Non-contact position and motion sensing is improved for oscillator frequency based sensors in response to adding a two phase calibration along with bootstrapping circuit. Calibration is performed across the multiple sensor channels, so that: (1) maximum sensor channel loading is determined, and (2) the amount of capacitive load required for each other channel to match this same maximum load is stored for application to that channel during non-contact sensing. Capacitive coupling between channels is nullified by a bootstrapping process, in which time-domain voltage on the active channel is replicated on the non-active channels during non-contact sensing, thus creating equal potentials across inter-channel couplings that effectively eliminate inter-channel capacitive loading.

A sensing device includes a comparator, a first and a second variable capacitor units. The first and second variable capacitor units charge a first and a second comparator inputs, respectively, according to a first and a second driving signals, such that the first and second comparator inputs have a first and a second voltages, respectively, in which a voltage level of the first driving signal is higher than a voltage level of the second driving signal. The comparator is configured to compare the first voltage and the second voltage to generate a comparator output signal. The first variable capacitor unit is adjusted according to the comparator output signal to perform potential compensation for the first comparator input, or the second variable capacitor unit is adjusted according to the comparator output signal to perform potential compensation for the second comparator input.

The invention relates to a capacitive sensor system, in particular for detecting the approach of objects and in particular also for gesture recognition. The problem of the present invention is to provide a capacitively operating sensor system, which can be implemented with low component complexity and thus low costs and space requirements and is also characterized by low power consumption, so as to operate with batteries having a low charge capacity and/or a long operating time. Said problem is solved according to the invention by a circuit configuration for generating an output signal correlating with an approximation process based on changes in the dielectric properties of the surroundings of a sensor electrode, having a sensor electrode which is adjacent to an observation area in at least some sections, a microcontroller circuit (C) for output of an alternating voltage, a voltage divider circuit for achieving an adjustment of the level of the alternating voltage output by the microcontroller (C), and a field effect transistor (FET) in the function of an impedance converter, wherein the field effect transistor is incorporated into the circuit configuration in such a way that the voltage output by the voltage divider circuit is present at the gate input thereof and at the same time at the sensor electrode (ES).

An occupancy monitoring device, such as for a bed or chair, including a capacitor having a first electrode adapted for attachment along the side of a bed or mattress or a chair, a second electrode adapted for positioning remotely from the first electrode and a defector tor detecting dielectric shift induced in the capacitor by movement of an occupant on the bed, mattress or chair.

A sensing device includes a comparator, a first and a second variable capacitor unit. A first comparator input of the comparator is electrically coupled to a touch pad. The first variable capacitor unit is configured to charge the first comparator input such that the first comparator input has a first potential. The second variable capacitor unit is configured to charge a second comparator input of the comparator such that the second comparator input has a second potential. The comparator is configured for comparing the first potential and the second potential to generate a comparator output signal. In a condition of the touch pad being operated, the first variable capacitor unit is adjusted according to the comparator output signal to perform potential compensation for the first comparator input, or the second variable capacitor unit is adjusted according to the comparator output signal to perform potential compensation for the second comparator input.

An apparatus and method wherein the apparatus comprises;a sensor arrangement comprising a plurality of sensor cells wherein a sensor cell comprises a transistor and a sensor coupled to the transistor;first selection circuitry configured to sequence a subset of sensor cells to which a gate input signal is provided, wherein the gate input signal is provided to the gate of the transistors within the sensor cells; second selection circuitry configured to sequence a subset of sensor cells from which an output signal is received;sensing signal circuitry configured to provide a sensing signal, wherein the sensors are provided between the sensing signal circuitry and the second selection circuitry such that the output signal provides an indication of the impedance of the sensors.

Disclosed are devices and methods for detecting activation of an electronic device, including a biomedical and biometric device. The electronic device can operate in a low-power mode until it is determined that the electronic device is in close proximity to or in contact with a body, and activated. The electronic device can include a first sensor including a first capacitance sensor, a second sensor, and a controller coupled to the first sensor and the second sensor. The controller can receive a first signal from the first sensor and determine that the electronic device is in close proximity to or in contact with a body based on the first signal, and receive a second signal from the second sensor and determine that the electronic device is activated based on one or both of the first signal and the second signal. The electronic device can transition from the low-power mode to an active mode in response to determining that the electronic device is activated.

A method and apparatus include a plurality of sensor elements arranged within an integrated circuit package and a controller arranged within the integrated circuit package and coupled to the plurality of sensor elements. The controller is configured to apply a transmit signal to a first sensor element of the plurality of sensor elements and receive a receive signal from a second sensor element of the plurality of sensor elements. The receive signal represents a mutual capacitance of the first sensor element and the second sensor element.

An apparatus includes a keyboard and circuitry. The keyboard includes at least an interface line and a key. The key is configured to connect the interface line to first and second different capacitances when positioned in first and second positions, respectively. The circuitry is connected to the interface line and is configured to detect whether the key is in the first position or in the second position, by sensing electrical current flowing on the interface line in response to a stimulation waveform.

A method and device for measuring a variation of a capacitance, the device includes: a capacitance having a voltage across its terminals; a charging element and a discharging element; a comparison element; control elements activating the charging element or the discharging element as a function of the value of the voltage across the terminals of the capacitance and of which an output voltage has a high value during the charging and a low value during the discharging; a counter measuring a time representative of a predetermined number of charging and discharging cycles of the capacitance; and an additional capacitance electrically connected to the output voltage and to the capacitance, able to be charged and discharged simultaneously with the charging and discharging of the capacitance.