Bar code scanners detect the black lines on a bar code.
Bar codes are common identification symbols for items such as products for sale, shipping cartons and blood donations. A bar code scanner translates the lines in a bar code into numbers, which correspond to specific items or products.
History
Norman Joseph Woodland and Bernard Silver patented the bar code on October 20, 1949. Bar codes became common for products in the 1970s. In 1974, Marsh's supermarket in Troy, Ohio, became the first grocery store with a bar code scanner.
Mechanics
Bar code scanners contain a row of light-emitting diodes. When the light from the bar code scanner hits the bar code, the scanner can sense which areas are light and which are dark. It translates the bar code into a string of binary: 0 for the light areas and 1 for the dark areas.
Translation
The bar code scanner's software translates the binary code into a number. A human reader can read this number from the bottom of the bar code. Scanning the bar code's lines, however, makes it easier to keep track of items than punching in a long numerical code.
Tags: code scanner, code into, code scanners, lines code
