Self-checkout practice: a pretend machine to scan, bag and pay at

A real self-checkout

• Machines differ a great deal. The screens, the words, the voice and the order change from one store to the next. What follows is how it often goes, not how any one machine works.
• The barcode is the patch of black lines printed on a package or on a sticker. Scanning is passing that patch over the glass, or in front of the red light, until the machine beeps. One beep usually means one item was taken; the screen shows its name and price.
• When an item is not read, turning it so that the black lines face the glass, flattening a wrinkled bag, or moving it a little slower often does it. It is common, and it says nothing about the person holding the item.
• The bagging area. Many machines weigh what is put down beside them, and wait for each scanned item to land there before they take the next one. Lifting a bag off early, leaning on the shelf, or putting down something that was not scanned often makes the machine stop.
• When the machine stops, a light above it often comes on, and a worker comes over. That happens all day long to all kinds of shoppers; it is part of how these machines work, and it is not an accusation.
• A worker is nearby. Self-checkout areas usually have someone watching over several machines. Waving, or pressing the help button on the screen, is an ordinary thing to do, and so is saying “this is my first time”.
• Things with no barcode, such as loose fruit and vegetables, are usually found with a “look up” button: by a picture, by typing the first letters of the name, or by the small number on the sticker. Things sold by weight are put on the glass or the scale; things sold by the piece are counted.
• Some things need a worker’s OK before they are sold; which things is up to the store and to where it is. The machine stops, a worker looks, sometimes asks for an ID, and the checkout goes on.
• Taking a thing off the list is often something only a worker can do. If an item was scanned twice or the price is not what the shelf said, the help button is the way.
• Paying. Card payments are usually made on a small card reader beside the screen. Not every machine takes cash; those that do have a slot for bills, a cup for coins, and a place where the change drops. Some lanes have a sign that says “card only”.
• Questions that are not about paying. A machine may ask about your own bags, a rewards or phone number, rounding up for a cause, or an email for the receipt. Each can be answered with no or passed over, and the checkout goes on the same.
• The lane with a cashier is still a choice. Nobody has to use a self-checkout. A store worker can also be asked to ring things up, or to stand by for the first time.

How the lessons work

• The pretend machine is the dark box. The pale part at its top is its screen: it shows what the machine is asking, the list of what has been scanned with the total, and its choices, which are buttons on the screen itself.
• Three buttons stay under the screen the whole time, as on many real machines: “Look up item”, “Finish and pay” and “Call for help”.
• The box with the dashed edge is your basket and your hands. Each thing in the basket is a button: “Scan: …” stands for passing its barcode over the glass.
• “Put it in the bag” stands for setting the item down in the bagging area. The pretend machine takes no new item until the last one is there.
• The buttons are pressed with a mouse, a finger, or the Tab and Enter keys.
• Paying is one press. “Use the card reader” stands for the whole card payment, and “Put the cash in” puts in made-up bills for you. The card itself has a page of its own: Card reader practice.
• The yellow line under the machine says what the last press did, and what the machine is waiting for.
• A choice the step is not after changes nothing: the machine stays on the same screen and the yellow line says so. A real machine would go on with that choice.
• The steps say no to the rewards number and to rounding up every time. That is only so that saying no gets practiced; what to give is yours to decide.
• The pretend machine counts nothing against you. An item that is not read can be scanned again as many times as it takes, and the pretend worker always comes.
• “Next step” answers only when the step is done. Until then it is gray. On the last step of a lesson it says “Finish the lesson”.
• The page waits. There is no countdown, and nothing is timed or counted. “Start this lesson again” asks for another basket and other prices.

Every time the page is built, a program makes 24,000 lessons, half in English and half in Spanish, and walks through their 56,000 steps, pressing the buttons itself: that the choice a step is after is on the screen, that no step is done before it begins, that the right presses in order end the step, that every other button, every other choice and every other thing in the basket leaves the machine where it is, that no new item is taken until the last one is in the bag, that a thing with no barcode cannot be scanned, that each price by weight and by the piece, the list, the total and the change come out to the cent, that the total is on the screen before any money is asked for, that everything in the basket ends up in the bag, and that both languages ask for the same presses.

What this page does not do

• It buys nothing and pays for nothing, and reaches no store and no bank.
• It is not any real machine. A real machine’s screens, words, voice, order and buttons will be different.
• It does not practice the card reader’s own screens, coupons, store apps, paying with a phone, a hand-held scanner, bag charges, sales tax, or returning an item.
• It does not know the prices, the rules or the programs of any store, which things need a worker’s OK where you live, or what any benefits card will pay for. The store’s workers are the ones to ask.
• It cannot practice the hands: finding the barcode, how to hold an item to the glass, opening a thin bag, feeding a bill into a slot.
• It has not been tried by people. A program tried the page with a mouse and a keyboard in one browser. It has not been tried on a touch screen, with a screen reader, a switch or an eye tracker.
• It keeps no record of lessons done, gives no certificate and makes no promise about how any real checkout will go.