can I get 3 buttons out of an optipac?

[Ghoul]

Well it's going to be a while before I have a full-fledged arcade cabinet, so in the mean time I decided to build a cheap stand-alone trackball cp since I already have all the parts.

It's basically just a box with a happ trackball and 3 buttons wired to an optipac. Kinda like Stein's http://webpages.charter.net/mjellis1/ only much simpler and less professional because it'll just be hack job.

I was wondering, how can I get different 3 buttons to function using only an optipac? I thought that there was only an option for 2 mouse buttons? Stein's has 3 so I know there must be a way without having to use an ipac and I really want 3 buttons. Please help me out, this'll make it a lot more fun to play missile command =)

[Brad Lee]

I'm not sure exactly "how" to do it, but there are inputs for 2 mouse buttons for player 1 and 2 each, so 4 mouse button inputs theoretically

[paigeoliver]

If you just want to add a couple buttons to your little box. You can use the joystick port.

http://www.zeta.org.au/~msmcdoug/joystick.html

Pin 4 is ground, and pins 2, 7, 10, and 14 are buttons 1 through 4. Not usre if you would have to wire the stick part as well though.