Capacitive sensing

About: Capacitive sensing is a research topic. Over the lifetime, 31727 publications have been published within this topic receiving 365496 citations. The topic is also known as: capacitance sensing.

Wireless and powerless sensor and interrogator

Abstract: Arrangement and method for monitoring a tire mounted to the vehicle in which a thermal radiation detecting device detects the temperature of the tire at different circumferential locations along the circumference of the tire. The detected temperatures of the tire are analyzed to determine, for example, whether a difference in thermal radiation is present between the circumferential locations of the tire, and if so, an action is effected in response to the analysis. The thermal radiation detecting devices are preferably supplied with power wirelessly, e.g., through an inductive system, a capacitive system or a radio frequency energy transfer system.

Two-dimensional position sensor

Abstract: A capacitive position sensor for determining the position of an object along first and second directions is described. The sensor comprises a substrate having an arrangement of electrodes mounted on a single surface thereof. The electrodes are arranged so as to define an array of sensing cells arranged in columns and rows to form a sensing area. Each of the sensing cell including a column sensing electrode and a row sensing electrode with the column sensing electrodes of sensing cells in the same column being electrically coupled together and the row sensing electrodes of sensing cells in the same row also being electrically coupled together. Row sensing electrodes of sensing cells at opposing ends of at least one of the rows are connected together by an electrical connection made outside of the sensing area so that there is no requirement for electrical connections to cross within the sensing area, thus providing a capacitive position sensor having a sensing area with electrodes on only one side of a substrate.

Capacitive sensor and array

Abstract: Proximity of a body, which may be a user's finger, to an electrode pair (100, 104) is sensed by a charge transfer capacitive measurement approach. The electrode pair (100, 104) thus act as a key (10) that can be arrayed with other electrode pairs to form a keypad, keyboard, linear slider control, or liquid level sensor. In one embodiment of the invention, each key is associated with an alternating voltage source (101) and a pair of electrodes (100, 104) mounted on or within a solid dielectric substrate (103) or panel so as to be separated from each other by a gap. The voltage source (101) is connected to a driven electrode (100), a sampling charge detector (402) is connected to a second, receiving, electrode (104), and the output of the charge detector is, in turn, fed into an amplifier (403) and a charge measurement means (407). Disturbances in coupling between the two electrodes (100, 104) are detected through the solid substrate or panel material (103) when a substance or object approaches or contacts the panel. The receiving electrode (104) is a low-impedance node during the sampling phase of the process, which aids in keeping the sensor from being affected by wiring length or extraneous objects near an output lead.

Super-stretchable, Transparent Carbon Nanotube-Based Capacitive Strain Sensors for Human Motion Detection

Abstract: Realization of advanced bio-interactive electronic devices requires mechanically compliant sensors with the ability to detect extremely large strain. Here, we design a new multifunctional carbon nanotube (CNT) based capacitive strain sensors which can detect strains up to 300% with excellent durability even after thousands of cycles. The CNT-based strain gauge devices exhibit deterministic and linear capacitive response throughout the whole strain range with a gauge factor very close to the predicted value (strictly 1), representing the highest sensitivity value. The strain tests reveal the presented strain gauge with excellent dynamic sensing ability without overshoot or relaxation, and ultrafast response at sub-second scale. Coupling these superior sensing capabilities to the high transparency, physical robustness and flexibility, we believe the designed stretchable multifunctional CNT-based strain gauge may have various potential applications in human friendly and wearable smart electronics, subsequently demonstrated by our prototypical data glove and respiration monitor.

Ultrahigh humidity sensitivity of graphene oxide

Abstract: Humidity sensors have been extensively used in various fields, and numerous problems are encountered when using humidity sensors, including low sensitivity, long response and recovery times, and narrow humidity detection ranges. Using graphene oxide (G-O) films as humidity sensing materials, we fabricate here a microscale capacitive humidity sensor. Compared with conventional capacitive humidity sensors, the G-O based humidity sensor has a sensitivity of up to 37800% which is more than 10 times higher than that of the best one among conventional sensors at 15%–95% relative humidity. Moreover, our humidity sensor shows a fast response time (less than 1/4 of that of the conventional one) and recovery time (less than 1/2 of that of the conventional one). Therefore, G-O appears to be an ideal material for constructing humidity sensors with ultrahigh sensitivity for widespread applications.