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Nothing New Under The Sun

May 28, 2010

When I was a small child, I was confronted with my first paradox. My father was a carpenter, so there were many tools around the house, especially hammers. As I was contemplating a hammer, it seemed to me that you needed a hammer to make a hammer, so how could a hammer exist? It was only later that I realized that there's a hierarchy of hammers. You have stones, and these can be used to chip other stones into shape to make nice stone axes, and so on. Now, there are special purpose hammers (including the one used in an attempt to repair a television camera during the Apollo 12 lunar mission), but all these are variations on a stone and improvements of previous hammers. Most inventions are just variants of something else. Of course, they must be novel variants or they wouldn't pass muster at the patent office. [1] It comes as no surprise that the ubiquitous automated teller machine (ATM) was modeled after a candy vending machine.

John Shepherd-Barron, inventor of the ATM, died on May 15, 2010 at age 84. The ATM machine is surely one of the most successful inventions of all time, since there are now 1.8 million networked ATMs worldwide [2]. Shepherd-Barron's motivation for his invention came when he arrived too late at his bank to cash a check. Fortunately, a local garage cashed his check, instead, but the incident got him thinking. In an interview with the BBC on the fortieth anniversary of his invention [3], Shepherd-Barron said,

"That night I started thinking that there must be a better way to get cash when I wanted it. I thought of the chocolate vending machine where money was put in a lot and a bar dispatched. Surely money could be dispensed the same way."

Shepherd-Barron pitched his idea to Barclays Bank, and within a matter of weeks he was given a contract for six prototype units [4]. The original ATM, called a Barclaycash Machine dispensed just £10 (about $100 in today's money), and it was dedicated on June 27, 1967 [2]. Of course, 1960s bankers had their own typists and telephone receptionists, so they weren't accustomed to pushing buttons. Shepherd-Barron had to teach a Barclays vice chairman to push the buttons to enter his PIN number [2]. Shepherd-Barron's wife insisted that a five-digit PIN number would be too difficult to remember, so PIN numbers were standardized at just four digits. [2]

The ATM Card wasn't invented simultaneously with the ATM. In this early machine, a customer would insert a paper check, instead. Aside from a match to the PIN number, the checks had a trace of radioactive carbon-14 as a security feature. [4] The radioactive tracer was considered safe enough at the time (Shepherd-Barron calculated that you would need to eat 136,000 checks to to get a clinical dosage), but I'm certain that a product like that could never be marketed today.

Since the ATM machine was a work made for hire, Shepherd-Barron didn't make a fortune from his invention, but he was named to the Order of the British Empire in 2004, thereafter being called Sir John.


  1. Wikipedia, "Inventive step and non-obviousness."
  2. Stephen Miller, "A Sweet Inspiration For Cash Dispensers," Wall Street Journal Online (May 21, 2010).
  3. Julia Werdigier, "Obituary: John Shepherd-Barron / Scotsman credited with inventing the ATM," The New York Times Online (May 22, 2010).
  4. "John Shepherd-Barron," Telegraph (UK, May 20, 2010).

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