A transform is used to transform raw sensor data from the time domain to the frequency or sequency domain. The transformed data falls into several signal bins. The transformed data in at least one of the signal bins is analyzed to determine whether a touch event or release event has occurred.

A method for detecting contact of a capacitive sensor includes transferring charge quantities in multiple successive cycles from the capacitive sensor to an integration capacitor having a known capacitance value. A voltage of the integration capacitor is measured. The measured voltage is processed to generate a sensor amplitude that is indicative of a capacitance value of the capacitive sensor. Contact of the capacitive sensor is detected based on a temporal behavior of the sensor amplitude. For instance, contact of the capacitive sensor is detected based on the rate of change of the sensor amplitude.

A touch sensitive capacitive keypad system (100) is provided with an analog-to-digital converter, a keypad sensing electrode (114) coupled to measure capacitance voltages using a configurable electrode scan rate, and a controller (120) configured to provide scan-rate independent capacitance voltage measurements from the keypad sensing electrode to the analog-to-digital converter when there is a change in the configurable electrode scan rate by repetitively sampling a capacitance voltage measurements (e.g., 524a-f) from the keypad sensing electrode over a plurality of sequential electrode scan cycles and then discarding a predetermined number of the capacitance voltage measurements (e.g., 524a-b) to generate the scan-rate independent capacitance voltage measurements (e.g., 524c-f) that are provided to the analog-to-digital converter.

A person or object is infused with a signal. The infused signal has a phase relationship with the signals that are transmitted from and used by a touch sensor, controller or wearable. The phase relationship of the infused signal is used in order to increase the ability of receivers at or on the touch sensor, controller or wearable to measure and determine touch events, such as hover.

A capacitance detection device detecting a capacitance between a detection electrode and a detection target close to the detection electrode has: a first voltage output circuit that outputs a first alternating current voltage to be supplied to a shield electrode placed close to the detection electrode; a second voltage output circuit that outputs a second alternating current voltage with substantially the same frequency as the first alternating current voltage; and an operational amplifier that amplifies the difference in voltage between an inverting input terminal connected to the detection electrode and a non-inverting input terminal to which the second alternating current voltage is applied, and outputs the amplified difference in voltage. With the detection target close to the detection electrode, the second voltage output circuit outputs the second alternating current voltage adjusted so that an output voltage from the operational amplifier has a smaller amplitude than the first alternating current voltage.

A multipoint contact detection device includes at least two capacitive or inductive sensitive structures associated with respective primary detection zones of a surface that a person is likely to contact. The sensitive structures are positioned with a separation that is small enough between them to define at least one intermediate detection zone that the person is likely to contact while exerting a capacitive or inductive disturbance on the adjacent sensitive structures. The device also includes a processing circuit configured to detect, for each sensitive structure, a disturbance induced by the person coming into proximity or into contact and locating the region or regions of the surface with which the person comes into contact relative to the primary detection zones and the one or more intermediate detection zones.

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. The method includes, for each predefined signal frequency: determining statistical quantities and signal parameters regarding a number of determined momentary values of an unknown complex impedance; eliminating portions up to a predefined hand touch movement lower limit frequency and from a predefined high-frequency limit down to a predefined hand touch movement upper limit frequency; excluding statistical outliers from determined momentary values; and using an eliminated frequency portion for calculating a momentary reference value for the unknown complex impedance.

A method of capacitive sensing may include transmitting a first sensing signal along a first transmitter electrode among various transmitter electrodes of an input device. The method may further include obtaining, using various receiver electrodes in the input device, a first resulting signal in response to the first sensing signal being transmitted along the first transmitter electrode. The method may further include obtaining a second resulting signal from a second transmitter electrode among the transmitter electrodes. The method may further include determining, using the second resulting signal, interference along the second transmitter electrode. The method may further include adjusting, using the interference along the second transmitter electrode, the first resulting signal to produce an adjusted resulting signal. The method may further include determining, using the adjusted resulting signal, positional information regarding a location of an input object in a sensing region of the input device.

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.

The present disclosure provides a touch detection circuit, its driving method and a display device. The touch detection circuit includes a touch sensing electrode, a switch control unit, a touch detection unit, a first control signal terminal, a second control signal terminal, a third control signal terminal, a fourth control signal terminal, and a signal output terminal. At a charging stage subsequent to an initialization stage, a touch capacitance is generated at a position corresponding to the touch sensing electrode in the case that the touch sensing electrode is being touched, and the touch sensing electrode is charged through the switch control unit under the control of the first control signal terminal. As a result, it is able to detect charges stored on the touch sensing electrode by the touch detection unit at a detection stage, thereby to determine whether or not the touch sensing electrode is being touched in accordance with a detection signal from the signal output terminal.