This keyboard is something I acquired last year in a collection of items and was a "throw in". To me, it's one of my most treasured items because of it's home-made construction. To be honest, I don't know what the keyboard mechanism is at this point but I'll take some more pics in the next day or two.
Look at this construction!
After assuming it was a simple home-made parallel or serial keyboard in it's era, some research indicated it's actually more than a keyboard. Along with the keyboard is an internal computer board from a Diablo paper-based terminal (before CRT) that was smart. Internally, it has an Intel 8080 CPU that was the same used as the central processing unit in most computers of the time (including the Altair 8800 and the IMSAI 8080).
If you look carefully, you can see the keyboard from the paper-based terminal pictured below with more information on the Diablo terminal here: http://www.columbia.edu/cu/computinghistory/diablo.html

As mentioned, I'll take some more pictures and clean it up in the next couple of days. I guess it would be difficult to guess what the keyboard is? At the time, I didn't care about keyboard specifics so it will be a surprise (or disappointment) to me too

Hope you enjoy.