RetroDisks' WiRSa Is a Clever Wi-Fi Modem for Vintage Computers, Originally Built to Drive Props

Vintage computing accessory specialist RetroDisks has launched a new, open-hardware communications tool for classic computers: the WiRSa Wi-Fi RS232 Serial Modem, boasting an on-board microSD slot for expanded storage and a feature designed for TV set-dressing.

"With a capable terminal software on the target computer," RetroDisks' pseudonymous "nullvalue0" explains, "you can transfer binary files directly from the SD card. YModem transfer protocol currently test[ed]/working with others coming soon. [It also has] text display/playback which can read file from the SD card and send them out across the serial line for display on your computer or terminal."

The story of the modem's origin, and its unusual text-typing feature, is an interesting one. "This began as a device I built for the filming of Apple TV's 'The Shining Girls,'" nullvalue0 says. "There were a number of scenes involving computer terminals. They had the terminals but no idea how to display anything on them.

"I came up with this device as a means to display a static block of text at the terminal or 'playback' a text file — i.e. when the actor hits a key on the keyboard, regardless of what key is pressed, the next character from the text file gets printed. This creates the illusion that the actor is actually typing the document in real-time but they're really just mashing keys. I've included this text playback feature in the firmware."

A the heart of the modem is an Espressif ESP8266 microcontroller, which is running a custom firmware based on the earlier WiFi SIXFOUR Commodore 64 modem project — itself building on Jussi Salin's Virtual Modem for ESP8266. The RetroDisks version communicates with a host over RS232 via a RB9 connector, with a micro-USB connector for power. An optional 3D-printed case provides some protection against mishandling.

The RetroDisks WiRSa is now available on the company's Tindie store starting at $24.99 for a do-it-yourself kit version, with the 3D-printed case adding $5 on top; design files and source code are published under the permissive MIT license on GitHub.