Evan Schuman's StorefrontBacktalk

The problem is with how Kinect finds people it needs to follow. Kinect puts out a field of infrared dots with a laser and looks at the resultant distortion, Wheat said. “Above a certain light level, it washes out those dots,” he said. In effect, it would make the customer suddenly invisible to the cart.

Avoiding parking lots is probably a good idea anyway. The carts won’t likely take well to rain or snow. Besides, the Kinect portion costs about $150, the motor system about $1,000. And then there’s the cost of the tablet and the cart itself. Yeah, you probably don’t want shoppers leaving the store with them.

There’s also a question of whether customers in an environmentally friendly chain such as Whole Foods would appreciate wasting energy on a battery-powered cart. The current carts run on a pair of 12-volt batteries (that’s mostly for the motor and is above and beyond the power needs of the tablet) and the testing model will use up all of that juice within 2 to 3 hours, Wheat said.

The cart’s interface with the customer seems to be primarily through speaking. Again, that’s nice in a demo. But in a crowded aisle full of rush-hour shoppers, we’re not so sure the cacophony of a dozen carts talking past each other would be optimal. Beyond the annoyance, it would likely undermine any store attempts at creating a pleasant, music-enhanced shopping environment.

Also, what if one customer’s cart reacted to a verbal instruction intended for a different cart? That could create a different type of chaos with well-meaning customers, let alone what a not-so-well-meaning person could do to make trouble. (Hey! Why is everyone looking at me?)

Wheat said his team is also concerned about store aisles crowded with shoppers and then “having all of the carts talking at once.” Chaotic Moon Labs is trying to at least help the units know which voice they are supposed to obey.

“The carts themselves have microphone arrays” and they calculate the angle that its master’s voice should be coming from.

Now to the good stuff. The consumer begins this cart interaction by showing the cart his/her loyalty card, which the cart apparently detects via an RFID reader.

That’s another heads-up that this is an odd fit for Whole Foods. The $10 billion chain, with 317 stores in the United States, Canada and the United Kingdom, shuns loyalty cards. Heck, last year the chain swore off accepting checks. Why? “We simply don’t want the burden of having all that information,” Letton said at the time.

But this cart seems to have no such problem with data retention. It leads the customer through a journey of fulfilling her already submitted shopping list, presumably created through a mobile app or on a Web site and wirelessly accessed by the cart.