When I started looking at this project, I didn't really think about the application outside of my own personal use. I don't think I get migraines, but I regularly get headaches that seem to have a trigger of some kind. I think it has something to do with Wednesdays, but I don't have actual data to back that up. They have also seemed to happen around weather changes and my dry sinuses seem to be related, too, which I know is directly related to environmentals.
I don't plan on taking this project as far as I think it could go, but allow me to dream a bit. These sensors could be integrated into a fitbit-sytle wristband, synced with an app on a smartphone with geo-tagging, and aggregated en-masse for statistical analysis. Over time, if a correlation is found, this could also be used to notify the user of a risk based on their personal data. Trends could be tracked across a broad population, and used for research. Ignoring HIPAA and privacy concerns, naturally.
This project is just a few sensors and buttons with a battery so I can collect my data. I may try to write some internal correlation math to see if I can alert myself of harsh conditions I may not be aware of, but that might be pushing it a little bit. As is, I don't think this will change the world, but it could help collect data about migraine headaches that are not well understood.