How do barcodes work?
The barcodes you see on products at the supermarket encode information in patterns of wide and narrow black lines. When a barcode is moved over an optical scanner, the device detects the sequence as a series of long and short impulses.
Though the origins of barcodes go all the way back to the 1960s, the technology for reading them is developing all the time. The latest readers use lasers. Here, you no longer need to move the product over a scanner. Instead, the laser beams are continuously flipping backward and forward, channelled through an elaborate arrangement of mirrors and prisms. These ensure that the light reflects off the barcode regardless of the angle you’re holding it at.