Projectors have been directly connected to PC for a long time, but in more recent years the idea of using projectors as the basis of some user input has been gaining a lot of steam. In this tradition HP is releasing a new PC called Sprout which eschews the traditional keyboard and mouse for a projector and a 20-point touch-enabled mat.
Sprout takes advantage of a High-Resolution Camera with up to 14.6 megapixel resolution and the Intel® RealSense™ 3D Camera for instant capture of 2D and 3D objects, along with a Adonit Jot Pro stylus to write and draw with precision and comfort.
I love experimenting with HMI and UX, however, the novelty of the experience never trumps the reliability and usability for long (I am looking at you Kinect). Here is the thing, if my keyboard worked 97% of the time it would be disastrous and in fact I would assume that I simply needed a new keyboard. Inputs either have to deliberately appeal to the most simple gestures and commands or be first class inputs (like the keyboard and mouse), this is clearly being positioned as a first class input device. At $1900 (decent price IMHO) I hope they have really nailed it!