Construction of a Low Cost Custom 2-D Bar Code Reader for Tube Racks

We describe the development of a custom system for reading 2-D DataMatrix bar codes imprinted on the base of tubes stored in a rack. The system software drives a standard flatbed scanner in order to acquire an image, interprets DataMatrix bar codes at predefined locations in the image, and returns in an array the interpreted bar code data along with other associated information. Commercial software components were used for the image acquisition and bar code interpretation portion of the software. An example is given that illustrates how to call the custom software from Microsoft® Excel and insert the returned data directly into a spreadsheet.