Cut down keyboard

This is a very old article. It applies to very old AT style keyboards, which pretty much don't exist anymore. However, it might still be useful to some people.

What the ...?

Sometimes, a big, fullsize keyboard is a hassel. And sometimes, a custom keyboard made from little buttons and connected to a parallel port is a hassel. And sometimes using a microcontroller is a hassel, too.

And those small, custom keyboards cost so much, too!

What I wanted was a small keyboard, to control a fileserver of mine. I wanted something that was easy to interface and program with. The easiest thing to program with is, naturally, a keyboard.

So, I made a small keyboard. I knew what I wanted to keep, so I mapped that out. A friend and I made a day of it to make two keyboards from three others.

We started with three keyboards. Disassembling these revealed one keyboard that was made from buttons soldered onto a PCB. The other two contained a small controller board and then a thin plastic matrix thing. So, we took the buttons from the PCB keyboard (because the controller components were all over the board, making it rather difficult to cut down), and took the controllers from the plastic matrix keyboards.

Before we completely disassembled the plastic matrix keyboards, we mapped out what keys connected to what pins, on paper. We then got a piece of veroboard (a PCB with lots of holes, and tracks running along one dimension) and soldered all the keys we wanted, in the fashion that we wanted.

After that came the fun part... attaching it to the controllers. Some nice hookup wire was used for this... and after some mucking around, we had ourselves two little keypads.

Powering up the keypads resulted in a partial failure. Some keys worked, and some didn't. After some checking against the drawings we made, we found that some connections were wrong. But, never fear, a few touches with the soldering iron and we corrected those errors.

Pictures of the result

Here are some pictures of the final result. I only have pictures of the little keypad I kept, and not the other one. Also, I don't have any "during" pictures, because we didn't take any. All I can show is the final result.

The Keypad from an angle (33,708 bytes)
The finished keypad

Top view of keypad (41,526 bytes)
A top view of the keypad.

Connecting the keys to the controller (38,905 bytes)
This shows how I connected the keys to the board.

The ZiLOG Z0860204 Keyboard controller (39,172 bytes)
Look! Zilog made the controller!

Building your own

So you want to build one too? Well, here's a few hints...

But other than that, have fun. If you make one, send me some pictures - I'd be interested to see what others did with theirs...