Wii MotionPlus

http://upload.wikimedia.org/wikipedia/en/a/a3/Nintendo_Wii_motionplus.jpg

The Wii MotionPlus is an expansion device that allows the Wii Remote
to more accurately capture complex motion. According to Nintendo, the
sensor in the device supplements the accelerometer and Sensor Bar
capabilities of the Wii Remote to enable actions to be rendered
identically on the screen in real time. The Wii MotionPlus was
announced by Nintendo in a press release on July 14, 2008, and
revealed the next day at a press conference at the E3 Media & Business
Summit. It will be bundled with the sports game collection Wii Sports
Resort, which is scheduled for release in Spring 2009. The device will
also be available for purchase separately. Red Steel 2, The Conduit,
and an EA Sports-branded tennis video game by EA Canada were announced
as Wii MotionPlus-compatible titles.

The device incorporates a dual-axis "tuning fork" angular rate sensor,
which can determine rotational motion. The information captured by the
angular rate sensor can then be used to distinguish true linear motion
from the accelerometer readings. This allows for the capture of more
complex movements than possible with the Wii Remote alone.

The Wii MotionPlus features a pass-through expansion port, allowing
other expansions such as the Nunchuk or Classic Controller to be used
simultaneously with the device. The attachment has a color-coded
mechanical slide switch for locking the clip release. When attached to
the Wii Remote, the unit extends the length of the controller body by
approximately 1½ inches. Each Wii MotionPlus will be packaged with a
longer version of the Wii Remote Jacket to accommodate the added
length.

The Wii MotionPlus was developed by Nintendo in collaboration with
game development tool company AiLive.[82] The sensor used is an
InvenSense IDG-600;[83] designed in accordance to Nintendo's
specification;[84][85] with a high dynamic range, high mechanical
shock tolerance, high temperature and humidity resistance, and small
physical size.[77]

In an interview with video game trade journal GameDaily BIZ, Satoru
Iwata stated that the Wii MotionPlus was conceived soon after the
completion of the initial Wii Remote design, to address developer
demand for more capable motion sensing, but was only announced after
the sensors could be purchased in sufficient volume at a reasonable
price.[86] During a developer roundtable discussion at E3 2008, Wii
Sports Resort producer Katsuya Eguchi discussed the potential
influence of the Wii MotionPlus on the Wii's existing market, stating
that Nintendo was looking at whether the MotionPlus capability will be
built into the Wii Remote in the future, or kept "as an attachment we
only use for certain software."[87]

http://en.wikipedia.org/wiki/Wii_Remote#Wii_MotionPlus