Ultimarc A-Pac assistance, please

[1500points]

Did a quick search for a-pac but didn't see anything obvious. thanks in advance for the assistance.

The Technology:
Using an A-Pac which has limited technical assistance from the main sale page- https://www.ultimarc.com/a-pac.html
Win7 PC with Wolfmame 106 and working roms for Tempest and Warlords

The Scenario:
I have hooked up four 5K Clarostat potentiometers and some buttons to the A-Pac.
Plugging the A-Pac into the win7 pc installed the ultimarc driver successfully
In MAME from PC, I can get the buttons to be recognized when doing the mapping from the TAB menu and they are seen as joystick buttons.
But I can't get the pots to be recognized when trying to map buttons in TAB.
--I even tried shorting one of the pot tabs to ground thinking it might be recognized as a button, per something I read on the Ultimarc page....but No Go.
Only one of the pots will work with player 2 in Warlords.
Hoping I am simply overlooking a detail or missed a setup detail.

The Specifics:
My pots have the center tab as the wiper.  I have used an ohmmeter to confirm the center post is indeed the wiper.
I have wired as-
Pot 1 left tab to 1Left on A-Pac
Pot 1 center tab to 1Right
Pot2 left tab to 1Down, center tab to 1Up
Pot3 left tab to 2Left, center tab to 2Right
Pot4 left tab to 2Down, center tab to 2Up
The right tab on all 4 pots are wired to GND

MAME only hasof the analog controls defaulted like, which I presume is accurate, the other items are just keyboard keys:
Paddle 2 Analog = J2 X Axis
Paddle 2 Dec = J2 X Axis -
Paddle 2 Asc = J2 X Axis +

The Help:
Can someone give me some tips on how to get MAME to work with an A-Pac, by getting the button mappings to be the proper joystick axis +/-
If I understand the main page, the pots are seen like joysticks rather than a mouse?
Do I need to manually update a config file from a text editor?

My end goal is to allow the 4 pots to run the 4 players in Warlords.

[PL1]

My pots have the center tab as the wiper which I presume relates to ground in the ultimarc diagram.  I have used an ohmmeter to confirm the center post is indeed the wiper.

The left tab red wire is 5v.

The center tab yellow wire is the "wiper" -- acts as a voltage divider outputting a variable voltage between 5v and ground based on where the wiper makes contact on the resistive element.

The right tab black wire is ground.

The center wiper tab on all 4 pots are wired to GND

DO NOT tie wiper (yellow wire) to ground (black wire) or the wiper can ONLY register 0v so the Analog-to-Digital (A/D) converter in the A-Pac will always read that as position 0.



Here's what is happening inside the potentiometer.

The black resistive element is a resistor.

5v on the top tab and ground (0v) on the bottom tab allows you to select a voltage (a.k.a. "potential") between those values.

A wiper arm slides over (wipes across) the surface of the board, making contact between the silver ring in the center and a point on the resistive element.

The contact point is the bump on the right side of the wiper.

When you center the knob, the arm makes contact at the green bar, giving you 2.5 volts on the wiper. (assuming it is a linear pot)

When you turn the knob to the blue bar, you get 4.5 volts on the wiper.

If you reverse the 5v and Gnd tabs, green will still give you 2.5v and blue will give you 0.5v.




Scott

[1500points]

Thanks.  I rewired while you were typing that reply and updated the original thread.
I can get player 2 working in Warlords

How do I get MAME to recognize the joystick axis +/-  since I can't get anything to recognize when trying to map from TAB?

[PL1]

Thanks.  I rewired while you were typing that reply and updated the original thread.
I can get player 2 working in Warlords

How do I get MAME to recognize the joystick axis +/-  since I can't get anything to recognize when trying to map from TAB?

First things first -- verify that the pots work in Windows.

Open "Control Panel"/"Devices and Printers".

Right-click on A-Pac, Game Controller Settings.

You will see two A-PAC Gamepad devices.  Select one and click on "Properties".

If the pots are wired correctly, the X-axis and Y-axis pots should move the crosshair like an etch-a sketch.




Scott

[1500points]

That's pretty neat, had no idea that area existed.
Yes, the 4 pots controls the cursor in the 2 test screens.

[PL1]

Good.   

Verify that the Dip Switch for "Cabinet" is set to "Cocktail" (the Upright cab was only 2-player) and the video is set to either Standard or Pixel Aspect.
(Disclaimer: There might be different different Dip Switch settings and/or video options for MAME 0.106  )

Highlight "Paddle Analog", press enter, and turn the P1 pot -- should map the related gamepad axis to that input.

Highlight "Paddle 2 Analog", press enter, and turn the P2 pot.

Highlight "Paddle 3 Analog", press enter, and turn the P3 pot.

Highlight "Paddle 4 Analog", press enter, and turn the P4 pot.

That *should* map all of the pots.

You'll also need to wire and map a pushbutton for each player (doubles as both "Catch" and Start), and either one (or two) coin buttons.

That gives you a total of 4 pots and 5 (or 6) buttons for your dedicated 4-player Warlords cab.

EDIT: Just noticed in the OP that you also want to play Tempest on this system. (not sure how well this will work with a pot instead of a spinner  )

That means you'll need 2 buttons (Fire and SuperZapper) for each Tempest player (you can remap Start to Fire) plus one or two coin buttons.

Have you chosen/tested the front end software?

Can you navigate it using the potentiometer(s)?

Any other games you want to include?
-  Arkanoid
-  Block Block
-  Bomb Bee
-  Cutie Q
-  Destroyer
-  Field Goal
-  Fire One
-  Free Kick
-  Ghox
-  Gigas
-  Goindol
-  Kick
-  Major Havoc (not sure how well this will work with a pot instead of a spinner  )
-  Off the Wall (uses 4 buttons per player  )
-  Pong
-  Riddle of Pythagoras
-  Sea Wolf
-  Sea Wolf II
-  Super Breakout
-  Up Scope
- Wall Crash


Scott

[1500points]

Hurray!
I just tried the tab mapping again and it worked. whew.
All 4 pots control all 4 players.
Yesssss!  Warlords has gotta be one of the best 4 player games of all time!  So fun, and it translates well to this era of gaming, too.

The setup specifically became

Paddle Analog = J1 X Axis
Paddle Dec = J1 X Axis + (spin counter-clockwise)
Paddle Asc = J1 X Axis - (spin clockwise)

Paddle 2 Analog = J1 Y Axis
Paddle 2 Dec = J1 Y Axis +
Paddle 2 Asc = J1 Y Axis -

Paddle 3 Analog = J2 X Axis
Paddle 3 Dec = J2 X Axis +
Paddle 3 Asc = J2 X Axis -

Paddle 4 Analog = J2 Y Axis
Paddle 4 Dec = J2 Y Axis +
Paddle 4 Asc = J2 Y Axis -

I will toy with the other roms and report back.
Then I need to figure out how to enter the above in the advance mame .rc file for the retropie project.  I put out a feeler in the retropie forums and have some tips for exploring the process now.

UPDATE- Does not work well with Tempest.  If you turn the pot really slow it'll make about 1 revolution in one direction.  If you turn the pot too fast the player jumps/twitches and doesn't move very far.  Spinner games like that work great with the GGG Turbo Twist 2 spinner, instead.