Capacitive sensing libraries for the Arduino and just about every other ... be made into a smallish keyboard, and the radial touch sensor will emulate the ‘wheel’ interface on an iPod.

The sensor shown here is essentially two plates mounted side-by-side, attached to an Arduino Nano using the ... a spring elegantly used as a hidden touch sensor that works through an enclosure ...

A DIY The Wrench maker has built a smart desk dustbin with an automatic iris-style lid, adding both functionality and a ...