The Supermarket Scanner Changed the Way We Buy Groceries Forever

Invented 50 years ago, the curious box deciphered an arcane kind of code to offer shoppers a trip into the future

A Spectra Physics Model A supermarket scanner—one of the first ten ever produced. A laser within the unit projects a beam onto a mirror that redirects it through the glass plate on the top.
A Spectra Physics Model A supermarket scanner—one of the first ten ever produced. A laser within the unit projects a beam onto a mirror that redirects it through the glass plate on the top. Cade Martin and POP Creative

On the morning of June 26, 1974, an unremarkable pack of chewing gum in Ohio made history.

At the Marsh Supermarket in Troy, as in major grocers throughout the country, cashiers would ring up items by manually entering the price of each on a cash register before computing a final tally. That day, though, saw something new: An employee named Sharon Buchanan rang up a packet of Wrigley’s Juicy Fruit chewing gum without ever having to key in a price. Instead, she used a remarkable new gadget to scan a symbol on the packaging that would indicate the cost. The bulky rectangular device—visible to the customer only as a silver plate with four light sensors—was one of the store’s ten brand-new Spectra-Physics Model A’s. The unglamorous name suited its unexciting veneer, but for customers and cashiers alike, it would change shopping forever, making checkout a piece of cake.

Clyde Dawson, the shopper who purchased that fateful pack of gum from Buchanan, was also Marsh’s head of development and research. Along with executives at grocery stores across the country, Marsh had been preparing for this big day since 1970, when the grocery industry began to study the possibilities of introducing bar code scanning into stores.

Though some shoppers and grocer’s clerks were skeptical about the new tech—a few customers missed the old hand-placed price tags on each product—the checkout process itself was undeniably smoother. Speaking to the Troy Daily News, the store manager at Marsh’s declared a victory for all shoppers: “This system will eliminate cashier error, and it also ensures the customer that she is getting the full advantage of price breaks on items which are sold in multiples.”

The debut of the price scanner was also good news for the bar code, a world-shifting idea that had been languishing since its invention in 1949. The brainchild of Norman
Joseph Woodland and Bernard “Bob” Silver, both engineering graduates of Philadelphia’s Drexel Institute of Technology, the bar code was formulated from elongating Morse code’s vocabulary of dots and dashes, creating a system inspired by Woodland’s deep love of Morse as a Boy Scout.

Finally, with the arrival of the microcomputer and the creation of laser scanner technology in the early 1970s, the National Cash Register Company and Spectra-Physics, Inc.—the latter of which had been making commercial industry lasers since 1962—collaborated to produce the game-changing scanner known as the Spectra-Physics Model A. The scanner projected light onto a given item’s barcode. In no time at all, the machine’s photo-diodes then translated the reflected light and directed the deciphered data to an in-store computer, which matched the incoming signal with a product description and price. The slick contraption could decipher a code so small that it could be printed on a pack of chewing gum.

According to Hal Wallace, curator of electricity collections at the Smithsonian’s National Museum of American History, each scanner was cumbersome and cost Marsh $4,000, or around $25,000 today, plus expenses for installation and training. Despite the daunting weight of the steel-encased machine—its contents included chips and capacitors and copper transformers—mostly, Wallace says, it contained air. The main business happened in reflections and refractions of light. Marking the dawn of what we now refer to as “frictionless” technology, the scanner’s design immediately declared its glittering modernity. Where much of 19th-century technology tended not to hide its cogs and wheels, most operations of a supermarket scanner take place out of sight. “It’s designed to be an invisible technology,” Wallace says.

This 1974 scanner rests out of view in the National Museum of American History’s electronic collection. But its descendants are all around us—foremost in the ubiquitous self-checkout register—all thanks to the revolution that began 50 years ago, when Sharon Buchanan swiped Clyde Dawson’s gum.

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This article is a selection from the June 2024 issue of Smithsonian magazine

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