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RFID 125kHz card readers are very cheap (< 5$) and very simple (USB Plug & Play).

Is it possible to chain / multiplex 20 readers to create a very accurate plug-and-play smart shelf?

What are the limitations?

  • Tags must be 3cm wide
  • Tags must be set at the bottom of item (not on the side of a book)
  • Items can't be stacked
  • How to multiplex reader to have "reader Id" + "tag Id"?

Is there a simple, plug-and-play, low cost smart shelf alternative? Everything I found (UHF reader + antenna + multiplexer) is for > 5000$

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    \$\begingroup\$ Can you "chain" anything that is USB? \$\endgroup\$ – Andy aka May 29 '14 at 22:00
  • \$\begingroup\$ Not sure, USB Tree Handle 127 items max, and have issue with power or bandwidth. I assume thre is smarter thing to do \$\endgroup\$ – Jean-Philippe Encausse May 30 '14 at 4:29
  • \$\begingroup\$ Could you explain what you mean by "plug-and-play smart shelf" in more detail? What do you mean by multiplexing? \$\endgroup\$ – abdullah kahraman May 30 '14 at 6:56
  • \$\begingroup\$ By plug-and-play I mean something really easy to install: plug the shelf on a computer then start reading data using an object oriented language. If I use 20 RFID USB reader (not good idea) I will have to handle 20 USB connections to track that reader 2 is trigger with card id 3 (what a mess) \$\endgroup\$ – Jean-Philippe Encausse May 30 '14 at 8:18
  • \$\begingroup\$ If you don't care about location on the shelf, you could just put one big detector coil around it. If you're hoping to use lots of adjacent readers to locate tags exactly, you'll probably hit interference problems. \$\endgroup\$ – pjc50 May 30 '14 at 15:18

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