Using a computer mouse provides two levels of depth when interacting with content on a screen. One can just hover or can click. Hover allows receiving short descriptions, while click selects or performs an action. PreCursor provides this missing sense of interaction to touchscreens.

Pranav Mistry from MIT is working on a project called PreCursor that can turn any regular computer monitor into a touch screen. 

See PreCursor in action:

 How PreCursor Works ?

PreCursor’ is an invisible layer that hovers in front of the screen and enables novel interaction that reaches beyond the current touchscreens. The touchscreen created by PreCursor is in a way more versatile. In addition to the regular tap /click gesture, it can recognize the hover action, something which require a mouse and is possible to do with existing touch screens.

Also see: ZeroTouch – A Multi-Touch Screen to Write in Thin Air

Precursor can also be used  with mobile devices and objects in the real world, or can be the launching pad for creating a 3D space for interaction.