Emulating a pinwheel calculator

The Odhner Arithmometer – a pinwheel calculator – was invented in Russia in 1873 by a Swedish immigrant named W. T. Odhner.

Photo Credit: Wikipedia (Ezrdr)

According to Wikipedia, pinwheel calculators were typically powered by a set of wheels with an adjustable number of teeth (“pinwheels”) that could be set via a side lever to expose anywhere from 0 to 9 teeth.

When coupled to a counter they could, at each rotation, add a number from 0 to 9 to the result. By linking these wheels with carry mechanisms a new kind of calculator engine was invented. Turn the wheels one way and one performs an addition, the other way a subtraction.

Photo Credit: Wikipedia

Industrial production of Odhner’s Arithmometer officially kicked off in 1890, lasting 30 years until Odhner’s St. Petersburg factory was nationalized and shuttered during the 1917 Russian Revolution. However, a number of independent companies had already been established all over the globe to manufacture Odhner clones. By the 1960’s, Odhner’s Arithmometer had become one of the most successful mechanical calculators ever designed, with variants including the Thales, Triumphator, Walther, Brunsviga, Britannic, Muldivo, Multo, Original Odhner, Felix, Tiger and Busicom.

Fast forward to late 2013, when a Maker by the name of Diego Cueva used a versatile Atmel-based Arduino Uno (ATmega328) to create an Arithmometer emulator aptly dubbed the Duimometer (Arithmometer + Arduino).

The video above definitely speaks for itself (with subtitles) and we are suitably impressed. However, we can’t help but wonder what W. T. Odhner himself would think of the project. While we’ll obviously never know for certain, it’s probably safe to say that he would be giving Cueva loud props and applause for his efforts.

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