Biomedical Engineering Reference
In-Depth Information
Fig. 7.16
GAITER. Courtesy of Jim Templeman, U.S. Naval Research Laboratory
We have plotted several other common input devices. The Polhemus Fastrak
tracker is a widely used magnetic tracker which reports the six-DoF position and
orientation of a device in a coordinate system centered on a transmission device.
A Wii Remote with MotionPlus is a relatively complex device with four sets of
sensors. The first is that the device has 11 buttons on it that (plus an on-off switch
that isn't included in the diagram). The second is that the IR camera on the Wii
Remote can sense a sensor bar placed on or under the display. This gives effectively
four coordinates: three rotations of the Wii Remote relative to the sensor bar, plus a
distance of the Wii Remote from the sensor bar. The third sensor is the accelerometer
(actually the lowest set of nodes in this connected set), which reports the acceleration
of the Wii Remote including gravity. The fourth set is the Wii MotionPlus, which
adds gyroscope functionality and thus provides another set of relative rotations in
a different coordinate system (the device's coordinate system rather than the screen
