The Wii Vitality Sensor is a cancelled accessory for the Wii. Announced by Satoru Iwata at E3 in 2009, not much is known about the Vitality Sensor and how it would have been integrated into video games. It has been suggested by Iwata that it would be used to relax the player, telling them their heartbeat and about their body.
The Vitality Sensor was revealed at E3 2009 by Satoru Iwata, though no software that utilized the device was shown. After the announcement was made, Iwata on various different accounts confirmed that they would show off games for the accessory at the following E3 in 2010.
During E3 2010, the device was not shown or even mentioned. When asked why, a Nintendo spokesperson said that they didn't feel it was the right time to show it off just yet, saying that they would at a later date. It has been speculated that Nintendo chose not to show it after a similar product was revealed by Ubisoft the night before at their press conference.
On July 5, 2013, it has been confirmed that the Vitality Sensor had been cancelled due to testing issues.
"We have not been able to launch it as a commercial product because we could not get it to work as we expected and it was of narrower application than we had originally thought," Satoru Iwata told investors. According to Iwata's estimates, approximately 90 out of 100 people were able to use the Vitality Sensor without a hitch, though he (thankfully) requires that it work with "1,000 of 1,000 people." However, he admitted "but [since we use the living body signal with individual differences] it is a little bit of a stretch to make it applicable to every single person." He'd still love to make the Vitality Sensor a reality "if technology enhancements" allow, but thus far, testing renders it "insufficient as a commercial product."