Today's smartphone are a lot powerful and many medical practitioners have started using it as a diagnosis tool. My idea is to do the same but to detect the early signs of Fall.
As mentioned before, the smartphone will record the sensors and camera data while the user walks in a straight line and based on an algorithm it will detect whether the user is at a risk of falling or not.
A caregiver can also use the phone to record a person's walk, similar to the research mentioned in the inspiration article. This will give caregiver on the spot diagnosis equipment to warn the elderly of possible falls.