Nguyß╗àn, thanks for your feedback! I think the device could be simple enough so as to sell at cost or for a small profit and still not be too expensive for patients and treatment centers. Charging a small price ($3 or less) for the app could also help to offset the cost of producing the device.
That sounds like a great idea, Melissa. I'd definitely want to implement something like that. Now that I'm thinking about it, a notification mechanic could even be expanded to include medications, exercises, or other treatments. Thanks for the inspiration!