pac-man joystick with mame keyboard hack

[jmbrissie]

i have an upright pac-man and wanted to do some testing with mames save state, etc, for practice. i also have an extra control panel and some original joysticks so i thought an easy way to play with an original joystick would be with a keyboard hack. i created it with an original wico leaf switch joystick (used for pac-man replacement) and a 1990 keyboard with a heavy easily soldered pcb. when i play mame with the joystick one direction will end up not responding. for example if i take sharp turns up, left, then down, the pac will not go up. when i flip to mame using tab the screen is scrolling down because the down arrow is stuck but none of the switches are touching. the joystick switches are wired to the directionals. i was thinking about getting an i-pac or something but this is really bugging me and i dont want to buy an i-pac then find out the original pac-man joysticks need to be modified.

so could this be ghosting, old keyboard, joystick, bad choice with the direction keys, or something else?

strange thing is i can never get it to happen with a keyboard w/o the hack although i havent tried it with a really old one like i used for the joystick.

thanks for any help

[rescue161]

Which keys did you use to make the directions for the joystick?  Of the keys that you used, do they cross on the matrix?  Did you map out a matrix?  I better that you are using a wire that is crossing and creating or ghosting another key.

I mapped out my keyboard with Excel and then used keys that would never ghost, then changed them in MAME.  They are ODDBALL all the way.  If I had to do it again, I'd probably go with the IPAC, but learning the matrix and making my own gave me a lot of satisfaction.

Good luck!

[jmbrissie]

unfortunately i didnt know about ghosting and how important the matrix is when i did this. i picked the 4 arrow keys. that was probably the worst pick, right? i wanted to use the rest of the keyboard as a keyboard and just have the 8 wires coming out of the arrow keys part connected to the joystick.

so if i just pick 4 keys that are on different rows and different columns that should be the easiest im guessing since im only mapping 4 directions.

thanks a lot,
jmbrissie

[rescue161]

There are several programs that you can use to help you along.  Here are a few: Ghostkey, Keyhook, Keyjammin & Keyscan.

If you want the matrix that I made in Excel, I can send it, but it'll probably be different that your keyboard.

I still believe that you are crossing connections on you particular setup.  Do you have an Ohm meter to see if the contacts on the joystick are connected electrically to other points, i.e. ground from one contact to the other?  Make sure that you keep wires from one side of the matrix on that side and wire from the other on the opposite side.  I know that sounds silly, but it will help you elliminate some of the problems.

[Tiger-Heli]

You posted more info in the E-mail you sent me, so I'll repeat that here for others:

i have an upright pac-man and wanted to do some testing with mames save state, etc, for practice. i also have an extra control panel and some original joysticks so i thought an easy way to play with an original joystick would be with a keyboard hack. i created it with an original wico leaf switch joystick (used for pac-man replacement) and a 1990 keyboard with a heavy easily soldered pcb. when i play mame with the joystick one direction will eventually (1 to 3 minutes) end up not responding. for example if i take sharp turns up, left, then down, the pac will not go up.
when i flip to mame using tab the screen is scrolling down because the down arrow is stuck but none of the switches are touching. the joystick switches are wired to the directionals. i was thinking about getting an i-pac or something but this is really bugging me and i dont want to buy an i-pac then find out the original pac-man joysticks need to be modified. when i play and dont cut the corners tight and let the joystick center after every turn or just take 4 way movement instead of turning into the next direction everything works fine but its impossible to play well like that.

so could this be ghosting, old keyboard, joystick, bad choice with the direction keys, or something else?

strange thing is i can never get it to happen with directional keys on a keyboard w/o the hack although i havent tried it with a really old keyboard like the one i used for the joystick hack.

Question - is the game always stuck with the screen scrolling down?  Or is it sometimes stuck scrolling up or left or right instead?  (Doesn't really tell me much, but I'm curious).

Okay - now let's look at what your problems could be.

It it not ghosting - (will surprise a lot of people) - ghosting/blocking occurs when three keys are pressed at the same time.  Pac-Man will at most activate two.

Likely is not choice of keys.  The directionals are a poor choice, and would make for sluggish response, but not okay play for 1 or 3 minutes and then a supposed stuck key.

It really sounds like the joystick is somehow overflowing the keyboard buffer and creating the apparent stuck key.

Ideas -

Check for key-repeat settings in Windows and disable them (although MAME usually ignores these).

Check you wiring for bad soldering or any possibility of wires creating a stuck key even if the joystick is not stuck.  Check the operation of the joystick leaf switches.

Is there an analog joystick (gameport, USB) connected to the computer - if so disable it in MAME - sometimes these can get stuck out of calibration (down) and fight for control with MAME.

All I can think of so far -

Oh - like Rescue 161 said, fire up Ghostkey or similar and see what happens when you use the joystick and whether any keys get stuck in that.  Also just test it out in notepad also. . .

HTH.

[jmbrissie]

i used ghostkey, keyjammin, and keyhook, with all 3 programs i got to keep the left arrow to remain on with the switches open and joystick centered. when i moved the joystick in circles, ghostkey would produce a 3 key sequence then would keep left displayed until i hit left again. i tried to reproduce the other key malfunctions in pac-man and could only get the right direction to not work (left key sticks or does not reset). so i will look at the left key wiring and maybe redo it.

thanks for all of the help,
jmbrissie

[hanelyp]

I second mapping the key matrix, or at least the keys you intend to use to check for conflicts.  The keyboard I'm hacking is organized into 8 collums and 17 rows.  With the arrow keys, shift, control, return, space, and a few other prefered keys all on seperate rows, I don't expect any conflicts using my prefered keys.

As a side note, an older keyboard I mapped, the one currently hooked to my computer, and every other one I've played games on, I've never noted a ghosting problem with arrow keys alone.  I have seen ghosting problems between arrow and other keys.

[SirPeale]

I will second the notion that GHOSTING IS *NOT* THE ISSUE HERE.

The arrow keys are a find choice for a Pac-Man control panel.  All it has is one joystick, a P1 start and a P2 start.

I would also guess at a keyboard buffer problem. 

Go into the BIOS and check the Typematic Delay settings.

[Kremmit]

You can get behavior like that if you accidentally wire to the NC connection of a microswitch instead of the NO connection.  But you say you're using leafswitches, so this doesn't apply to you.  I only mention it for future readers with similar symptoms.