The capacitive switch (and related e-field sensor) has been around for a long time, but in recent years their popularity and applicability have zoomed, as the somewhat complex interface circuit has been put into an highly integrated ICs.
These no-moving-parts switches makes a lot of sense (sorry about the pun) in appliance, automotive, and industrial applications and they allow a new way of thinking about panel layout and appearance, as well. We have published many articles on design considerations as well as new part announcements, among them the following:
1) “Capacitance-to-digital converter eases touch-based switch implementation”
2) “E-field sensor yields nonmechanical touch (or not) switch”
3) “Capacitive touch switches boost automotive interface options”
4) “E-field sensor yields nonmechanical touch (or not) switch”
5) “E-field sensor IC finds new markets”
6) “Integrate a capacitive sensor into your handset, Part II”
Check these out, and bring yourself up-to-date on this technology and its available implementations!