The technology called uTouch that works by measuring the electromagnetic interference caused by your hand when it moves near or touches an LCD monitor. This will sound a little bit crazy. The electricity running through the wires in your house has a unique electromagnetic signature. There is the carrier wave that provided by the power company and your nearby substation. Just switch along the way modulates the EM signature until it is quite unique.
How to convert LCD monitor to touch screen?
Every device that is plugged into a wall outlet also changes your EM signature. Your TV will not just suck power from your house and it is a two way street with the electronic components in the TV that producing interference and change your houses EM signature.
Now you can plug an EMI sensor into any wall socket and you can read your EM signature. It might sound a bit unbelievable that a single finger moving towards an LCD monitor can be detected by a sensor at the other end of the house. Every LCD monitor has a massive matrix of wires that are connected to every single pixel. These pixels are updated row by row at a speed that is dictated by the monitor row rate. The row rate is generated by a row driver.
The uTouch technology will probably never be used on a standard desktop monitor or laptop but it will be useful in the living room, commercial spaces where large expensive displays that will be turned into touch screens. Throw light wave into the equation and it is easy to imagine dumb and non-interactive spaces suddenly becoming richly interactive. The ultimate goal is to find cheap and easy ways of making everything around are interactive.