Oh, so (to use an example) the Wii can detect your position in space because of something else and not accelerometer, right?
The wii detects the position in space because of the sensor bar, and wiimote camera.
The wiimote has 3 different detector :
: displacement speed of the wiimote
: orientation, rotation, tilting (2 axis at a time, due to gravity, left/right, upward/backward, but cant detect your if your body is moving to the left or the right, it's the job of the visual position
the visual position
also act as rotation verification for 2 axis :
- on the axis from the TV and you, if you point to the TV, and tilt the wiimote from left to right without moving your arm away from your chest, the wii check if it's the same movement that the gyroscope detects (sometime, your hand cursor is upside down for a few second, because the sensor see the rotation but can't detect the side until to gyro tells it to the wii).
- on the Z axis (moving your entire body to the left or right), the sensor "see" the wiimote moving from one point to another, until it's out of screen.
is another gyroscope/accelerometer, which detect the same thing as the one in the wiimote, but as they are 10cm apart from each other, their inclination and moving speed is different. Their differences give even more indications and adds a precision on what movement you are doing (even if the sensor can't see you).
It then reproduce a sword movement correctly.
But it needs a very good calibration of both detectors, that's why there's a calibration function in Wiimote+ games.
For a little more specifications on the gyroscope and accelerometer :
Actually the Accelerometer can do both jobs, but it's not always accurate.
The accelerometer acts as a gravity detector to check which side the wiimote is facing.
Moving the wiimote creates a force on the opposite direction.