Using Tursi's PS/2 Interface as an enhanced joystick adapter?

[Omega-TI]

You know, it just occurred to me that one might be able to get an old PS/2 keyboard and cannibalize the internals to make an ENHANCED TI JOYSTICK. Since it appears that you'll be able to have both keyboards hooked up and working at the same time, the PS/2 adapter would even be a great item for people who just want to play games, not use an IBM style keyboard. One device, multiple applications.

 

All the keys are basically momentary switches, same as the joystick, so the arrow keys could be soldered to the stick, and then you could add additional buttons, for 1, 2 , 3 , BACK, REDO, SPACE, Q, or whatever you wanted. I'm just not sure how much of the keyboard could be cut away to fit in a smaller joystick case.

[Tursi]

While both keyboards can be attached and active at the same time, you can't /use/ them both at the same time. They're on the same scan matrix, so if a key is pressed on both at the same time, it won't work.

 

You could do the same without the PS/2 keyboard, but I guess the PS/2 port makes a convenient jack, was your thinking? The only other caveat that comes to mind is hot plugging won't (or shouldn't) work, you have to have the PS/2 plugged in when you power it up. For joysticks that's a little less convenient.

[Omega-TI]

Understood on the scan matrix. I have no problems plugging in before I turn on the computer though.

 

Yes, it makes a nice convenient, small and already existing port. Being able to have a multi-button controller for the TI would be a new evolution that might even spur new game development...of course that would require an easily available kit and not just a hack by one person.

 

The hardest part I think would be modifying the old PS/2 keyboard... unless it's modular and the decoder can be removed and is not integral with the keyboard.

 

I'd probably even leave an LED and add a button to turn off CAP LOCK!

 

 

The image below gives a 'visual idea' of what it might look like underneath. There are MAME kits available for the hardware, in our case we would just need the interface to connect the wires to.

 

[Tursi]

It's true, that would work, and then you could just use keyboard games as joystick games.

 

Thinking about current games I know about, I would probably start with Parsec and map ESDX to the joystick, then period as fire 1, Q and Y as 2 and 3, and 123 as buttons 4,5,6. Then you have your six buttons, compatibility with most games, and the Parsec Lift keys available to you.

 

Edit: although you have to make sure that the keyboard you've chosen lets you press combinations of those keys.

Edited March 6, 2015 by Tursi

[Tursi]

.. no.. actually, in retrospect... it won't work. The keyboard interface is designed to work as a keyboard, meaning that it expect you to press 1 key at a time (save modifiers). So it won't be able to tell the TI when you have two or more keys pressed at the same time.

 

That's not impossible to do, just something I didn't consider. It'd be a rewrite of the firmware.

[Omega-TI]

Okay, thank's for the heads up on that. I suspected something was amiss when I tried playing Pole Position with the keys that do work. It's nice to get verification from the creator. I guess I'll not be sourcing those parts after all.

 

After I get it fixed on the 14th, and get the TI's WiFi issue squared away, my TI will be in need of a new project or toy until the new controller card becomes available... and for the first time I have no idea what that could be.

[Tursi]

hehe.. sorry. I tested the game playing aspect with Munchman, I didn't think about multiple keys at the same time.