Topic of the Day - Bar Codes

The first step toward today's bar codes came in 1948, when Bernard Silver, a graduate student, overheard a conversation in the halls of Philadelphia's Drexel Institute of Technology. The president of a food chain was pleading with one of the deans to undertake research on capturing product information automatically at checkout. The dean turned down the request, but Bob Silver mentioned the conversation to his friend Norman Joseph Woodland, a twenty seven year old graduate student and teacher at Drexel. The problem fascinated Woodland.

Woodland remembers starting with Morse code, "I just extended the dots and dashes downwards and made narrow lines and wide lines out of them." To read the data, he made use of Lee de Forest's movie sound system from the 1920's. De Forest had printed a pattern with varying degrees of transparency on the edge of the film, then shined a light through it as the picture ran. A sensitive tube on the other side translated the shifts in brightness into electric waveforms, which were in turn converted to sound by loudspeakers. Woodland planned to adapt this system by reflecting light off his wide and narrow lines and using a similar tube to interpret the results.

Not until the 1960s were two technological developments available to make scanners simple and affordable: cheap lasers and the integrated circuit. When Woodland and Silver first came up with their idea, they would have needed a wall full of switches and relays to handle the information a scanner picked up by a microchip.

On June 26, 1974, all the tests were done, all the proposals were complete, all the standards were set, and at a Marsh supermarket in Troy, Ohio, a 10-pack of Wrigley's Juicy Fruit chewing gum became the first retail product sold with the help of a scanner. Today, the pack of gum is on display at the Smithsonian Institution's National Museum of American History.