A barcode reader (or barcode scanner) is a computer peripheral for reading barcodes printed on various surfaces. Like a flatbed scanner, it generally consists of a light source, a lens and a photo conductor translating optical impulses into electrical ones. Additionally, nearly all barcode readers currently produced contain decoder circuitry analyzing the barcode's image data provided by the photo conductor and sending the barcode's content to the scanner's output port.

Types of Barcode reader
Many different types of barcode scanners are available. They can be distinguished as follows:

By light source

• LED scanners : also referred to as CCD scanners even though the CCD is in fact the photo imaging sensor, not the light source
• laser scanners : much more expensive than LED scanners but are generally capable of longer maximum scanning distances
• Imager scanners : These scanners take an image of the linear barcode, generally more rugged as they have no moving parts

By housing

• handheld scanner - with a handle and typically a trigger button for switching on the light source
• pen scanners (or wand scanners) - a pen-shaped scanner that is swiped across a barcode
• stationary scanners - wall- or table-mounted scanners that the barcode is passed under or beside. These are commonly found at the checkout counters of supermarkets and other retailers.