Well where are you in the world? I would definitely suggest rolling by your local hackerspace and looking for some assistance in getting yourself motivated, an

Well where are you in the world? I would definitely suggest rolling by your local hackerspace and looking for some assistance in getting yourself motivated, and navigating the harrowing experience of building out your own tool collection / parts collection as well as some of your skills. Sourcing components and tools as a hobbyist, garage inventor, or even small design firm is very different from sourcing parts as a large institution or as an enterprise. The factors of scale change the playing field drastically. Many of the smaller kit builders and maker types have a shared knowledge regarding this sort of limited run development that you are endeavoring to pursue. That being said, the key benefits for you that a major scholastic environment can provide you outside of tutelage is access to a robust machine shop, capable electronics facilities, and more important than all of that... protection from litigation in the patents you file. Many graduate and even undergraduate programs offered by major universities actually will stipulate that any patent you file while at school, regardless of whether it's a personal patent or something completely unrelated to school, will be protected by them, their legal war chest, and their patent warchest. This is a huge selling point for some schools. ASK ABOUT IT. Also, many schools have start up incubators of their own, or a network of people who can help you find funding. A friend who left stanford graphics lab took advantage of their start up program where they offer you use of facilities and space on campus in return for a percentage stake in the venture... they also will provide you with assistance in using their alumni network to score capital. These are just some immediate thoughts. But I definitely see some values in going back to university that have no relevance to the actual classes you might take, but more with getting things done in your R&D. Definitely regardless of what you decide your level of commitment is, don't get discouraged. There are far too few people with medical certification and experience turning their eyes towards prosthesis and other technologies that assist the disabled. And while there's money to be made there, more importantly there is a lot of good that can be done. The things that help someone who is confined by their disabilities can be for more huge to the people who use them, than us. I know a number of engineers, good ones that would be interested in helping people the way you are suggesting. It's a job that one can draw immense satisfaction from.