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Sensor- and Recognition-Based Input for Interaction
Published in Julie A. Jacko, The Human–Computer Interaction Handbook, 2012
Capacitive sensing is based on the property that nearly any object is capable of storing electric charge, and that charge will flow between two objects when touching or in close proximity. A zero-force touch sensor can be implemented with a charge transfer technique, whereby the capacitance of an electrode is estimated by measuring the time taken for an electrode to discharge a small applied charge (Hinckley and Sinclair 1999). This time drops dramatically when the user places a finger on the electrode, since the user’s body takes on much of the charge. Other capacitive sensing techniques can sense an object before it touches the electrode, making them suitable as proximity sensors for a wide variety of interactive applications (Baxter 1996; Smith 1999; Vranish, McConnell, and Mahalingam 1991). Multiple electrodes can be used to implement position sensitive sliders, such as the wheel on the Apple iPod.
Elements of the Technology
Published in Thomas B. Sheridan, Telepresence: Actual and Virtual, 2023
Robotic touch sensing can be based on many principles: capacitors, piezoelectric material, strain gauges, color changes, optical intensity, etc. There are two types of capacitive sensing systems: (1) mutual capacitance, where the object (finger, conductive stylus) alters the mutual coupling between row and column electrodes, which are scanned sequentially, and (2) self- or absolute capacitance, where the object (such as a finger) loads the sensor or increases the parasitic capacitance to ground (Figure 2.12). Currently, there are electrically conductive polymers that are useful in touch sensors.
Coplanar capacitive sensors and their applications in non-destructive evaluation: a review
Published in Nondestructive Testing and Evaluation, 2023
T. Zhu, K. Wen, Z. Zhang, X. Yuan, W. Li, X. Yin
The capacitive sensing technique is based on the principles of electric field theory. Generally, in the parallel-plate capacitor, when a potential is applied between the two adjacent electrodes or plates separated by a gap containing a dielectric, an amount of charge builds up on either plates and an electric field is produced as shown in Figure 2. The ability of this capacitor to store a certain amount of charge on its plates is referred to as its capacitance, , expressed as in Equation (1) and Equation (2).
Demulsification of crude oil emulsion by capacitative sensor system measurement: introduction to apparatus and methodology
Published in Journal of Dispersion Science and Technology, 2019
Vaibhav Kedar, Sunil S. Bhagwat
Capacitive sensor technologies and their use as sensors in various industrial applications are well known. Capacitive sensing is becoming a popular technology to replace optical detection methods and mechanical designs for applications like proximity/gesture detection, material analysis, and liquid level sensing.[15,16] The main advantages that capacitive sensing has over other detection approaches are that it can sense different kinds of materials (plastic, metal, liquid).[17]