My main Android app I care about is my garage door opener. I have a webserver hooked up my garage door opener, so I can open my garage over the network. Combined with a background process doing wifi scanning, the idea's that when I'm on my way home, I pull up to my house on my motorcycle and the garage door magically opens and I back into my garage without taking off my helmet/gloves/etc.
Last night I wrote the background wifi scanning service part and walked around my house and neighborhood to get the signal strengths to the three different APs in my house (and the other ones of my neighbors). Looks like it'll work perfectly. Now I just need to wire up my wifi scanning service with my garage door opening code (simple http client that HMAC signs one-time timestamped URLs).
I just mentioned to evan that it looks like I have enough data to real-time triangulate within my house which room I'm in, since I have enough access points and their signal strengths vary enough. I was going to just make some stupid widget on http://bradfitz.com/ show where I'm at (which room at home, at work, in car via Bluetooth detection, on google shuttle via wifi detection, etc...) even without GPS (or with, if available).
But evan went one further:
make it turn on the lights for whatever room you're in.Hell yes.
that'd be cute.
you could call it "magic wand of light"
Update: See the conclusion in Part 2.