Enigma machines were extremely interesting coding machines used by Germany during World War II. As digital logic was still in its infancy, these machines used rotors configured in a certain pattern to decode the gibberish sent from military commanders to units in the field. Although mechanical marvels, they came nowhere near being small enough to wear on one’s wrist.

Maybe even more amazing than the original is that this functionality can now be programmed into something the size of a (admittedly very large) wristwatch using an inexpensive Arduino processor. It looks quite nice, with a case made out of steel, and a strap made out of scrap leather.

As with the original machine, a sheet gives all the settings, which can be programmed in with the three buttons below the OLED display. The interface reminds me of setting up a GoPro camera, although three buttons is actually one more than a GoPro uses. The creator goes through setting up the watch, as well as a little bit of history behind it, in the video below.

[youtube https://www.youtube.com/watch?v=Lm7GEJFp6Bk]

If you’d be more interested in something that is a little closer in size to the original Enigma machine, although still electronic, S&T Geotronics has some interesting replicas to check out.

These are just a few of the pictures of his build. For complete details, check out the build log on his site.