Cell Phone "Find Me" mode

I recently had occasion to misplace my cell phone about the house. Of course, had it been on, it would have been a simple matter to call it, but alas I turned it off.

So, my concept requires some kind of sensor which can detect whether the phone has been moved (or at least has changed orientation). It needs to do this passively (without consuming valuable battery). It also needs a simple alarm clock circuit that can periodically turn it on, without drawing an enormous amount of battery power.

In the "off" state, the phone periodically wakes up, lets say every 4-5 hours. When it does, it checks the sensor. If it detects that it has moved, it goes back to sleep. If it has not moved, it turns on and checks for a special form of text message. If it receives this message, it turns itself on and sends a text message which will end up in your email telling you that the phone is now on. At that point, you can call it from your landline and find the phone. If the battery is low, the phone should send the text message and, if not moved with 10 minutes, go to sleep for one hour and repeat until the unit is either moved or the battery runs out. Perhaps it would be good if the wait time were increased with each attempt, in case you were not near your email.

The use case I envision is where you know approximately where the phone is, such as in your home. It would not be effective where the phone has been lost or stolen and it might be in a much larger area.