Crystal Hammer

⏱️Overview

This is an older topic with less information, just for history purpose. If you’re interested see my newer keyboards or the newest ones, with more explanation, own controller and display.

These were my first modifications for keyboards.

They were both done on a Logitech Ultra X Flat, a well done, solid keyboard. Surprisingly different for same model made after 1 year.

✍️Motivation

Originally most keyboards have about 50 gram force needed to press keys, and probably 4 mm distance. After first step of cutting rubber domes the distance is about 1-2mm, the force was about 22 gram for CK1 (bottom) and 33g for CK2 (top). This can also be varied per key.

📊Features

The second step was removing the middle part with arrows. Which I find unnecessary and worse (less keys) than the same from numpad. In CK1 I’ve bent the foil and hid it under. It was risky, but the foil survived. The CK2 was different, it was made from two identical keyboards, thus no need to bend, only cut the metal and foil. That too was risky since the foil could have connections around the cut off part. It was only for numpad, the bigger part had whole foil under.

Years later I modified CK2 further and bent the foil to create CK4 keyboard. And that’s 11 years already, so this would answer any doubts for longevity of such modifications. The number of times I disassembled it, changed something, and put it together is also quite high.

The third step was adding extra keys. Using my oldest program for showing pressed keys and their codes, I figured out that there are more possible keys in keyboard matrix, that are just not connected. So I added them with wires and glued on keyboards. First as regular switches with metal domes, small and hard to press. Later using rubber switches, lighter to press. But turned out to be an even bigger fail since they wear out and stop connecting. They have some resistance too (like maybe 300 ohm) in addition to the resistance of foil traces (maybe 150 ohm). So finally I ended with the smallest metal dome switch I found, with force 0.5 N (50gf). It feels different than other keys but otherwise is good.

📷Galleries

The old galleries from my keyboards:

1. CK2 final (2008)
2. CK1 and 2 making of (2005 and 2006)

Most pictures have some description text (explaining what I did there).