Neo-Geo credit displays. How to recreate?

[LeedsFan]

I have decided that my latest project will be based on a two player Neo-Geo layout with appropriate artwork. I thought it would also be cool to build in the double digit LED credit displays as on the original cabinets. I'm building this from scratch so I have no original hardware. I just wondering how easy it is to wire up something like this and if anyone else had already tried it?

I think I may have to wire them up so that a separate circuit is used each time the credit button on the panel is pressed. (I will have separate small credit buttons for each player to the right of their respective start buttons) That's not too hard but of course the credit has to go down one for whichever player is next "up" and his game starts. So wiring up to "1 Player Start" etc. seems logical enough.

All this of course has no direct correlation to the credits displayed in Mame. I don't think there is any way to control these LEDs from within Mame itself, though I could be wrong.

However my problem is that I have very limited electronics experience. I need a wiring diagram as to how to rig this system up, and that's assuming the way I am thinking it will work is fine. I don't mind fiddling with breadboards or soldering etc.

[Ed_McCarron]

If you want to avoid programming, try a 74192 counter with a 7447 driver -- google will produce tons of ideas.  You'll need one set for each digit, and a source of 5v, and a nice debounced switch.

Or, work on some programming skills and use a basic stamp or arduino to handle it all.

If the credits get out of sync with the MAME software, all bets are off.

[CheffoJeffo]

Someone here in Canada was doing exactly what you describe. Damned if I can find the thread though.

[JustMichael]

Someone here in Canada was doing exactly what you describe. Damned if I can find the thread though.

Did you mean this thread?

[Malenko]

just for clarification, there's 2 single digit LED displays and not a double LED

[CheffoJeffo]

Someone here in Canada was doing exactly what you describe. Damned if I can find the thread though.

Did you mean this thread?

You, sir, are a super-hero -- that is the guy.

 

[LeedsFan]

Well I've just read the entire 5 pages of that thread.... that is one awesome build so far!!!  

There's no way I could do what he has done with designing a circuit and having someone build a pcb for him. That's way out of my league I'm afraid. The best I've come up with so far by Googling is this.....

http://www.techcraftngrafix.com.sg/electronics%20kits.html#2d_ctr

They are based in Singapore and the prices are in Singapore dollars. I would buy the pre-made and tested modules for the little extra they cost. Not sure if they would work on a 12V PC supply as in those pics they seem to take a 9V battery. I've emailed them about this and also shipping costs.

I would also unsolder the 7 segment displays from the boards and remount them in reverse just as Yvan did to help mounting inside the CP. That's a very clever idea that I never thought of!!!     (EDIT: Just realised that if I do this the board will be turned thru 180 degrees, meaning most of the pcb will be above the display when mounted.  Not sure if I will have the room. Might just have to unsolder and add new 7-segment displays with extended legs)

I can simply wire up the buttons on the pcb to the credit and start buttons on the CP. Of course I will be in the same situation as Yvan in that the credit display won't be totally authentic. By wiring it this way you can add credits to the CP display at any time... even when in the frontend. And use them up at any time too by just pressing "Player start" buttons. I can't think of any way round this. I can have the credit display reset to zero when pressing "Game select" and also when pressing "Exit" to get to the frontend menu. That's about the best that can be achieved I think.