I watched the video and i didnt know what was happening
Then i read this and still didnt really know what it was.
Then it clicked when i read "I bet they had to put a seperate red light in each room tho...."
Thats when i worked out its using a building

Then i read this and still didnt really know what it was.
Then it clicked when i read "I bet they had to put a seperate red light in each room tho...."
Thats when i worked out its using a building


At least it might be possible with mains networking technology of some sort.