Bar codes: The little symbol that

couldNikki 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: (http://www.barcodeart.com/science/science.html)

Universal Product Code: Main Features

Source: (Brown 282, 287) and (http://electronics.howstuffworks.com/upc1.htm)

Module Interpretation

Number 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..) 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

2D bar codes build on existing technology Stacks Matrices Check words Fun applications

p8t.ch website – 2D patches that when scanned links to URL

Source: (http://www.barcodeman.com/faq/2d.php)

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

The Future?