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Hello App Inventor!: Android programming for kids and the rest of us by Paula Beer and Carl Simmons

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Chapter 10. Barcodes and scanners

Barcodes have been around since the 1970s, and there aren’t many products now that don’t use them. No doubt you’ve used barcodes in the supermarket at the self-checkout registers.

Barcodes are groups of black and white lines that represent numbers according to the widths and spacing of parallel lines. They can be read by either special optical scanners or smartphone cameras that provide product information that can be read by a computer. The barcode is considered to be one-dimensional (the lines travel in one direction). A QR code is a two-dimensional barcode (a matrix code). To read such codes, make sure you ...

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