Capacitive sensors can be used to detect or take measurements of anything containing conductive materials that can be polarised by an electric field (provided that the resulting dielectric is different from that of the surrounding air). They are commonly used as proximity sensors but also find a host of applications in other kinds of sensor for measuring pressure, location, displacement, acceleration, force, fluid levels or humidity. By extension, they are also used as touch buttons or touch screens in devices such as smartphones, tablet computers and audio players.
