The title and above description would make one think this has something to do with Wii Fit, but the claims are not so limited. For example, claim 1 recites:
1. A system for tracking movement of a user, comprising: a first communication device comprising a transmitter for transmitting signals, a receiver for receiving signals and an output device, said first communication device adapted to be hand-held; a processing system, remote from the first communication device, for wirelessly receiving said transmitted signals from said first communication device, said processing system adapted to determine movement information for said first communication device and sending data signals to said first communication device for providing feedback or control data; and wherein said first communication device receives and processes said data signals from said processing system and wherein the output device provides sensory stimuli according to the received data signals.
Claim 1 indicates that the first communication device is hand-held, which would appear to relate most closely with the Wiimote, not the Wii Fit. Claim 50 (the only other independent claim), also appears to be describing the Wiimote:
50. An apparatus for use in tracking movement of a user, comprising: a transmitter for transmitting signals; a receiver for receiving signals wirelessly from a remote processing system; wherein the apparatus is hand-held; wherein the receiver is adapted to receive feedback or control data signals from the processing system, the feedback or control data signals derived from processed information including movement information of the apparatus; and wherein the receiver receives the data signals from the processing system and wherein the apparatus processes the received data signals to provide feedback or control information to the user.
The '151 patent was filed July 22, 2005, and the earliest possible priority date of the '151 patent is July 29, 2004. The Nintendo Wii was launched November 19, 2006, and was certainly in development for quite some time before that, so I am willing to bet that the validity of the '151 patent is a major issue in this case (in addition to the alleged infringement). Nintendo is sure to argue that the independent claims read on any motion sensor system, and Nintendo was not the first to use such a system (although Nintendo was arguably the first to "successfully" incorporate such a system into a popular game console, which is why they are being sued).
Here is a representative figure from the patent:
The case is Motiva, LLC v. Nintendo Co. Ltd. et al., docket 6:08-cv-429, filed Nov. 10, 2008, in the Eastern District of Texas (Tyler Division). We will add the case to our tracker list and keep you posted.