Barcode or Barcode Reader is an optical machine-readable representation of data relating to the object to which it is attached. Originally barcodes systematically represented data by varying the widths and spacing of parallel lines, and may be referred to as linear or one-dimensional (1D). Later they evolved into rectangles, dots, hexagons and other geometric patterns in two dimensions (2D). Although 2D systems use a variety of symbols, they are generally referred to as barcodes as well. A barcode reader uses a photo sensor to convert the barcode into an electrical signal as it moves across a barcode. Mechanism: The scanner then measures the relative widths of the bars and spaces, translates the different patterns back into regular characters, and sends them on to a computer or portable terminal. If we use barcodes, we get online information without giving any data to the computer. If the manufacturing company produces large quantity of products, then these barcodes are very useful.