An anonymous reader writes: I have an older (90+) relative who is experiencing mental decline. He's still fairly functional (you can have a decent conversation with him, and he's amazingly positive for someone in his condition), but his memory of anything recent is terrible. He's in an assisted living center, but he's having serious trouble for example finding his way to the dining hall and back to his room. He has visitors daily and the staff are supportive but 24/7 oversight is not an option. I am looking for a navigation system suitable for use indoors that will help him move around. The distances involved are short, and his schedule is pretty regular so it would be OK to have a schedule of where he usually is at a given time (lounge, dining hall, room) and a big green arrow that always points out which way he should go to get there (so it would need to accommodate doors and hallways etc, not just the straight line direction). Is anyone here aware of such a system? I've thought of trying to write an app for a smartphone but I'm not sure if GPS is really the way to go, seeing as it's indoors. Also, battery life would be an issue — he would have trouble remembering what to do if it stopped working and I'm not sure if he'd remember (or be able) to connect a charger. For the same reason it would need to be pretty bomb-proof — he's not in position to troubleshoot if it fails.