The Nintendo Wii is Nintendo's best-selling home console, and it was a cultural phenomenon when it was first released in 2006. It was due to games like Wii Sports that a huge mainstream audience suddenly found an entry into the world of gaming, and even people who had dismissed the hobby as something for children were finding themselves accidentally breaking their TV sets due to rigorously playing the tennis game and not tying the wrist strap properly.
The success of the Nintendo Wii meant that numerous accessories were released that tried to improve upon the system's motion controls, many of which were released by Nintendo. One of the strangest ideas for a Wii accessory was the Wii Vitality Sensor, which clipped on to the player's finger and measured their pulse.
The Wii Vitality Sensor was first announced at E3 2009 by Satoru Iwata. The Wii Vitality Sensor was a finger attachment that connected to the Wiimote, which could detect things and monitor bodily functions, such as the pulse. According to Iwata, the purpose of the device was to help people relax, though he never specified how the device was going to accomplish this.
The Wii Vitality Sensor seemingly fell off the planet following its initial announcement. It never appeared at E3 2010, despite Reggie Fils-Aime claiming otherwise, and it was only briefly mentioned at E3 2011 when Shigeru Miyamoto said that the device had issues working consistently, but he said that it might still be released in the future.
The Wii Vitality Sensor wasn't officially canceled until 2013 when Satoru Iwata issued a statement to investors claiming that it didn't work as intended and had narrower applications than originally anticipated. According to Iwata, the Wii Vitality Sensor worked with 90% of the people who tested it, but that number wasn't satisfactory to Nintendo and the device was shelved.
The question that many fans are still pondering is: how exactly would the Wii Vitality Sensor have worked with any compatible games? How would the device have helped people to relax? There is no evidence of any games existing that were designed with the device in mind, so no one is really sure how it was supposed to work. There was at least one game that attempted a similar feat, but its applications were the opposite of what the Wii Vitality Sensor was going for.
The Wii Vitality Sensor might seem like a strange concept, but it was similar to a device that Nintendo had already released in Japan. Tetris 64 was a Japan-exclusive title that came bundled with a device called the "bio sensor", which connected to the Nintendo 64 controller and had one end clipped to the player's ear. Tetris 64 had Bio Mode, which increased or decreased the speed of the game based on the player's heartbeat. It's possible that the Wii Vitality Sensor could have had similar applications in titles of the console's own.
The fact that Nintendo couldn't get the device to work properly on a system with an install base as large as the Nintendo Wii means that we likely won't see a different version of the Wii Vitality Sensor in the future, as the potential audience might not be there to make it profitable. The Wii Vitality Sensor feels like one of Nintendo's many wacky ideas that came out of the company during the boom period of the Nintendo Wii/Nintendo DS when the company was trying out as many ideas as possible during the time when experimentation was encouraged. The Wii Vitality Sensor is just another example of the peculiar ideas that could only emerge from a company like Nintendo.