Post on 22-Jan-2016
description
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?