Jay Convertino Reverse Engineered the Classic ColecoVision to Create the Righteous Tentacle Clone

Engineer and vintage electronics enthusiast Jay Convertino has reverse engineered the classic ColecoVision games console — creating the Righteous Tentacle, a fully-compatible device which requires no cannibilization of existing consoles.

"This design is made so anyone can build [it]," Convertino writes of the permissively-licensed Righteous Tentacle console. "You may send it out to a fab house, you may use a PCB mill, or even etch it. This is possible since the components can serve as the plated through hole [via]. Other holes can simply have a solid piece of wire inserted and soldered to complete the connection (excess resistor leads is a great option)."

The original ColecoVision launched in 1982 as Coleco's — formerly the Connecticut Leather Company, and perhaps better known for its Cabbage Patch Kids the success of which saved it from the impact of the North American video games crash of 1983 — second-generation console. Known for having the first home version of Nintendo's Donkey Kong, the ColecoVision ran on an eight-bit Zilog Z80 processor with just 1kB of general and 16kB of video RAM plus cartridges storing up to 32kB of data.

Convertino's creation is a fully-compatible clone of the ColecoVision, using only readily-available parts — meaning there's no need to tear into an original ColecoVision to build the Righteous Tentacle. "Readily available," however, doesn't necessarily mean a current product: the Texas Instruments TMS9928 video display processor used in both consoles, for example, is long discontinued, but still in stock at supplies identified by Convertino for the project.

Cloned using a careful and considered reverse engineering of original hardware, the Righteous Tentacle is designed to fit into an original case or a 3D-printable case designed specifically for the project. Convertino has also designed 3D-printable ColecoVision-compatible controllers, for those starting from scratch — all of which is released under the permissive MIT license.

Full details on the project, including the KiCad project files and schematics, are available in the Righteous Tentacle GitHub repository and the project's wiki; the controller design is in a separate repository. Additional information is available in the project's Hackaday.io page.