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Switching Multiple Circuits Simultaneously

Discussion in 'General Electronics Discussion' started by rbbauer00, Feb 1, 2016.

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  1. rbbauer00


    Feb 1, 2016
    In essence, I am looking for a multipole, multi throw switch in order to change between player modes on an arcade cabinet. I need to switch 2 groups of 13 momentary switches between 4 groups of low voltage DC inputs.

    I am building an arcade cabinet that uses a PC to emulate many different games. The control panel uses momentary pushbuttons (microswitches), all connected to a common ground. The positive terminal of each button is connected to an individual screw terminal on a PCB that, when closed, emulates a USB keyboard keystroke to control the game. The product I am using is called Ultimarc I-Pac 4 (first pic below). It has 56 individual inputs, which would allow up to 4 players with up to 8 buttons and a joystick each.

    My cabinet design calls for 1 joystick and 7 buttons per player plus a coin and start button for each. Each joystick uses 4 inputs. This means each player requires 13 inputs x 4 = 52, giving me 4 extra inputs to use to control the PC itself. Because I will primarily use this machine alone or with one other player, as well as to keep the user interface from being ridiculously large and complicated, I am planning on having only a 2-player control panel on the cabinet. This is fine for about 90% of games.

    The problem comes when 4-player games require a certain player number in order to select the character you play as. For example, in the Teenage Mutant Ninja Turtles game, player 1 is Leo, player 2 is Mike, 3 Don, and 4 Raph (or something like that). If I only players 1 and 2 wired into the ipac, I cannot ever play the game using the latter two characters.

    I want to be able to select which player number I am by switching each group of controls between player inputs. What I have in mind is a rotary switch with 4 positions on each side of the console. However I cant find a 13-pole, 4 throw switch. One probably doesn't exist. I'm sure if it did, it would be prohibitively expensive anyway. Buttons and joysticks are cheap, so if a cost-effective solution isn't possible, I'll just build the control panel with 4 player inputs.

    Some possible solutions I thought of:
    -Stringing together 13 SPDT relays on each side all with a common control circuit hooked up to a SPST toggle.
    -modifying a pair of 4-way KVM switches
    -using an arduino

    The relay thing seems simple and effective, but would give the left player only the option of Leo or Don, and the right player only the option of Mike or Raph. No playing with Leo and Don together or Mike and Raph together :(

    On the surface, having each group of 13 inputs to a KVM (or something similar) that could switch between 4 sets of inputs seems like it would work. A VGA cable has 15 pins, 2 more than I need. But is a KVM or VGA switch basically a 15 pole, 4 throw switch, or is there more to the inner workings that would make it interfere with the signals from the arcade buttons ? I found these (2nd pic below) at monoprice. Also this one (3rd pic) might be more aesthetic if I swap out the pushbutton for an arcade button and extend the LED's to the control board on the cabinet. Will this work?

    I don't even know how an arduino might do this, but maybe someone out there does...

    I hope my explanation of this problem makes sense :)

    The Ipac 4:

    Manual VGA Switch:


    Electronic VGA Switch:

    This is not my console design, but gives an idea of what I am going to build:
    Last edited: Feb 1, 2016
  2. Alec_t


    Jul 7, 2015
    Since you are using a PC to run all the games, can't you just use one SPDT switch to tell the computer to switch characters and execute appropriate routines?
  3. Merlin3189


    Aug 4, 2011
    I must admit I can't understand what you are asking, so this may not be the answer. (You appear to have all the inputs you need.)
    If you want to enable each bank of switches, you can control the common line to each bank. Since the button inputs on the iPAC are active low, if the common to any bak is held high, those buttons are disabled. To activate a button bank, simply bring the common line low.
    Alternative banks would need to be connected to shared iPAC terminals through OR gates, which can be simply implemented by diodes.
  4. rbbauer00


    Feb 1, 2016
    My problem is not in the number of inputs, but rather having the ability to select which input I am using. The ipac is setup to have 4 separate controls hooked up, but I want to only use 2 controls and switch them between inputs.

    I guess the root of my question is do these vga switches simply act as a multipole/multithrow switch that passes through all signal from the input to the output side or is there any circuitry inside the VGA switch that will interfere with signal, especially since I am not using it as intended. I want it to be as though I was unplugging all 13 buttons from the player 1 input on the ipac and reinserting them into player 2,3, or 4.

    Assuming it works, I plan to use 2 VGA switches, one for each player. The controls would be connected to the input side of the switch and the four outputs from VGA switch connected to the 4 sets of inputs on the ipac. Both switches' outputs would be connected in parallel to the corresponding ipac input. Each player would then have a selector knob or button that would toggle them between 1,2,3,and 4 on the ipac.

    I believe the VGA switch is the solution. For 25 bucks, I'm at least not out much money if it doesn't work. The manual switch seems like it is more likely to do what I want, but the electronic switch would be more aesthetic since I wouldn't have that large, black knob sticking out.
    Last edited: Feb 1, 2016
  5. rbbauer00


    Feb 1, 2016
    The game software itself is not designed to have a player select a character within the software, but rather the character is selected by which set of controls the player chooses to use.

    I could probably setup up different keymappers as a software solution. However with one or two players each choosing between 4 characters, there are 16 possible player combinations. This would require 16 separate keymappers and one would have to be selected prior to loading the game. I'm looking for more of an "on the fly" solution so each player could choose his character while the game is being played.
    Last edited: Feb 1, 2016
  6. GPG


    Sep 18, 2015
    What voltage/current to switch? There are many analog switches.
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