Initially discounted by game-industry watchers as graphically underpowered compared with the Sony PlayStation 3 and ­Microsoft Xbox 360, the Nintendo Wii has wiped the sales floor with its competitors. In February 2007, 335,000 Wiis were sold in the U.S., versus 228,000 Xbox 360s and 127,000 PS3s. Behind the Wii's success is its unique controller: simple and wireless, it responds to your movements in a natural manner, turning into a baseball bat, a sword, or a hand, as necessary. It is, in a word, fun.

MEMS Sensor 1 (Wii Remote)
The key to the Wii's main controller is its three-axis microelectromechanical-system (MEMS) accelerome­ters, which measure movement in three dimensions. Two-dimensional MEMS sensors have been around for a while, but adding the third axis presented challenges. "You have moving parts that you have to protect from the environment," says Christophe Lemaire, a marketing manager at Analog Devices, which makes the sensor used in the Wii Remote. Most MEMS sensors come in hermetic packages made from ceramics or metals. But this increases the devices' size and cost--a problem that the additional sensory dimension was only going to aggravate. "What we do," says Lemaire, "is put a cap over the sensor elements at the wafer level." That creates a hermetic cavity and enables the use of a cheap, small, lightweight case.

Bluetooth
The Wii Remote uses a Broadcom Bluetooth chip to wirelessly send a constant stream of position, acceleration, and button-state data to the Wii console. The chip also contains a microprocessor and RAM/ROM memory for managing the Bluetooth interface and converting voltage data from the accelerometers into digitized data.