In the 1960s, computers could take up an entire room. While engineers generally did calculations on slide rules and paper, you could actually get a digital calculator in the form of the Wang 300. Unlike calculators of today, or even the more recent past, these devices consisted of a dumb terminal — reminiscent of a 1980s-era adding machine — and an external Electronic Package, as Wang called it. The user would type inputs into the terminal, the larger Electronic Package would do calculations, and send it back to be displayed in glorious Nixie characters.
Bob Alexander purchased one of these consoles, “complete” with the electronics cable cut off, but the Electronic Package needed to get it functional can sell for ~$2,000 when they’re even available, and are often broken. They need three different voltage levels (-11, 0, and +11V) to operate, so actually repairing one can be a challenge. Alexander instead decided to design his own “Electronic Package” using a modern circuit board with a PIC32 microcontroller that fits inside of the space in the console’s enclosure. It plugs in to the unit’s internal cable socket, meaning no original hardware is destroyed in the process.
His device functions not only as a Wang-style calculator, but can operate in reverse Polish notation (RPN), and features a keypad test application as well as a configuration screen. Last but not least, when the calculator is turned off but plugged in, it displays the time and date in glowing Nixie light. Time is kept with a GPS module, so he doesn’t have to worry about setting it, though display format, time zone, and daylight savings time rules can all be configured as needed. More info can be found in Alexander’s write-up, and he gives a more detailed explanation of the project in the video below.