Bar codes: The little symbol that could Nikki Candelore Discrete Math: Summer ’08 Professor Langston

What is a bar code?

What we take for granted Store’s Centralized Computer Electronic Cash Register and Scanner Manufacturer Centralized Computer EID

U.P.C: Younger than you’d think 1930s – Harvard punch cards 1950s – Drexel blanks and bars 1970s catalysts  1974, Wrigley’s gum in Troy Ohio  Rising inflation and impact of labor grocery profitability  Deux ex machina – 1973 FDA regulation change on labeling provides real impetus for change  Consumer outrage at prices being removed 1990s – take off

Source: (Brown 4) U.P.C: Younger than you’d think

Universal Product Code: Main Features Source: (

Universal Product Code: Main Features Source: (Brown 282, 287) and ( Module InterpretationNumber Systems Chars U.P.C. Digits

Universal Product Code: Built in Checks Inverted bars after middle guard bar Splotches Check Digit Calculation  Sum odd digits (1, 3, 5..)  Multiply this by 3  Sum even digits (2, 4, 6..)  Add this to value in Step 2  Determine then number that added to the above value would generate a multiple of 10

Universal Product Code: Built in Checks Check Digit Calculation: Example  Sum odd digits (1, 3, 5..) = 32  Multiply this by 3 32*3 = 96  Sum even digits (2, 4, 6..) = 11  Add this to value in Step = 107  Determine then number that added to the above value would generate a multiple of = 110 Therefore 3 is our Check Digit

Other types of Bar Codes U.P.C. symbol Code 39 Interleaved Two of Five Source: (Gieco 30)

Code 2 of 5 and Interleaved 2 of 5 Source: (Baker 21)

Code 39 Source: (Baker 21)

The Future: 2D bar codes 2D bar codes build on existing technology  Stacks  Matrices  Check words  Fun applications p8t.ch website – 2D patches that when scanned links to URL p8t.ch Source: ( PDF417 Stacked Matrix

The Future: Radio Frequency Identification Electronic device uses radio frequencies to communicate No need for line of sight Holds more information than a bar code Can be read from or written to Security issues remain a concern, particularly for consumers Source: (

The Future?