© 2000 Jamie Zawinski <firstname.lastname@example.org>
I've had this idea for a cool project to build for a few years now, and it's looking like I may never get around to actually building it, so I thought I'd just write about it instead, and maybe someone else will. Because the world needs one of these.
The idea is this: rig up an ancient manual typewriter to function as a computer keyboard (thereby making a lie out of the standard Unix error message, ``ENOTTY: not a typewriter.'')
As you probably remember (or not, since if you were born in the 70s you probably never had to use one of these things) the mechanism is that when a key goes down (hard and far!) it causes a long, thin metal bar to pivot forward and smack the paper, which is threaded through the machine on a roller.
The basic idea would be to use the impact of each rod's print head with the roller as the electrical contact. The connection of each bar to its pivot point would need to be electrically isolated; each of them would be charged, and the roller rod would be the electrical return (by coating the roller with something conductive.) Then all you need is a little bit of circuitry that would note the completion of 50 or so different circuits, and send corresponding codes out a serial port.
Handling shift is a little trickier, since the way the shift key works is by changing the angle at which the print heads strike the paper. To do this, a microswitch would probably have to be embedded inside the mechanism somewhere.
Anyway, I think that making use of contact with the roller is a much cooler way to go about this than just putting a sensor beneath each key. It's a better hack, because it functions much more similarly to the way the original mechanism worked.
This also might let us find out whether there's any truth to the rumor that manual typewriters are better for your wrists than computer keyboards.
Then all you'd need was an 8" monitor with a 27" fresnel lens in front of it, and you'd be set.
A somewhat similar idea I had was to find an old Bell System
telephone, the big black rotary phone that
was the only kind of phone that existed back before the telco breakup,
and install a cell phone inside it. Sure, it'd
be a little bulky, but it would be a rotary phone that didn't have a
wire coming out of it, and that worked anyway. And you could put a
huge battery in the thing...
Update, 2002: Someone went and built the typewriter! ``ElectriClerk: A 1988 MacSE with a 1923 Underwood typewriter for its keyboard.'' I doubt I was the inspiration, but still, I'm glad it happened, because it was a moral imperative. Sadly, he didn't give many details on how it works.
Update, 2003: Here's another! `` The Typewriter-Keyboard Conversion.'' This one has detailed photos of the construction process, and even the carriage-return handle works. (The only major drawbacks seem to be the lack of Backspace, Control, or Alt keys.)
Update, 2003 #2: Here's a cellphone inside of a desktop phone. It's a pushbutton phone, not a rotary dial, so that only gets partial credit.
Update, 2004: Here's an entire PC stuffed inside a typewriter: The Underwood No. 5. He didn't rig up the original keys, but instead just glued the old keycaps to a regular computer keyboard.
Update, 2005: Here's another cellphone inside of a desktop phone. This one rules, because it has a rotary dial! However, they say that incoming calls don't ring, and the sound quality is not as good as it should be.