When you discover you can eventually figure out most anything, you know, like, "I can replace the transmission in my car," you start going down serious rabbit holes.

I like rabbit holes. The problem is that though you can do most anything, it's still often difficult to actually pull something tangible off. For instance, it seems pretty easy to make an audio cassette player. Schematics are out there. And I bet with a good enough motor, you wouldn't need a flywheel to regulate play speed. You certainly learn some cool stuff -- exhibit analog computers, for instance, was something my cassette player rabbit hole turned up as part of an intermediate cMoy amplifier rabbit hole.

But there's often still a barrier to true productivity after the euphoria of researching a new topic that's probably a bit too high to easily deliver concrete results without enlisting some "real" expert help.

(This is also the difference between replacing a transmission, which I've pulled of a few times, and an engine, where I think I 90% succeeded, but still took to a shop to finally get the installation debugged & fired up.)

Anyhow, my latest rabbit hole has been custom keyboards, and it's one where I think any reasonable schmoe can achieve productive, concrete results. I mean, it's a very popular geek pastime, and the domain is pretty straightforward.

1. Put power into a circuit full of switches
2. Detect when switches close (aka, power goes through them)
3. Communicate those closures with a listener.

Apparently PS/2 is super simple, but we've still been using microprocessors to read the circuits for some time. From wikipedia.org:

The first computer keyboards were for mainframe computer data terminals and used discrete electronic parts. The first keyboard microprocessor was introduced in 1972 by General Instruments, but keyboards have been using the single-chip 8048 microcontroller variant since it became available in 1978.^[41] The keyboard switch matrix is wired to its inputs, it converts the keystrokes to key codes, and, for a detached keyboard, sends the codes down a serial cable (the keyboard cord) to the main processor on the computer motherboard

So on its face, a very simple proposition, repeated a number of times, and you've got a keyboard, which we always knew in theory was just a lot of buttons each like the battery-powered buzzers we might have played with years ago, but there's nothing like studying the innards for that to really, practically make sense.

Anyhow, that's too much preamble. I'm not writing a book. Here, in good web-log style, are some good links to information about keyboards that I've run into during the rabbit hole exploration...

(Warning, like other giant log dumps, this post wasn't proofread even as well as my typical post, which is pretty bad...)

Labels: DIY, keyboard