PS2 keyboard to control jamma arcade board

Hello,

I was thinking of using arduino and PS2 keyboard to test jamma arcade board controls. I have now interfaced the keyboard to arduino and it is working fine. I can flash leds on i/o-pins with keyboard buttons.

My question is how would I go about emulating the button switches with the i/o-pins (without destroying the arcade motherboard)? The buttons in jamma interface work like following. When buttons switch is open the pin is high (5V) and when button is pressed it gets grounded. I'm a little confused how should I connect this. I just don't want to burn the motherboard when I get it. :)

Would it work if I just connect the button pins to arduino pins and configure the pins as input. Then when button press occurs pull the pin low (ground). They would have to be in same common ground of course but can I still power arduino board separaterly or should I power it also from the jamma interface. I'm going to use normal atx-psu for powering the board.

Nobody has nothing to say about this??? :o

to test jamma arcade board controls.

Are you talking about testing the controls (i.e., the buttons and levers in the cabinet)? Or the control input circuitry on the game PCB?

If you're testing the boards, I'd be inclined to use a couple of shift registers: the JAMMA standard specifies 8 switch inputs for each player, so one 74HC595 for each player's buttons works nicely. It's not a perfect emulation of the switches (because the 74HC595 outputs are active in both high and low states, you could miss a damaged pull-up resistor. Also the shift register doesn't bounce like a switch contact. But the switch debouncing is probably done in software, so it's not likely you'll miss a failure), but would probably be good enough. You should make sure the shift registers are installed in sockets: if there's a bad board that's leaking 12V into places it doesn't belong, you could blow up a chip (better a $1 shift register than a $6 ATMega, though). So you'll want them to be easy to replace.

Ran

control input circuitry on the game PCB?

This is just the thing I was talking about. I don't have any buttons or joysticks to test with so thought I could try with a keyboard until I manage to build a proper arcade controller.

At the moment I don't have any shift registers either but I think for testing there is enough unused pins in arduino board.

Here is a video of me playing king of fighters with keyboard + arduino. http://www.vimeo.com/9414469

did you do the stereo mod to that neo-geo? (the arcade version is just wired up on the mobo for mono)

Actually the mobo in the video is sammy atomiswave which has stereo output connector in the front of the unit.

ah! I wasn't aware of the sammy ones having that

sweet