance value of the capacitive sensor.

A linear actuator includes a casing that contains a moveable shaft moved by a motor in response to a drive signal and coupled to an encoder that determines an actual instantaneous position of the shaft and forms part of a control loop that adjusts the drive signal so as to ensure accurate positioning of the shaft. A temperature sensor mounted on the shaft produces a temperature signal indicative of instantaneously measured temperature, and a temperature compensator responsive to the measured temperature for generating a negative or positive offset for correcting the drive signal so as to move the shaft to a positon that is corrected for instantaneous expansion or contraction of the shaft owing to departures of the shaft's actual temperature from a known baseline temperature.

A capacitance detection device includes at least one detection electrode, a shield electrode disposed in close vicinity of the detection electrode, an AC signal source that supplies an AC signal to the shield electrode, a detection circuit that detects capacitance between a physical object in close vicinity of the detection electrode and the detection electrode on the basis of a detection signal output from the detection electrode and the AC signal output from the AC signal source, and a phase adjustment circuit provided between the AC signal source and the shield electrode. The phase adjustment circuit advances the phase of the AC signal output from the AC signal source.

A sensor system for counting elements of a flow of harvested material. The sensor system comprises an oscillating circuit and a measuring device, wherein the oscillating circuit comprises at least one capacitive component with a capacitance and an inductive component with an inductance. The oscillating circuit has a resonance frequency which depends on the capacitance and the inductance. Further, the capacitive component is positioned in the region of the flow of harvested material, so that the capacitance is influenced by individual elements of the flow of harvested material. The measuring device is configured to determine the resonance frequency of the oscillating circuit. In this way, the sensor system is configured to deduce at least one property of the particular element of the flow of harvested material from the resonance frequency of the oscillating circuit.