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A printed circuit board (PCB),

GeoTronics LLC

We are Your Worldwide Open Source solution for fine Replicas.

Makers of the World-famous Open Enigma and Open DSKY!

S&T GeoTronics makes quality Open Source retro tech replicas.  It's what we do: combining our passions for history, technology, and engineering to bring you these unique products. We believe in craftsmanship, being intimately involved with the making of a piece of art that is well-made, long-lasting, and desirable.


An identifying factor of our craftsmanship is our interest in the process of creating. The focus is on the product, the creative process, and how much enjoyment it brings.  We are dedicated to Open Source, and you can make what we make by following our instructions.

These machines are assembled entirely by hand, by us, in our very small workshop. We have no "mass production" equipment. Each wooden case is made from 3/8" selected imported wood, and fitted with the best materials we can obtain. These cases will last as long as the electronics they contain. We look forward to doing business with you.


The S&T Geotronics Open Enigma

We brought you the Open Enigma

The S&T Geotronics Open DSKY

Then we released the Open DSKY

The S&T Geotronics Open Antikythera

We present you: Open Antikythera

A new master replica is coming Summer of 2023

  • Join us for an exploration through the old world

  • Help uncover an ancient technology & its untapped potential


Learn more

Open source logo


We are dedicated in providing you Open Source products and we invite the community to comment and collaborate.

Fine replicas


We take pride in everything we do: From recreating historical devices to providing vintage technology for the modern era.

Do it yourself


We are Makers at heart and we provide kits for all our products, or we offer fully assembled and tested units.



We take the time to assemble our units one by one in the sequence they are sold.

Arduino based


Arduino is aplatform we love and is at the center of both our Open Enigma and Open DSKY.

3D printed & laser engraved


We exclusively use the finest Prusa 3D printers in our print farm and have a number of high power CO2 Laser cutters/engravers.

James Sanderson and Marc Tessier


Marc Tessier
James Sanderson, VP

Marc Tessier

The "T" of S&T

Maker Pro with a passion for Arduino, electronics and 3D printing

"Un tien vaut mieux que deux tu l'auras!"

James Sanderson

The "S" of S&T

V.P. Alternative Engineering,

PCB Designer, Arduino Programmer,

3D Printer design creator

Name it, he can do it!

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