There are reported to be varieties of RFID where hundreds of tags embedded in consumer products and stacked on a pallet can be read at a distance of perhaps a few meters. This is reputedly used in inventory control and warehousing in large retailers (WalMart, et.al.) But that is specialized (and EXPENSIVE) technology that is not generally available to amateurs and experimenters.
From my personal experience with the RFID badge readers at the office, I can tell you that they are easily confused if you have more than one RFID tag passing through the portal. The problem is that RFID tags are VERY DUMB little devices. There is no practical way to tell them to "take their turn" in the queue so that you can read them all. It is much like asking a group of children what flavor ice cream do they want. They will all reply concurrently in a caccaphony of information which is useless en masse.Frankly, I don't know how they manage that in those application where they read hundreds (or even thousands) of RFID tags on a pallet. I presume that is why it is VERY EXPENSIVE. And that is why I suggested that it may not be a practical solution. Even the application of implementing RFID tag reading at the finish line of a foot-race is filled with problems that are only managed by extraordinary measures. I continue to believe that it is not a practical solution.
Yeah, that is how I kept losing my keys until I put a hook by the door. If I don't put my keys and glasses and (RFID) badge right there by the door, I will never find them again. :-)Yes, that is an easy thing to do, also. I am currently teaching a class on how to design just such a system, but we are using barcode. The problem of scanning multiple RFID tags, plus the problem of scanning any RFID tag at a distance are the show-stoppers here, at least as I see it.
they are only 4 -5 max 10 ( wallet, keys, cell phone etc), because of that, the proability of becoming a jam would be low I think.