A method of proximity sensing which comprises emitting light from an emitter and detecting reflected light, applying an offset to the detected reflected light to provide an output signal indicative of proximity, determining an average signal of the output signal; determining whether drift has occurred by comparing the output signal to a first threshold and comparing the average signal to a different threshold, and adjusting the offset if drift is identified.

A capacitive sensor with a plurality of sense inputs connectable to capacitive sense electrodes and a common reference input, each sense input and the reference input can be put in a measure state, in a ground state, or in a shield state. The sensor can be equipped with external reference capacitors between each of the sense input and the common reference terminal. The reference capacitor can be read individually by selectively pulling one of the input terminals to ground and driving the other to be equipotential with the reference input.

A proximity switch is disclosed. In an embodiment, the proximity switch has a defined detection range and includes an oscillator, an oscillator amplifier, a temperature sensor, a microprocessor and a storage medium. The oscillator generates an alternating magnetic field and changes its oscillation state as a result of a target entering the detection range. The oscillator amplifier is configured to be controllable in an open-loop and closed-loop manner and has at least one amplifier stage. In this embodiment, the at least one amplifier stage has a controllable temperature compensation circuit which is configured to influence the oscillation behaviour of the oscillator based on compensation values received as control data from the microprocessor and/or from the storage medium, depending on a temperature detected by the temperature sensor. The disclosed embodiments also encompass a method for operating a proximity switch with temperature compensation.

The present application relates to a method of operating a capacitance sensing device comprises: calculating a difference of a raw data compared to one of the raw data received in a previous data frame; and performing a comparison calculation based on the raw data and a stored baseline value to determine whether a proximity event has occurred. Under the proximity event, selects one of several baseline value update procedures based on the magnitude of the difference. Thus, the present application effectively avoids the problem of failure to update the baseline value when the object is close to the capacitance sensing device for a long period of time, which may lead to misjudgment of the capacitance sensing device.

The present invention relates to a capacitive sensor device comprising a capacitance-measuring circuit, a main sense input and a reference sense input, wherein the capacitive sensor device is configured to measure, using the capacitance-measuring circuit, a current main value of capacitance seen by the main sense input and a current reference value of capacitance seen by the reference sense input, wherein the capacitive sensor device is configured to at least temporarily store at least one previously measured reference value, and wherein the capacitive sensor device is configured to use 1) the current main value, 2) the current reference value and the at least one previously measured reference value, and 3) at least one current correction coefficient, with the capacitive sensor device being configured to adaptively determine the at least one current correction coefficient based on at least the current reference value and the at least one previously measured reference value, for determining a corrected current main value of capacitance. The present invention further relates to a portable electronic device comprising the capacitive sensor device.

A portable device including a capacitive proximity sensor can suppress a drift superimposed to the capacitive proximity signal and the corresponding method. A processor generates a baseline value by integrating a series of values that are derived from the slope of the proximity signal, when the slope is within stated limits, or a fixed value outside of the stated limits.

A mobile device has a proximity sensor. A compensation value of the proximity sensor is determined. The compensation value is compared to a reference compensation value to determine validity of the compensation value. A capacitance of the proximity sensor is measured. A value of the capacitance of the proximity sensor is adjusted based on the compensation value. A coefficient defining a relationship between a capacitance of the proximity sensor and a temperature of the mobile device is calculated. A temperature sensor is coupled to the proximity sensor. The temperature of the mobile device is measured. A value of the capacitance of the proximity sensor is adjusted based on the coefficient and the temperature of the mobile device. The adjusted capacitance value is compared to a threshold capacitance value to determine proximity of an object to the mobile device. A radio frequency signal is adjusted by detecting proximity.

A sensor device has: a sensor unit that outputs a sinusoidal detection signal having an amplitude matching a physical quantity to be detected; a reference signal creator that creates a first sinusoidal reference signal having the same frequency and phase as the detection signal; and a demodulator that multiplies the detection signal by the first reference signal and creates, as a first demodulation signal matching the physical quantity, a signal matching a direct-current component included in a signal resulting from the multiplication. The reference signal creator creates a sinusoidal second reference signal having the same frequency as the detection signal but being out of phase with the detection signal. The demodulator multiplies the detection signal by the second reference signal and creates, as a second demodulation signal matching a noise component superimposed on the detection signal, a signal matching a direct-current component included in a signal resulting from the multiplication.

A method for operating a capacitive touch-sensitive switch having a capacitive sensor element and a sensor circuit includes initially setting a scanning frequency of the capacitive touch-sensitive switch with a good signal-to-noise ratio and then operating the capacitive touch-sensitive switch at a scanning frequency which has been set to detect switch actuation. The process of setting the scanning frequency includes operating the touch-sensitive switch using a first measurement method and at a selected scanning frequency, detecting the measurement signals from the sensor circuit and checking whether the detected measurement signals contain or could contain a critical alias effect. If no critical alias effect and no possibility of a critical alias effect are detected during the check, the scanning frequency can be set as the selection frequency for detection operation of the touch-sensitive switch. A capacitive touch-sensitive switch is also provided.

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.