However, I'm also a software engineer for a medical device company and I spend a great deal of time assessing and mitigating the safety of various operations. Please take care to understand the failure modes of anything you build and attach to your own body. When you get to the point of using an Arduino (or anything else that uses software), the number of failure points goes up dramatically. Try to consider how anything could fail and what the consequences will be.
However, I'm also a software engineer for a medical device company and I spend a great deal of time assessing and mitigating the safety of various operations. Please take care to understand the failure modes of anything you build and attach to your own body. When you get to the point of using an Arduino (or anything else that uses software), the number of failure points goes up dramatically. Try to consider how anything could fail and what the consequences will be.