> > > Which would fail since the cart would detect the RFID tag of the 
> > > first item, note it's weight, and then determine the 
> actual increase 
> > > in weight doesn't match.
> > 
> > First, not when 1 item is a 20 pound bag of flour and the 
> other is a 2 
> > ounce memory stick.  Second, now you're talking about a 
> scale in every 
> > shopping cart along with the computing infrastructure to support it 
> > and probably and RF link.  How much are stores going to pay for 
> > shopping carts, especially when carts are stolen all the time.
> 
> There are already stores out there that have LCDs on their 
> carts with maps of the stores, so adding an RFID reader and 
> integrating a scale isn't that big a deal, especially if it's 
> done in volume (i.e. Walmart).


You don't need scales in the cart.  As the item gets added it talks to the
server (needs to get the price anyway) and gets the weight.

You weigh the entire cart at checkout.

Tony

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