The video shows how the Wii mote can pick up three Infra Red Leds (it can pick up 4) .
The X,Y positions of the 3 IR leds can be used to calculate the resulting angle made by them.
This is the meaty part of the code :-
result = ircam.read(); // call the Wii mote camera for some data
angle=atan2(p2y - p1y, p2x - p1x) - atan2(p3y - p1y, p3x - p1x); // simple calculation reveals the angle
This calculates the angle in radians which can be converted to degrees by multiplying by 57.2958
What is show here is a mini version, however the Wii camera is not shy to bigger constructions and stepping way back into the room for bigger ideas.
The idea is to place 4 IR leds onto a robots shoulder ,elbow, wrist and finger and use it for remote motion capture, as it uses the ESP8266 then this data can be relay over WifI to a processing network.