This post should help you find answer to a number of the early questions:
$1 Refreshable Braille displays are expensive, but a number of attempts have been made by funded groups to replace current technology.
Do not for any reason make a smart cane!
As soon as you can, find some local blind folks you can survey and then talk to one on one (perhaps via Zoom). Pick a problem they want solved, and break that problem down so that you can solve some version of it in a reasonable time frame.
If you can make one or two local people happy, you've made a good start. DON'T try to solve a problem for tens or hundreds of thousands of people at once!
Since you're in biomedical engineering, which I assume emphasizes mechanics, think of focusing on blind and visually impaired folks who may have issues with mobility.
Another idea is to pick up a copy of the catalog from a place like MaxiAids (
$1), see what seems overly expensive, and then design something better. Try to make it at least ten times better.