reader is an optical input device, which is used to read the values or quantities printed on the products in the form of vertical bars known as bar code. Bar code is recorded on the product by the manufacturers and usually carries the inventory stock number or unique product number. The coding scheme called Universal Product Code (UPC) for recording the data is based on the width of the bars and
the space between them. The bar code reader uses a laser beam to read and interpret bar code. The reader emits a laser beam that reflects on the bar code. The bar code reader consists of a light sensitive detector that identifies the bar code image and converts it into a numeric code that can be processed further.