Eli5: how a scanner at the store can detect when one item hasn’t been scanned (which only has a barcode on it) while dozens of the same item can be leaving at the same time
In: Technology
Inventory control tags are little strips with a couple of pieces of metal in them. They are magnetically charged, and can be read by a field such as the one created by the pillars at a store entrance. The tags are also sometimes very flag square-ish spirals that can be very easily hidden in the packaging.
When an object is scanned at a cash, the act of scanning it also brings that inventory control tag near a field that demagnetizes it.
The barcode scanning itself is unrelated to the inventory control, aside from the fact that it is set up in such a way to simultaneously deactivate the tag.
Weight. Just past the scanner is a scale that weighs the scanned product. Along with the SKU and price the barcode also maps to a product weight. Scan one item but set down three? The weight difference alerts the scanner.
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