Touch sensitive switches have very low activation forces. As low as it
is reasonably possible to get, short of gesture recognition, perhaps.|
While not practical as keyswitches on an ordinary keyboard, they do have applications.
Touch sensitive light switches are widely available:
This particular switch needs a huge 47mm pattress box, and has extremely irritating dimmer functionality - which prevents it from working with compact fluorescent bulbs - but the switch fuctionality is of good quality.
This type of switch uses a charged surface and capacitance to detect contact. The degree of touch sensitivity in response to finger touches is very good.
It would be nice if this switch technology was available for computer input devices. It would be useful for infrequently-pressed switches.
However, there seem to be some issues:
LinksTouch Mouse - Mouse operated by a touch switch