DIGI-COMP I - Introduction
DIGI-COMP I ("one") is a mechanical calculation device, delivered in kit form. Originally manufactured from polystyrene parts by E.S.R. Inc starting in 1963, it is as old as I am!
It was sold as an educational toy for just $4.99. Sales passed 100.000 and stopped in the 1970s with the rise of electronic toys.
There are many reference on the web, start with https://en.wikipedia.org/wiki/Digi-Comp_I and E.S.R.
DIGICOMP I is quite small: Dimensions are 31 cm x 8 cm x 12 cm. It consists of a mechanical 3 bit memory and programmable logic.
As an "electronic guy", I always was fascinated by mechnical calculation ... powered by a general lack of understanding. DIGICOMP came into my life after a speach about the arithmetic logic in Zuse Z1 (Klemens Krause on VCFB 2019).
Here it is running here (driven by a self-built motor), programmed to implement a binary counter:
This "binary counter" application as well as detailed functions are found in the user's manual, see attachement.
And: DIGI-COMP I is not to be confused with DIGI-COMP II ... that one is a nice looking marble calculator, but not programmable.
The Original Package
In Xmas 1963, you'd find DIGI-COMP I under your tree in this package (picture stolen from a recent eBay offer):
It came as a DIY kit, as a bunch of plastic parts.
You had to assemble all these before use, anticipating our IKEA experiences.
The user manual itself is a retro-futuristic gem and contributes greatly to DIGI-COMPs success.
Given the age of 1963, the rockets images are not yet inspired by the Saturn V moon-reacher .. .we're still in the Mercury aera here.
Community
In its prime time DIGICOMP had a big community, selected user games and problems were published by E.S.R. in add-on manuals.
Apparently there's still a fan group for DIGI-COMP and similar devices at Yahoo: "FriendsOfDigicomp". I wasn't able to find their message digest, but their file archive is here:
https://archive.org/details/digicomp_i/mode/2up
Some interesting documents are attached below.
Modern Implementions
DIGI-COMP is still fascinating people, there are several projects around it. I found these links to be active in 2020:
3D prints
DIGI-COMP I can easily reproduced on 3D printers, because all parts are plastic and flat. For example see this project:
Very important: Thanks to these guys, it's easy to replace a broken 1963 part with own prints. Long life DIGI-COMP!
DIGI-COMP I REDUX
This is another project for 3D printer, but a modified design:
https://www.instructables.com/id/Digi-Comp-I-Redux
Minds-On Toys Digi-Comp v2.0
This one is commercial. DIGI-COMP is made from card board instead of plastic.
http://mindsontoys.com/kits.htm?dc1_main.htm
Check out their site, lots of good info.
Online simulator
This is a web based simulator.
https://digicomp-1.appspot.com
You can develop own logic programs, and save and reload them later.
LEGO
Of course! http://www.nico71.fr/lego-computer-digicomp/
 coding-sheet.pdf | [DIGI-COMP I Coding Sheet as PDF Form] | 50 kB |
| DC1 Detailed Programming.PDF | [DIGI-COMP I Detailed Programming] | 3393 kB |
| DC1-PLA.pdf | [DIGI-COMP I as PLA (by friendsofdigicomp)] | 47 kB |
| digi-comp-1-instruction.pdf | [DIGI-COMP I User Manual] | 13713 kB |
| digi-comp-1-parts.pdf | [DIGI-COMP I Part List] | 1544 kB |
| digicomp-romps.pdf | [DIGI-COMP I Game And Problem Book] | 3561 kB |
| Duerig.PDF | [DIGI-COMP I Personal Narrative about Invention and Marketing (friendsofdigicomp)] | 817 kB |
| Patent_03273794.pdf | [DIGI-COMP I Patent Original (friendsofdigicomp)] | 1122 kB |