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TA1235

Capacitive sensing is emerging as a popular interfacing alternative to switches and knobs in consumer electronics and front panel display applications. This article will discuss many of the sensing methodologies that transform sensor output into useful data that can be used to determine how a user is interacting with a device. The article will discuss strengths, weaknesses, and implementations of established sensing techniques such as E-field Sensing, Charge Transfer, Force-Sensing Resistor (FSR), Relaxation Oscillator, Capacitance-to Digital Conversion (CDC), and Dual-Ramp. It will also introduce two new sensing methodologies, Successive Approximation and Sigma-Delta Modulator. The sensing methods, the process by which capacitance is measured and converted into digital values that can be processed, manipulated and interpreted, are described here.

• 236.88 KB
• 2008/09/23