proximity car key ??
Ok so I work at a car audio shop as an installer and I see so much different stuff and do a lot of custom stuff on cars.. Ive seen a lot of cars that are keyless.. its just a key fob. when you have the fob in your pocket the car knows you are there and lets you start the car with a push button... that stuff is at least 5 years old.. now the other day a new z07 corvette came in for work and the guy handed me a fob to bring it in the shop,, nothing new at first,, but as I approached the car I heard the locks click,, so I stopped and walked back a few feet and I heard them click again... this thing is unlocking and locking on its own as I get near and away from it... And it still gets better.. after walking to and from it a few times to confirm my suspension I finally opened the door... the dash was flashing and it said welcome technician. the key I had was a valet key.. the other key fob I had welcomed the owner by name... this is really cool... I needed both fobs because I was putting a remote starter on the car and both keys are required to program it.. the valet key I had also turned on the traction control and the car wouldn't go over 40 mph... that's a lot from just a key fob... NOW FOR MY QUESTION HERE.... Is this done with rfid or some sort of proximity sensor on the fobs?? I want to build one for my car but just for the locks and push button starter... but I want to retain the factory key also..any ideas or maybe a link to an instructable?? ive searched them but cant find one for my purpose.. lots of rfid stuff though..