PC-Riter Mechanised Keyboard

A few years ago I saw this picture on the now-possibly-defunct ZZZ News site.

Although the machine shown here is a non-functional prop, it intrigued me greatly, and I decided to look into making a working typewriter-based pc keyboard.
I was able to borrow a Remington Travel-Riter Deluxe, which could be switched into a special "no advance" mode, where the keys would still clack and the hammers would still swing around as normal, but without the paper feed advancing, so I wouldn't have to worry about hitting the end of the line while typing.

Remington Travel-Riter Deluxe

Having selected my typewriter, I had to work out a way of connecting it to a PC. I took apart a succession of keyboards, testing out the circuit boards inside them to see how the various contacts corresponded to the keys. The first version of the circuit I built used a PS/2 connector, but I switched to a USB keyboard later on, as it was easier to connect and disconnect from my PC, and I could even use it at the same time as my normal keyboard.

Keyboard Controller Circuit

Not wanting to cut up a working and well-maintained typewriter, I decided to work on a special add-on that would sit under the typewriter, with small switches protruding up under the key levers. This would let the keys move normally, and when not being used with the PC, the typewriter can be lifted off and used to type on paper as usual.

Pushbutton Switches for Keys

By very careful placement of these switches, I could ensure that pressing the typewriter keys would activate the corresponding key on the PC. This placement was mostly down to trial-and-error, and proved to be the hardest part of the project. The finished base was connected to the typewriter and demonstrated for my Electronics Workshop class at university, where I was able to use it on the university Macs to type a few words for my classmates.

PC-Riter with Control Board