Digi-Comp II Replica

thingiverse

Digi-Comp II, a mechanical computer designed by John Thomas Godfrey and produced by Education Science Research (E.S.R., Inc.), was invented in the late 1960s. As seen in the accompanying images, the device consists of a frame approximately 14 inches wide and 28 inches long, positioned at an angle for optimal performance. Calculations are performed through balls rolling down channels on top and within the platform, guided by gates that redirect the ball's path or alter its state. Originally intended as an educational tool to teach computer concepts, Digi-Comp II can count, perform basic arithmetic operations, and calculate either the 1's or 2's complement of a number. The device operates in two modes: auto mode, where the balls are released automatically after each step until the operation is complete; and manual mode, where the user initiates each step. For those interested in learning more about Digi-Comp II, several excellent online resources are available. These include: * Wikipedia: [Digi-Comp II](https://en.wikipedia.org/wiki/Digi-Comp_II) * Old Computer Museum: [Digi-Comp 2](http://www.oldcomputermuseum.com/digicomp_2.html) Additionally, a video showcasing an original Digi-Comp II in operation can be viewed below: <iframe width="560" height="315" src="https://www.youtube.com/embed/O9zb964J0VA" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> While the Digi-Comp II is not fully programmable, an earlier model by E.S.R., the Digi-Comp I, utilized plastic slides, tubes, and bent metal wires to solve simple logic problems. Mark Ziemer created a highly detailed replica of this device. He also developed a virtual application for the Digi-Comp II. For those interested in creating their own Digi-Comp II from scratch, a full-size working replica is available as an STL file and assembly instructions. This project includes a PDF manual that came with the original device, which was spiral-bound by a local copy center. The offering is designed to be as authentic as possible based on images and technologies available. The original top and inside decks were made from vacuformed plastic attached to masonite boards, while flip-flops and switches were injection molded. In this replica, the decks and pieces are 3D printed.