Bar codes: The little symbol that could

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 Electronic Cash Register and Scanner Manufacturer Centralized Computer EID Store’s Centralized Computer

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

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

Universal Product Code: Main Features Source: (http://www.barcodeart.com/science/science.html)

Universal Product Code: Main Features Module Interpretation Number Systems Chars U.P.C. Digits Source: (Brown 282, 287) and (http://electronics.howstuffworks.com/upc1.htm)

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..) • 6+9+8+0+0+9 = 32 • Multiply this by 3 • 32*3 = 96 • Sum even digits (2, 4, 6..) • 3+3+2+0+3 = 11 • Add this to value in Step 2 • 96+11 = 107 • Determine then number that added to the above value would generate a multiple of 10 • 107 + 3 = 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 PDF417 • 2D bar codes build on existing technology • Stacks • Matrices • Check words • Fun applications • p8t.ch website – 2D patches that when scanned links to URL Stacked Matrix Source: (http://www.barcodeman.com/faq/2d.php)

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: (http://www.howstuffworks.com/rfid.htm)

The Future?

Bar codes: The little symbol that could