This is a very interesting idea, since it tries to get to the root of the problem for many of the seniors having trouble with falls. My one piece of advice would be to consider the battery life of the object. For those with regular caregivers, or those who still have all their mental capacities, this wouldn’t be an issue. But, for those who have dementia, Alzheimer’s or are just becoming more forgetful in their old age, you’d want to be sure to have something that they could wear for extended periods of time, that charges very quickly or is impossible to forget to wear. An integration with a hearing aid, similar to what you mentioned, would be good for those with hearing problems, but not everyone has that issue. The glasses attachment may be more viable, since poor eyesight is even more common that poor hearing.
This may not be as big of an issue as I think it is, but it is definitely worth considering if you move forward with this idea. Thanks for sharing!
I really like your idea. Stairs are definitely a major issue for falls, and a simple remedy like yours could be a solution that can easily be rolled out and be effective.
You didn't mention it in your write-up, but you want to be sure that the height and length of each step remain exactly the same for each step. There's research that shows that even 1/4" difference in height can cause falls (page 3 - http://www.human.cornell.edu/dea/outreach/upload/Stair-Safety-2-2.pdf) Anecdotally, my mother had this happen to her. Contractors who built new stairs in her home were off by 1/2", and she fell and broke her wrist. Just wanted to be sure you had considered this in your idea.