Self-Service Scanning

January 20, 2004 1:49 PM

The U-Scan stations: how do they know that the item you just scanned is the actual item? [More inside]

My co-worker thinks that they know what every item should weigh based on its UPC. Thusly, the location where you place the items you have scanned is just a big scale. While this seems plausible to me, I want better evidence. My Google searches have only brushed the subject - no obvious text saying how it knows what item is what. Anybody know for sure?

posted by internal to Shopping (19 answers total)

The platform is definitely a scale: the ones at my grocery store have signs saying as much, and it'll beep at you if you put items you didn't scan on it (purse, the handbasket you were carrying the items in, etc.) I don't know, however, whether it knows how much each item should weigh, or if it just detects that some weight was added to the scale.
posted by DevilsAdvocate at 1:57 PM on January 20, 2004

I don't know, but if people aren't paying attention, it's a great way to get free groceries. I don't see how these can possibly save the store money.
posted by agregoli at 2:02 PM on January 20, 2004

This and this both seem to confirm your co-worker's theory.
posted by Pockets at 2:02 PM on January 20, 2004

Hmmm, so if I buy a cheap bottle of wine, save the UPC code and stick it on an expensive bottle the next time I'm shopping...Bwahahahaha!
posted by strangeleftydoublethink at 2:20 PM on January 20, 2004

All the uscan stations in my local grocery stores have at least one employee overseeing every 4 stations. I always figured they were the honesty cops.
posted by vito90 at 2:30 PM on January 20, 2004

I think, agregoli, that the money they save by having one less cashier cancles out any money lost because of a few dishonest folks who've discovered they can beat the system.

As for how they work, I'm pretty sure a scale is involved. I think my Home Depot even has the bag on the scale so it can tell if you've put something extra into the bag.
posted by bondcliff at 2:31 PM on January 20, 2004

The platform where you bag the groceries is most definitely a scale. If the item you scan and place in your bag doesn't reflect the weight in the database, it'll beep at you. They usually do have a customer service person overseeing up to as many as half a dozen of these areas. I'm guessing since many grocery stores are unionized and cashiers make big money, putting one management person in a position to replace six cashiers is a HUGE savings. Plus, I've always found the self-scan lines to move faster because (1) people who use them are more competent at scanning and bagging and (2) people are buying fewer items. Personally, I love them.
posted by marcusb at 2:47 PM on January 20, 2004

I really doubt they have a database of the weights of all their items. I always guessed they have two scales - one under where you scan the item and one under the bag you put it in. The system beeps if it registers you put a weight of something in the bag to take home that you didn't put on the scale by the scanner first.
posted by straight at 6:33 PM on January 20, 2004

strangeleftydoublethink: Yes.
posted by whatnotever at 6:34 PM on January 20, 2004

I always guessed they have two scales - one under where you scan the item and one under the bag you put it in

Yahbut, that only works if you put the item down to scan it. At the local Kroger (pron. "crow-zhair"), if I'm self-scanning my stuff isn't hitting the plate. I can rotate the prey item around more axes more quickly if I keep holding it up, so the scanning gets done faster. And the machine doesn't complain about it.

It also works if you're using a cart and the machine only ever sees the scale under the bags (ie, the output scale). So I think it's gotta have a weight field in the database.
posted by ROU_Xenophobe at 6:58 PM on January 20, 2004

Boycott them entirely until they offer a discount for doing *their* job
posted by Fupped Duck at 7:22 PM on January 20, 2004

I really doubt they have a database of the weights of all their items.

When they already have a database of the prices, it's trivial to add the weights. It's a two-step process that I imagine goes something like this:

1) Add a column to the database table for weight.
2) Tell your suppliers that if they don't provide the data, you won't carry their products anymore. Since they already have this data because WalMart gave them the same ultimatum, they will give it to you.
posted by kindall at 8:29 PM on January 20, 2004

I suspect the weights are a spot-check system. The other day I bought a huge box of cat litter and put it on the floor after scanning, and the machine didn't care.

Either that or it's smart enough to know that some items are too big to bag.
posted by mmoncur at 10:18 PM on January 20, 2004

yes, there is a guy watching you as you check out. and if you notice there is a camera as part of the u-scan that is looking down at the scanner and at your purchases. i was watching the person in charge of a pod a couple days ago and was surprised at the speed at which he was interacting with the scanners without the customer knowing. someone would make a mistake, and he, watching you, would fix it very quickly. for example that cat litter thing may have been an override by the clerk, the guy i was watching was doing stuff like that pretty rapidly.
posted by rhyax at 10:27 PM on January 20, 2004

Yes, those stations expect a certain weight (And they're also piss-poorly designed from a usability perspective. How many of you expect paper bills to shoot out at your knees?).

I know this because our local grocery store has been too dumb to program it to ignore cases of pop. This means you either have to bag a case of pop (not going to happen), or bug the cashier lady EVERY time you have one to unlock the machine (when you have 5 or 6 too big to bag items this gets really annoying for both). Placing an incorrect weight on there instead doesn't seem to work.
posted by shepd at 11:11 PM on January 20, 2004

I think they work great for 1-2 small items, and you don't have to have an artificial human transaction with a stranger. If you remember the scene from Raiders of the Lost Ark, when Indy puts a carefully weighed bag of sand in place of the gold idol--that's pretty much what will happen if you try to switch labels, so don't even think about it.

The thought of these replacing all checkers makes me ill. Because people (including me) are just stupid.
posted by mecran01 at 6:13 AM on January 21, 2004

I am pretty sure k-mart in Parma ohio doesnt even have scales as it doesnt matter where the groceries sit or if they are removed before payment. While the Krogers that i shop will tell me to place the item back in the bag... if it feels the item removed... or it will say please scan the item before placing it in the bag. I dont know if it knows the weight before the item is added to the scale but it definately remembers the wieght after.
posted by Recockulous at 9:48 AM on January 21, 2004

Please place the item in the bag. Please place the item on the scanner and wait. Please enter the quantity now. Do you have any coupons? Do you qualify for a senior citizen discount? Do you have any items under your cart? Please place the item in the bag.

I think Harris Teeter either has this aforementioned "weight database" or just demands that you put something on the scale to the right of the scanner after you scan it. I scanned two bags of wood and it demanded I pile them up on the scale since the high-dollar supervisory employee was too busy... I don't know, staring at something else to notice that I was attempting to create a giant, wobbly, top-heavy grocery pyramid at the U-scan.

I don't know why I didn't go to a human for that load. Usually if I have more than a small basket or too many produce items with no barcode I avoid the U-scan.

Please place the item in the bag. I want to ring her well-modulated neck sometimes.
posted by jennyb at 10:10 AM on January 21, 2004

Yes, those stations expect a certain weight (And they're also piss-poorly designed from a usability perspective. How many of you expect paper bills to shoot out at your knees?).

I know this because our local grocery store has been too dumb to program it to ignore cases of pop. This means you either have to bag a case of pop...

Well, it sounds like the ones where you shop are indeed poorly designed, but that's not the case with all of them. On the ones they have at Meijer, bills, receipts, etc. come out around upper-body height. And, the scale is a pretty large metal platform--it has the bags on it, but has lots of room beyond where the bags sit as well, so you can put large items on the scale without actually bagging them.
posted by DevilsAdvocate at 10:45 AM on January 21, 2004