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Let's suppose we have a suitcase containing some RFID tagged objects. With a reader contained in the same box, I periodically poll the content in order to check if something is removed from the suitcase. Removed means at a distance, lets'say, >1 m. Is that strategy possible with RFID? Any idea on how to achive that otherwise? Problem is we have to indentify precisely a set of items contained in the suitcase, and understand when one of these is removed from the case, even by is id, then returned.

ADDITION Suit case must contain all what we need for the tracking. We can't rely on triangulation infrastructures in place. As a semplification, is acceptable to have the suitcase partitioned: would in this case an NFC antennas matrix help?

EDIT I'm a programmer, not an electronic engineer so I'm definitely ignorant. If there is some obvious solution to track items in a suit case, in term on when a specific item is extracted ( not stolen, so not gone at undefinitely far distance ) , any idea are welcome. Solution based on RF signal based seems IMHO a little too weak, but if you say it will work, I will try. Maybe some matrix of NFC receiver would work? Is there some solution I can buy for try? Surprisingly my googling on the topic did not produce satisfying results.

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  • \$\begingroup\$ Are battery powered RFID tags a possibility? Or are you limited to passive designs? Also are you limited to either near-field or far-field RFID tag types? \$\endgroup\$ – DakotaD Jul 10 '14 at 16:29
  • \$\begingroup\$ @DakotaD if the tags are small, let's say about 1cm, it will be ok. if there is other optio than RFID, will be ok :) \$\endgroup\$ – Felice Pollano Jul 11 '14 at 5:41
  • \$\begingroup\$ I'm going to have to agree with Andy aka, the question needs to be cleaned up and more technical details provided before it can be properly answered. There are many types of RFID and it is not immediately obvious that RFID is he proper solution to the problem. \$\endgroup\$ – DakotaD Jul 15 '14 at 16:38
  • \$\begingroup\$ @DakotaD I posted because I definitey ignorant. In the question is stated that if RFID is not the answer, any other answer would help. \$\endgroup\$ – Felice Pollano Jul 15 '14 at 18:33
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The closest you could come to what you want would be a reader with a transmitter which has variable output power (and I don't know of any that do). If you step through different power levels and keep track of which items "disappear", you might get a rough idea of range. That said, it would not be accurate. It would depend on geometry and shielding (inadvertent or otherwise).

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A battery powered ultra-wideband (UWB) tag with at least three base stations to triangulate the tag position should give you the ~1 meter accuracy you need. Dynamically changing environments with lots of metal would challenge the triangulation. Of all the possible RFID solution this would be the most expensive and most complex.

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  • \$\begingroup\$ +1, but unfortunately can't use that, see the edit in the question. \$\endgroup\$ – Felice Pollano Jul 16 '14 at 4:33

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