Re: Disabling RFID by mains force

["Dave Howe" <[EMAIL PROTECTED]>]

Chris Fleming wrote:
> Actually there are protocols that can count the number of items being
> scanned at any one point in time, even when these have the same ID.
Interesting - do you have any online references?
remember we are talking about a number of RFID tags, in a 3D volume that
could well contain an assortment of metal reflective surfaces, where worst
case only the left and right hand "panels" (possibly the floor too, if the
unit is seated into the flooring) are available for receivers/emitters.
Possibly this can be done in a fully enclosed volume - say a "cupboard"
arrangement where you insert trolly, close door, and scanning takes
place - but it seems very hard to me.

> So using the supermarked example, if all the tins of beans have the
> same ID then the scanner can count that you have 10 tins of beans.
> This would be much simpler to implement that a varying ID scheme
> as you won't need a seperate entry in a Centralised database for
> each item for sale.
I have problems with that too. having the same code for each item in a
group, especially if the groupings are per-batch, seems to me to indicate
that the RFID tags must be programmed at the station that adds them to the
product (or pre-programmed in batches per-destination, carefully kept
separate before use at the station, and flushed for each separate batch
(assuming you want to keep track of expiry dates and so forth per-batch
too)
if each RFID has a separate but unique ID, it is simply a case of adding a
scanner to the station, so that the RFID is scanned (and added to a
database) just before being added to a product - then any tag can be
scanned (at random from a batch - just point the scanner at the batch
container) and dereferenced to give the batch while in transit, plus
allowing exact inventory control and identification of batchmates if this
is required (for product recalls, say) - this avoids all the expense of
producing, labelling and handling specially grouped RFID tags (or
field-programmable ones), as the machine that makes them can simply churn
out thousands, each with a unique serial number, and not have to care what
the end product will be.