Commodore CHESSmate Replica Runs On The ESP32

The Commodore CHESSmate chess computer might not be terribly well known, but that doesn’t make it any less worthy of being reproduced. If anything it is more important, as it gives more people an opportunity to use one of these devices, yet beyond a purely emulated experience the real user interface is harder to experience.

Internals of the reproduction Commodore ChessMate (Credit: Michael Gardi)

This is where [Michael Gardi]’s modernized replica provides a highly accessible version, consisting of a custom PCB with an ESP32 as the brains of the system. Although decidedly overkill next to the 6502 in the original CHESSmate, it makes the project far easier for others to assemble as it contains few components that shouldn’t be readily available.

The ESP32 is mounted on a small daughterboard which plugs into the main PCB with the buttons, LEDs and indicators. The whole stack is then inserted into the 3D printed reproduction case. These 3D models along with the ESP32 port of the CHESSmate firmware can be found in the GitHub repository, along with a minimalist frame and a ‘CHESSmate Lite’ version as alternative enclosure options for those who somehow don’t appreciate the delightful 1980s aesthetics.

We covered the Commodore CHESSmate last year, including a highly faithful reproduction built by [Hans Otten], which [Michael] read the day after meeting [Peter Jennings], the author of MicroChess (which the CHESSmate uses internally) at an event at York University. Taking this as a sign, he set to work on this particular project.

We’re not sure if there’s really a cosmic force directing [Michael] towards his next project, but if there is, we’d like to take this opportunity to thank it for doing a fantastic job so far.

The Quaint History Of The Commodore ChessMate

The Commodore International of the 1970s was a company which dabbled in a bit of everything when it came to consumer electronics, with the Commodore ChessMate being a prime example of the circuitous way that some of its products came to be. Released in 1978, its existence was essentially the result of MOS Technology releasing the KIM-1 single board computer in 1976. In May of that year, [Peter Jennings] traveled all the way from Toronto, Canada to Cleveland, USA to attend the Midwest Regional Computer Conference and acquire a KIM-1 system and box of manuals for a mere $245. On this KIM-1 he’d proceed to develop his own chess game, called MicroChess, implemented fully in 6502 ASM to fit within the 1 kB of RAM.

As one of the first major applications to run on the KIM-1, it quickly became an international hit, which caught the attention of Commodore – which had acquired MOS Technology by then – who ended up contacting [Peter] about a potential chess computer project. This turned out to based on the custom MOS 6504 CPU, while sharing many characteristics with the KIM-1 SBC. Being a MicroChess-only system, the user experience was optimized for more casual users, with the user manual providing clear instructions on how to start a new game and how to enter the position of a newly moved piece, along with no less than eight difficulty settings.

If you’re feeling like making your own ChessMate, or want to dig into the technical details, this excellent article by [Hans Otten] has got you covered.

Top image: Commodore ChessMate Prototype in 1978. (Credit: Peter Jennings)

(Thanks to [Stephen Walters] for the tip)