Tony Smith wrote:
>>> Everyone I know checks their receipts.  Even if most don't now, 
>>> they're going to start when they repeatedly get home with items in 
>>> their cart that were added by pranksters and hear horror stories of 
>>> all the items people paid for because the scanner read a stray tag.
>>>
>>> Also, you can wait in line behind me and people like me a 
>>>       
>> few minutes each 
>>     
>>> while we check the receipt :).   Then you lose the speed 
>>>
>>>   
>>>       
>> I wouldn't say that exactly, with an RFID system all 
>> checkouts would be 'open' so unless it was the night before 
>> christmas there generally wont be a line at a checkout. The 
>> RFID tags can be placed inside the packaging in many cases by 
>> the manufacturer, preventing casual theft. 
>> How does an RFID system handle things like buying things in 
>> variable quantities, grapes/nuts/coffee etc...
>>     
>
>
> Same way as it's done now. 
>
> Not selling it is the easiest way out, followed by pre-packaging.  You won't
> be able to buy a single carrot, you get to pick from 3 or 4 bag sizes.
>
> It can be handled the same as meat/cheese etc, where it is weighed, wrapped
> and has a custom label applied.  If you look, you'll see the bar code will
> start with '22', and you'll find the weight (sometimes price) of the item
> somewhere in the rest of the number.
>
> For RFID, this means you need to be able to provide programmable (one time)
> ones in the form of a label.  Price (of the labels) is the holdup here.
>
> Another option is to have split checkouts, RFID & non-RFID.  You take the
> fruit & veg out of the cart, they get priced (by a human), push the cart
> thru the scanner to handle any RFID stuff, toss the rest in and head for the
> car park.
>
> More likely is to have the cart weighed & priced.  If there's a mismatch
> (caused by fruit) you go to a normal checkout, and handle the non-RFID (as
> well as errors) there.
>
> Tony
>
>   
why try and encode all that information in the first place?
its rf ID not rf encyclopedia.
1024bits worth of ID should probably cover every possible product that
could be sold You then have a database with the product ID's against the
items. Fruit+veg etc go into the bag, the sales person says this bag has
carrots in it. The computer takes the weight of carrots, and the fact
that it is carrots and sticks that item in the database.
When you get to the checkout your cart is read, That ID is pulled out
and the fact you have 12.2354435kg of carrots is added to your total.
You aren't going to make something programmable cheap enough to work.
I'd wager a coke that any time somebody says they are "programming" a
rfid tag when they wave it near the same device that reads the tag, that
that is what is actually happening. They are just reading the tags value
and telling the computer to associate this ID number with entity X.
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