RFID Entry System
I've been looking around a lot and finding information regarding RFID tags and readers. What I want to do is slightly intense...
When I come within 10 feet of the car, I want the car to turn on and the doors to unlock. Simple plan so far with readily available technology... but I want more. I want to never need to worry about a set of keys again regardless of whether I'm wearing a certain thing or I'm naked. For this, I want to inject an RFID tag into me. With a tag injected, it cannot run on batteries and therefore could not be active RFID. It would need to be passive.
There are cheap kits readily available on different websites which are capable of reading such RFID tags from within 4 inches. I need something like 10 feet though. I have the programming end of this down, what I really need is the physical reader which can read within that distance. I've seen plenty of readers which can read far beyond that distance but they all cost over $1,000. Anyone know of any readers which work within 10 feet?
Any other input is also appreciated...
Most of the cheaper stuff for greater than 4ft range are active fob devices. You're not going to be able to find anything with that kind of range for cheap, or low power. It'd probably drain the batteries in your car fairly quick.
Looking around I find this product here:
It gives up to 15 meters and requires 6 watts. So it seems as though power isn't such a big issue. I have an 85 amp-hour battery which would let that baby run for over 7 days. I'm not afraid to go bigger on the battery for one of these things, if need be.
The problem with that site is they don't list product prices and they haven't responded to my inquiries yet.
This stuff is expensive for ranges over a few inches. I did a lot of research on this recently and didn't find anything that looked too promising for a decent price. I came to the conclusion that using bluetooth or xbee would be easier, though it would be more work.
My idea called for a receiver to be connected to the alarm somehow and to deactivate the alarm and unlock the doors when the transmitter came into range and was able to perform a handshake. Then the start button would activate, allowing me to simply walk up, open the door, hit the button, and drive off. The transmitter would be small and rechargeable and go on my key ring. I've yet to actually build anything though, all in due time. And also, being deployed, I don't have access to my truck to figure out how I could operate the alarm in this fashion. But the whole system could theoretically be built for fairly cheap (xbee modules can be found for around $20 or less, plus a couple microcontrollers, a few relays, and a few other parts). Although if this stuff is over your head, you might want to keep looking for other options.
BTW, I also found somewhere a nifty thing that will sense touches through glass. Combined with the system described above, along with shaved door handles, this could be something interesting...
I looked into this too. I would extend this to my front door and garage door as well. I would not have it auto open anything but the car door. It would start my car computer up. for the garage and door a button press would activate the circuit. Because of this I would not use keys and would have the rfid in my wallet. I decided it was too expensive but if anyone finds cheaper ones i am would be interested.
See, for me, I'm controlling this with a sheeva plug and fusion brain. If you haven't heard of the sheeva plug it's a small embedded computer. So setting it up wouldn't require anything except the receivers and maybe some power source, but other than that, I wouldn't need a microcontroller or anything. The issue with xbee or bluetooth or anything along those lines is that I actually want this thing injected in me, so I can't do batteries.
I've actually just found this guy:
It gives me a meter for $290 bucks. That's the cheapest I've found yet. Still expensive though.
My idea now is... if I get a low powered one that has a UHF antenna, maybe I could use a UHF TV signal amplifier?
Sparkfun had a tutorial and a product on this a while back I looked at. I couldn't find it again real quick, but here was one tutorial someone there wrote up on DIY
even if you dont go that route, it gives you ideas. I started working on this myself in my car but instead of with rfid I tried using either an xeebee or hacking something up with a blueSMIRF
www.iautomate.com has a starter kit for $600
Thinkgeek has a a really good one for $99.
Supposedly the thinkgeek one even comes with an implantable tag. Only a 4" range though. I think the range is negligible- how long does it take you to cover 10'?