Capacitive sensing has replaced mechanical buttons in a wide range of consumer appliances, including washing machines, music players, and mobile phones, to name a few. This has been possible largely because capacitive sensors are durable, more reliable, and provide better aesthetics through their simple yet elegant user interface that supports multiple functionalities at literally the tip of a finger. The quality of a capacitive sensing implementation, however, depends upon its response time and power consumption. Highly responsive systems give a real-time feel while reducing power consumption improves operating life in the case of battery-based devices. In this article, we discuss some standard capacitive sensing elements and applications with a focus on balancing power consumption and response time for embedded engineers developing capacitive sensing interfaces.
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