How Do Scanners Read Barcodes?

You’ve all been shopping and have seen someone ring up an item with a barcode scanner, or maybe you’ve worked as a cashier and have been the one ringing up the purchases and using the barcode scanner. In fact, most of you have probably used a self-checkout in a grocery store and haven’t even paid attention to the fact that you were using a fixed barcode scanner. If you look around you, you’ll begin to notice that barcodes are actually a part of your daily life. Shopping, checking out books at the library, receiving your mail, the list goes on and on. But do you really know how it works? What actually allows a barcode to be read by a scanner?

Barcodes are read by sweeping a small spot of light across the barcode symbol. The barcode’s dark bars absorb the light while the white spaces reflect the light. This reflected light is then converted into an electrical signal by a device within the scanner. The electrical signal matches the printed barcode pattern exactly and holds all of the data that was originally encoded in the barcode. The last step is to decode the electrical signal back to the original data and this is done through the use of speedy and inexpensive electrical circuits.

Here is a short clip I shot showing what a UPC looks like when scanned by a Symbol barcode scanner.


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