How to use "Tobii Eye Tracker 4C" to communicate with a child who can not talk and move (SMA, CP, BAS)

How to use "Tobii Eye Tracker 4C" to communicate with a child who can not talk and move (SMA, CP, BAS)  
 
The methodology is based on tracking the direction of view, which is carried out by the device "Tobii Eye Tracker 4C". A table with several pictures is displayed on the computer screen. If you hold your eyes on a separate picture, then the corresponding phrase will be sounded, for example, "drink", "turn on your side", "watch cartoons".
 
When a child learns letters, it will be possible to use more complex methods, such as typing the text with the eyes (see Habr.com/post/208108 )
 
 
What will be required (in a nutshell)?
 
1) computer
 
2) light trekker - tracking device
 
3) free software ...
+ 0 -