JOY81 - Programmable Joystick Interface for ZX81

[siggi]

Hi Kelly,
of course the Inkey$ and INPUT routines can only detect valid keys. But, as I wrote, scanning the keyboard directly by using IN/OUT, a m/c program can detect multiple keys being pressed. E. g. there are games, which accept all keys connected to a keyboard column as one key and another column as second key.
And I also once wrote a BASIC(!) program, which could detect multiple keys (AFAIK by comparing system variable LAST_K).
Try the attached game "HARRISBURG" (to control an ATOMKRAFTWERK : pressing D and also K(for '+') or J(for '-'"), you will open or close the steam valve (DAMPFVENTIL, right upper corner). Or use S and K(for '+') to pull a "STEUERSTAB" out the reactor core or S and J(for '-'") to push it back into the core (upper left corner)..

harrburg.p

(7.47 KiB) Downloaded 508 times

This game cannot be played by joystick, but by using the keyboard ...

Siggi

[siggi]

This is one more example, where multiple keys may be pressed at the same time: while holding the fire button down (e. g. SPACE key), it is possible to move the craft up(A)/down(Q)/right/left:

http://www.zx81stuff.org.uk/zx81/tape/3DDefender

[kmurta]

This is one more example, where multiple keys may be pressed at the same time: while holding the fire button down (e. g. SPACE key), it is possible to move the craft up(A)/down(Q)/right/left:

http://www.zx81stuff.org.uk/zx81/tape/3DDefender

But Siggi, the interface works like this, I don't understand.

The setup program takes into account all valid combinations between keys, such that the interface can respond to multiple key presses.

[siggi]

Indeed, it works like on a real keyboard.
It seems, that I played a game, where also the keyboard does not support multiple keys.
Sorry for the confusion I made

Siggi

[system11]

Does anyone have a spare they'd be willing to part with or know if they're still being made?

[mrtinb]

Does anyone have a spare they'd be willing to part with or know if they're still being made?

OP @kmurta is a regular poster in this forum. You can send him a message.

[Crayon21]

I don't have a physical zx81, Can you make a rom dump or image of the interface for emulation?

[kmurta]

I know that there are still people interested in obtaining a JOY81, but unfortunately at the moment I am unable to start producing a new batch.

I still have some PCBs left but unfortunately the cost to send them outside of Brazil is excessive (more than 30GBP), so I will make the files available here for anyone who wants to produce their own interface at a perhaps more affordable cost.

Feel free to use it as you see fit.

PROGJOY.zip

(1.04 MiB) Downloaded 350 times

[Paul]

I just ordered 20 for europe.
If no one is offering for UK I'm willing to send there too. No sending to rest of the world.
Prices when I received them.

[kmurta]

Remembering that you must provide the piggyback connector, although I think this other solution is better: https://www.zx81keyboardadventure.com/2 ... iGfnhStNoE