Research on soldering keyboard

I found a page about keyboard in wiki. Soldering is hard, very very small, but I think we can try it. The keyboard we have is very old. Maybe we can not press a lot of key at the same time. I found in keyboard, we can press 3 to 9 keys at the same time. I tried my laptop and 2 keyboard. But we have a lot of keys for our controller. We may have problem. Any suggestion?

I worry the old keyboard will only support to press 3 keys at the same time. And the keyboard is not ps2, we have to buy an adapter to try. Sometime I pass by my home, I see old computer with keyboard, if i found one, maybe we can use it.


Keyboard on Wiki