CNN reports on some of the motion-sensitive parts that make the PS3 and Wii controllers possible. These special sensors are based on tiny springs that make circuits when jolted, while sensitive meters measure the flow of electricity through the connection.
How tiny are the parts? The silicon pieces that flex against the springs weigh about a millionth of a gram. And they only move slightly when the controller shakes -- the distance of 10 to 100 hydrogen atoms -- but their position can still be measured.
The sensors have existed for years but were only recently cheap enough for games, at less than $1 per axis, making motion tracking the new arms race in game control. Will the 360 -- or next Xbox -- have motion control?