Capacitive sensing is used in interface applications to build non-contact switches (or sensors). When protected by an insulating layer, capacitive sensors provide an elegant design overlay and provide robustness in severe environments.

Very simply, a capacitive sensor is a pair of adjacent plates (electrodes).

When a conductive object is placed in proximity to these electrodes, there is a capacitance between the electrodes and the conductive object. The conductive object is a finger in the following case, though this technique could be applied to any conductive object. Examples include conductive door plates or position sensors.

The most common form of capacitive sensor array is a set of capacitors where one sides of each is grounded. The presence of a conductive object increase the capacitance of the switch to ground, and determining sensor activation is only a matter of measuring change in capacitance.

The PSoC architecture allows designers to incorporate multiple capacitive sensing design elements into an application. Buttons, sliders, touchpads, touch screens and proximity detectors are supported simultaneously with the same device in the same circuit.

The flexibility of PSoC and CapSense allows designers to move across platforms and adapt to design changes quickly. All calibration is completed in software through an easy-to-use, graphical development environment. Application changes do not require migration to other devices because PSoC is highly configurable.

Non-CapSense applications are easily accomplished using PSoC’s digital and analog resources. Use PSoC to scan switches and use the activation status to drive LEDs, control a motor, drive a speaker, etc.

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