More RFID Thoughts: Part 2

Like an errant RFID tag, I can't seem to turn off thinking about RFID.  Hopefully, thoughts on RFID will taper off over next few days.  Until then, I continue to flush them via this blog.

One detail I am missing is how a dense cluster of RFID tags can be read by a RFID reader.  For example, if individual pages have an RFID tag, how high can the stack of papers be and still be scannable with an RFID reader?  If 1000 RFID tags emitted 64 bits of information at the same time, can an RFID reader process them all?  Not likely.

An obvious yet imperfect solution is to program some random delay values into each RFID so chance of all of them firing at the same time will be lowered.  RFID reader also needs to read multiple times to be reasonably certain that every tag is read.  Is this how RFID works?

An interesting anti-RFID device is a random RFID generator that floods an area with randomly generated RFIDs.  While RFID manufacturers probably can't copyright ranges of 64 bit numbers, FCC is likely to outlaw such devices.  It's interesting to think about though.

One application of RFID maps location to individual RFIDs.  Nice and cheap positioning solution.  In this case, RFID reader is attached to some movable objects such as containers or crane arms.  But then sabotage is as simple as replacing real RFIDs with fake RFIDs.

Possibility of fake RFIDs bring up another question: how does RFID readers handle two conflicting responses?  If a fake RFID tag response faster than real RFID tag and RFID reader is programmed to accept the first one only, I can buy expensive goods cheaper.  Looks like one can't just grab something and walk out without a clerk making sure the RFID matches the merchandise.