SELF-CALIBRATING DIELECTRIC PROPERTY-BASED SWITCH

摘要

A self-calibrating touch sensor generally includes a dielectric switch pad in electrical communication with a controller. A forcing function waveform is delivered to the dielectric switch pad. The step response waveform of the dielectric switch pad is then monitored by the controller to detect changes in the dielectric properties of the dielectric switch pad. Upon startup of a system in which the self-calibrating touch sensor is embedded or upon detection of an event indicative of a persistent change in the dielectric environment about the dielectric touch pad, the controller processes the step response waveform to determine the time constant of the circuit comprising the dielectric switch pad. The determined time constant is stored as baseline value by the controller. The controller then monitors the step response waveform for temporary changes from the stored value, indicative of a key press event.