Like all good stories, this one starts with a fantastic vintage find at a local electronics flea market. Imgurian Iafan was perusing the wares when he came across a Beckman Model 421 dumb terminal from the early ’80s, which was designed to work with Beckman’s range of chromatography lab equipment. It didn’t have any logic, and was broken anyway, so Iafan set out to convert it into a Raspberry Pi computer.
The Beckman Model 421 was essentially just a CRT display with a small keyboard attached. It couldn’t do any processing of it’s own, and was really only intended to be an interface for other equipment. The display wasn’t functional, likely due to a bad driver board, so Iafan’s first step was to replace it with a 10.4″ 640×480 Sharp LCD panel that was salvaged from an old digital photo frame. That was mounted on PCB blanks to keep it in position within the Model 421 housing, and a VGA input was hacked together.
The display receives a video feed from a Raspberry Pi through an HDMI-to-VGA adapter, with the addition of a VGA scanline generator designed to replicate the look of a CRT. The Model 421 didn’t have a QWERTY keyboard, and instead had dedicated keys for lab equipment functions. So, Iafan had to get creative. Using an Arduino Pro Micro to turn the keyboard into a USB HID, he programmed a complex set of layers that takes the small number of keys and dynamically remaps them as necessary.
The result is a fully-functional Raspberry Pi computer inside of a beautiful vintage case. Iafan has RetroPie install for retro gaming, but says he mostly uses the machine to listen to internet radio with MPD. Frankly, it doesn’t matter what he does with it, it will look awesome regardless.