I am trying to setup a system for RFID.
I am looking for an affordable system with a range of 3-6 feet. As an example, if I have a tag in my wallet in my pocket all I will need to do is walk up to a door to be recognized as opposed to having to remove the card, swipe it, etc. I see no reason in using rfid over a magnetic card system if I have to manually remove it and use it within milimeters or centimeters of the reader. Yes, the security is still better, but that's not what I need it for.
I was looking at the Parralaz ones, but they don't have any in that range
Please let me know if you have any suggestions that would work for what I need.
thanks
Have not seen readily available RFID readers that can handle more than a few inches using passive tags. Requires a lot of output power (remember inverse squares law!) and very sensitive receiver. Active tags exist, they're used in things like electronic toll booths. Active tags require a battery which eventually runs out. The tags and reader systems are generally not cheap.
I have heard of them, just not in the easy to get form like sparkfun or parralax.
If I had to go active, I could just use custom RF transmitter. cheap and easy through sparkfun. I was hoping for passive, but I guess that might not be a choice. Hopfully I will be able to find something though.
as long as you can get an RFID reader unit from somewhere, all you need to really do is make much larger induction coil, and modify the reader so it provides larger current to the coil and/or amplifies any signal received.
From what I can tell a 2 meter read range isn't out of the realm of possibilities at a reasonable price. The standard 125kHz systems might be a bit underpowered for that, but I should be able to do it with a 13mHz system and a fairly decent antenna or a 900mHz system for larger read distance if I get the chip and make the board myself. Atmel has a chip in that range. ATA5590, it's not listed on their site though for some reason.
The locations I need to use can have a nice 2 foot diamater circular antenna without issue, but how would I add extra power to them without messing up the signal to the reciever?
I'd prefer to use the 125kHz if possible, but I don't want to invest too much if it's not going to work and have to do the better system anyway.