I stumbled on this today, and it got me thinking about using something like it in my Jeep as a kill-switch type setup.
Ideally, it would trigger a relay that would allow the engine to start. Maybe by wiring it into the coil.
**broken link removed**
Trouble is, the 3" range isn't nearly enough. It has to be good for at least 2' or so, but I can't seem to find anything like that available.
Would it be possible to use an active RFID tag with this sensor, or... Are there any other ways to get some more range out of it?