Right so there are many people unsure about what the Wii Vitality Sensor can do and how it does it and well.. how can it translate into a video game!? I'm going to try to explain how it works, what information you can get from it and what possible applications that may have.
The Wii Vitality Sensor is essentially a device known as a Pulse Oximeter. What does that mean? Well essentially they are used to show the oxygen saturation in a patients blood and can also show the blood volume in the skin. It does this by shining light through the finger at two specific wavelengths (through a red and infrared LED) and recording the absorption of both of these lights.
A bit of chemistry for people: If you shine a light at a specific wavelength, particular molecules will absorb more strongly than others at that wavelength. Now if I take 1 L of steam and it absorb X amount of light then we can accurately say that 2L of steam would absorb 2X amounts of light as long as the wavelength was the same each time. Got that? Well the sensor can then detect the amount of light absorbed by the molecules in the blood (the amount of light emitted from the LED minus the amount that reaches the sensor on the other side of the finger) and then workout the volume of that particular molecule.
So now that you hopefully understand that, the sensor is looking for two distinct molecules in the blood: hemoglobin and oxyhemoglobin. The more oxyhemoglobin to hemoglobin there is, the more oxygen saturation in the blood stream. The combination of the two can tell you how much blood volume there is overall. Now where does pulse come into this? Well the monitored signal bounces in time with the heart beat as the arteriols expand and contract with each heart beat. It actually needs this pulse so that it can ignore other tissues absorbing in the same spectrums and putting off the data. So if you're dead, you can't play Wii, sorry :S
It can also tell you a persons total blood volume through a recently worked out algorithm. Kinda cool right? Imagine a game that you had life equivalent to your volume of blood?
So how can all this be used in a video game? What kind of inputs can be shown from the Wii Vitality Sensor's readings?
A players breathing, your pulse changes when you breathe in or out and changes with quick or slow breathing. Holding your breath also changes pulse and blood pressure which could conceivably be shown through increased arteriol blood volume in the fingers.
Possible Applications?
- Controlled breathing exercises
- Breathing fast to build up strength for an attack
- Holding your breath for stealth or underwater action parts of a game
The pulse itself can be used as an input not related to breathing. An increase in pulse can be detected quite accurately as can a drop in pulse. this is the most obvious one.
Possible Applications?
- Keeping your pulse at a sustained level, perhaps controlling the energy used in a bike racing game or jogging game as to not puff out, your pacing and pulse will determine your characters energy level
- Changing AI. An increased pulse could mean the AI should scale back whereas a relaxed player would be bombarded.
- Luigi's Mansion 2. Ghosts that can hear Luigi's fear, they can sense his heartbeat and attack when it gets louder but only try to scare him when it's low. Something along those lines anyway.. Another innovative use would be the insanity meter in Eternal Darkness.
Blood Volume and Oxygen Level. These are the two hardest to place but some odd and really awesome things could come of them. Blood volume in your fingertips increases with blood pressure, you might notice after exercise that your hands aare really warm and even for a while after that but sitting at your desk they're cold. This is because the increase in pressure pumps more blood intoyour hands and therefore there is more blood warming them up. Oxygen level will give information on the players breathing as less oxygen means less breathing and more oxygen means more breathing.
Possible Applications?
- As above, it could help show breathing (I thought breathing deserved it's own section though :P)
- Blood volume could be used in games that has your blood draining as you get damage and blood packs are used to replenish it. The cool thing is it would use your actual blood volume.
- Oxygen levels could be monitored for relation applications and a persons inner health. Perhaps marketing towards smokers and such.
There are quite a few more applications for this technology and I'd like you guys to share your thoughts. What could the inputs be used for to control a game?
