Hello Ralph, very interesting concept from a technical point of view. I don’t know anything about Wii Fit. I just looked at their introduction on the web and it seem to me that Wii fit is using weight distribution on a mat as the only signal for biofeedback. What signals will you be detecting? Body position? Muscle tension? Brain waves? In what directions would you want to steer the yoga practitioner? Towards some ideal form of a posture? Who’s ideal?
My feeling is that by the very nature of your device could contradict the underpinnings of hatha yoga. In my view, a hatha yoga practitioner should learn to detect his/her own gross and subtle body signals. At a gross level this is about proprioception, muscle tension, balance, sensations of comfort and discomfort. At a subtler level, it is about breath and sensations of energy. Even more subtly it is about feelings, emotions, and thoughts. The practitioner uses all of these “biofeedback signals” to find a stable yet comfortable position by relaxation of effort and identification with something that is bigger than ourselves (Patanjali yoga sutras II-46 and 47). My concern is that vibration signals given to a practitioner could overrule the more subtle signals that the practitioner is receiving from his/her own body. In hatha yoga, the body is its own biofeedback device! (Teachers and mirrors can help to enhance this device, sometimes!) In this sense, your vibration device might make people do something which looks like hatha yoga, but which is not yoga.
The other concern I have is about the direction you would want to steer a practitioner. For each pose there might be some general rules, but the specifics are a highly personal expression of a practioners perception of stability and comfort at that very moment! How to capture this?
Don’t let me discourage you, though. The process of making a biofeedback device sound really interesting and you will certainly learn a lot about technology and hatha yoga in the process. I also sincerely hope that your efforts, like Wii-fit, will introduce more people to yoga.
P.S. I just realised I have not answered your question about chakras and energies in the subtle body. That is because it is a really difficult question to answer. No practicing yogi really “knows” how the gross and subtle bodies interact. It can only be felt. Why not talk to an acupuncture or shiatsu specialist? They have a vast theoretical and practical knowledge of meridians and pressure points on the body. Alternatively, find an ayurvedic therapist who is knowledgeable in marma therapy. They also know about pressure points (marma) on the body. You might find the literature on chakras a bit remote from your more practical concerns!