Build your own touch screen using light triangulation and CIS sensor!
This tutorial is about helping people to build their own touch screen solution based on any flat screen TV. It uses light triangulation technology to read the coordinates. This method is quite cheap ( the priciest part is the TV), with a good quality image and you can make the table almost as small and as thin as your TV is.
Of course, nothing is perfect and with this solution it's probably not possible to build a 100% multi-touch screen and it's hard to cover the entire screen area. But depending on the way you make it you can have some interesting results. Plus, I am sure there are a lot of possibilities I haven't thought about to improve this. ;-)
All the information are here : https://hackaday.io/project/27155-touch-screen-coffee-table-diy-with-low-cost-sensor
The second solution is to build a Magic Frame with only IR LED and sensors. This project is turning on/off a light throw Z-wave depending on the movement of the hand inside the frame. All the informations are here : https://makershare.com/projects/magic-frame-everything-touch-area
