Once upon a time, far far away I was in working on my undergrad in a department that had a mix of equipment. They had a lab full of IBM PC clones running MS-DOS. These were mainly for the first couple years for Turbo Pascal work. What was really exciting was the senior lab of Sun workstations. I instantly fell in love with the Sun 3/60s. Even though they were no longer state of the art (SparcStations had recently come on the scene), they were still powerhouses for working with Lisp and Smalltalk.
Then it was off to grad school in a department that had mainly Sun workstations. And I was working mainly in Lisp and Smalltalk, so I found a used Sun 3/50 to have at home. I forget where I found it (this was long before eBay or Craig's List) but I got it at a good price.
I loved that computer. Ignoring speed, memory, etc. (68020 at 15 MHz with 4Mb of Ram [compare this to the 4GHz Core i7 with 64Gb that I'm using these days... hell compared with the Raspberry Pi that's sitting on my workbench: 1.2GHz 4-core ARM Cortex-A53 with 2G) it is one of the favorite computers I've ever owned. Part of that was SunOS (this was before Linux was generally available), part was X11, part was the huge screen (well, 21" was huge at the time), but a big part was the Sun Type-3 keyboard.
I've thought of getting one of these again ever since my ex made me get rid of workstation when I finished grad school. But there was the issue of it being a weird-ass serial interface that reports custom key scancodes and not USB. Well, fast forward to 2014 and I'm working at Steelseries where one of the things we make are keyboards. I got myself an ergodox and played around with the firmware. Bolstered by all that, I went looking on eBay and found a type-3 which I bought. The next step was to build a convertor to interface it with USB.
This eventually led me to the tmk_keyboard project, a keyboard firmware project for the Teensy which included a variety of convertors including one for Sun's type-5 keyboard. This provided me a good starting point. I had a Teensy 2.0 from the ergodox so I was good to go. Some researching, experimenting, and plain old hacking resulted in the Type-3 hooked up to my iMac via USB.
I forked the tmk repo and added a sun3_usb subproject/directory with my work.
The Teensy still needs to be moved inside the keyboard case and the coiled cable replaced with a USB cable. Once I get the right screwdriver. For now it works and I'm very happy with it.
The continuing story
I subsequently replaced the Teensy2 with a Teensy++, giving me more of everything, but especially more memory of the various sorts. I am planning to add programmable key bindings/macros.
The Teensy is now inside the keyboard case with a regular USB cable connecting it to the computer. I also added a reset button to the outside of the case to make it easy to upgrade the firmware.