detect my car back home - possible?

my house are now full with automation and i am thinking of going further by detecting my car existance, to perform some action when i back from home, or to alarm if my car when missing.

However i done alot of searching but with no luck.

anyone have done this or any good idea?

I am going to try to use any battery powered zwave devices(such as a sensor), and increase the pulling status to lets say 10 seconds, to check on the device existance, and perform some actions.

There are some prior topics on this. Things like RFID, optical sensors, pinging a small IP device, etc., have been suggested.

Note that typically you cannot poll battery powered Z-Wave devices.