| Ken's MAME Project ... to be continued - maybe
This page is about what can happen when you've got:
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| Update: June 3 2001:
For the curious - A few people have written asking for dimensions. dimensions.jpg We have been experiencing problems with 4 players missing button presses. No ghosting is occurring, but when 4 people go at it, movement is not very responsive and not every jstick movement registers with Mame. I haven't debugged it, but I suspect either buffer loss or the keyboard chip is simply not reporting the switch closures fast enough or Mame itself can't interpret the presses with my particular hardware. I'm leaning towards buffer overruns. I'll let you know when I have some time. Maybe someone else out there has experienced this???. |
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In Feb. 2001 , a few years after everyone else, I discovered MAME. Having been an arcade service tech for many years, you know, the guy who fixes the joysticks, the pinball flippers, and the crane claws, I felt obligated to strap some real arcade controls to this MAME thing. I'm not in that industry anymore, so after I discovered WICO went out, I found HAPP controls, and they were the easiest to deal with online for ordering the joysticks and buttons. I really don't want the coin doors (yet). I wanted a four player panel. Yes, this IS a lot of wiring. My configuration concept was 4 Street Fighter style ( 6 button ) stations. This would allow me to have 2 sticks near each other for dual stick games like Ikari Warriors and Smash TV. Here's the layout ( BIG IMAGE )
I'm skipping the photos of the wood cutting and the button stuffing because they're boring. BUT, here's the button templates I used ( they're exact in inches - print them on a laser printer at 100% , tape to a board, and drill. ) 6 button template + joystick pattern The GUTS: Inside the box is
side notes - most pc keyboard use a technique called a matrix to read the switches. The advantage of this method is you can read a lot of contact points with very few IO devices. My keyboard had 13 x 8 connections points ( 104 possible keys to press ). Normally, humans only press one key at a time ( yes, even fast typists ). When playing video games, especially with 2 of more players, we get: Player 1 stick up + fire + Player 2 stick left + jump etc. This leads to keyboard "ghosting" on standard keyboards. Ghosting is when you press 2 or more keys and some additional keys seem to get pressed all by themselves ( I hate to have "reset" get pressed in the middle of a game of "1941" ). The diodes prevent the flow of current in a matrix to other switches on the same x or y segment. Most electronic pinball machines use matrixing w/ diodes. I've never seen a pinball not use matrixing, but I'm sure there's that one out there ... Anyway, what would happen in Pinballs was that a diode may short and cause all kinds of havoc ( like having no diode at all ). In reality, mostly the diodes broke there connections and no switch got closed, but that's another web site all together. Heres the Keyboard PCB. I've desoldered and removed the original flat membrane connectors and replaced them with ribbon cable for the x and y segments. I ran these cable to the radio shack pcb and added a diode at every point where x and y intersected. For those of you not watching, my board is the ugly one with all wires running to it. It took 2 days to wire the board, mainly due to hunting down the standard MAME keys ( ESC, TAB, ENTER, etc. ) and the fact that I get distracted easily these days - I kept testing player one's hook up for a big chunk of day 1 :)
OK - Big Picture stuff: The Internals from a few feet
The Layout ( what does what ) - Having the individual starts on each players stations helps - it's combined with player button 6. Note - under mame players 3 and four only have 4 buttons, so button 5 and 6 on players 3 and 4 can be multifunction. I didn't know this when I cut the wood, but have made up this perfectly logical excuse to conceal my error - so in the M$ tradition, we'll call it a "feature".
I've tested using ArcadeOS and MAME for DOS. I had a very strange problem occur where is I hit player 1 start and payer 2 start simultaneously ( using keys "1" and "2" - the mame defaults ) the game would reset as if I had hit the Escape key. I tested this with 2 other keyboard on this system ( ruling out my contraption ). Pressing keys "1" and "2" would reset any game. I remapped player 2 start to the "Page Down" key and now all is fine. My wife and I made it all the way through "Sunset Riders" without a hitch, burp, or glitch. Yippie!. --------UPDATE--------- Problem fixed - some helpful Mame users informed me that the problem is not really a problem, but a feature in ArcadeOS. Open "arcadedos.cfg" and change "start12esc=1" to "start12esc=0". --------------------------- For the curious, the project cost about $175 ( wood, screws, jsticks, buttons, lunch, radio shack, etc. ). In retrospect, it would have been a better idea to find a game cabinet, with monitor, in the $100 - $200 range and put the MAME system inside. But, like most home projects, the fun is in the building. PS - Don't Use Particle board - you'll regret it later - I know real arcade games use it, but this is for my home and I didn't want to lug and 80 lb. console around. I made this with 1/2" quality plywood and it's light ( about 10 lbs. ) Next stop - The monitor, cabinet, and other junk - but not today :) enjoy - You can contact me via Rainfall contact form http://www.rainfall.com/contact.asp Ken Anthony
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