How does a dual mod work?


#1

Hi, I was trolling around a bit, and have seen many dual mod videos, threads, and other things around. Although a lot of the things i see are quite in depth, i still can’t grasp the concept. All i know is: There is 2 PCBs, hooked (usually) up to a single usb, and a imp board to act as a switch to switch from one pcb to the other. What i want to know though, is how the button wiring is done. Like is it wired to one and linked to another or something?


#2

it is easy to do if you have a xbox 360 stick. and if you want just to play on the ps3 and pc. just get a CHIMP, CHIMPSMD, TEasy, or something like that and thats is it. Only time when you want to have a dual mod when you want to go wireless or you are starting with a ps3 stick u will need both ps3 and xbox360 pcb but thats just IMO. if you go with the route i just stated you do not need a ps3 pcb. plus if you have a ps3 stick some sticks out the box do not work on the pc depending on what you have in it(PC configuration).

But in a nutshell i would reccomend just browsing the Chimp and Cthulhu thread and the TEasy and what not. The Teasy requires no soldering which some ppl like but its you to you or the modder what method they want to use to keep the work clean ya know.

http://shoryuken.com/f177/project-teasy-mod-your-solderless-solution-te-dual-modding-234867/

http://shoryuken.com/f177/official-cthulhu-chimp-thread-162026/

If you already have a xbox360 stick. you are half way there. just get a board and mod away. if it is your first time modding or soldering, buy some extra solder and practice before you try for the first time. if you dont want to solder go either TEasy or talk to any of the great modders here to hook u up. I would but I am up and coming and must pay my dues before stepping up but you have Upas, Gummowned and other who do great work and prices arent bad.


#3

Read up on the PCB section on slagcoin.com

I’ll attempt to summarize: a button press is triggered when a “signal” line makes contact with a “ground” line. Literally, like two wires touching each other. Dual mods (the easy ones, anywas) are done with PCBs with “common grounds”, which means they have many signals, but the same ground. In a dual mod, the grounds from both PCBs are connected, so they basically both share one ground. You then hook up two signals (one from each PCB) to each button, and they can use the same ground line.

The thing about hooking up signal lines, is that you don’t need to get two signal wires to each button - you can just put the wire from PCB1 to the corresponding signal directly on PCB2, or put then on the same point on a terminal strip. (When things are connected by wire, you can treat them as if they’re just touching each other directly - because they are).

Other stuff:

  • both PCBs need to be powered at the same time for either one to work.
  • What the imp does is make it so that only one pair of the data lines (from the USB cable) are connected at once, even though both are being powered. A DPDT switch does the same thing, but requires mounting a switch somewhere.
    (a chimp is just a combo of the cthluhu (a ps3 PCB) and the imp)

I’m sure my terminology is all wrong, but that’s the idea, if you can make yourself read all that =P.


#4

I don’t need advice, i’m not doing one, i just want to figure out the idea.


#5

my bad. since i saw ur joystick thread i assume. jaytoo answered ur quesiton it seems


#6

check the stickies

there is a giant dual modding thread in the essentials sticky


#7

I will look into that, but usually in the threads I look at it’s either people showing how they did it, or other stuff, but not really explaining how it works. Anyway I think i have the idea now.


#8

The reason I suggested it is there is an extensive explanation of how it works. Like seriously, check it.


#9

Okay. I’ll give it in a nutshell.

Firstly, we have to understand how a single common ground PCB setup works before we can understand a double PCB setup. The concept of common ground is that for every component in the circuit, the ground side of the circuit is all the same wire/connection. Every button has two wires attached to it, one side is ground, the other is signal. You can see this in pads very easily, look at any padhacking diagram (IE http://slagcoin.com/joystick/pcb_diagrams/360_diagram3.jpg). The signal wire is constantly at 3.3V or 5V, depending on the system. We’re going to assume this is PS3/360 wired dual mod, so 5V.

By pushing down a button, the two wires attached to the button are connected together, meaning the signal wire is now touching a ground wire, and the 5V of the signal wire is now at 0V, because electricity travels from high to low. With the 5V wire now at 0V, the integrated circuit (microchip) on the PCB reads this 0V. The IC is coded very simply, basically “If this wire is at 5V, the button is not pressed, if it is at 0V, then it is pressed, send this data to the system to be handled by the system.” It then sends data through the two Data + and ? wires to the system found in USB. The remaining two wires in USB are 5V and ground.

Joysticks work almost exactly the same, only they have microswitches directly pushed down by the stick itself, instead of by plungers in the buttons. This is handled in the same signal wire/ground wire fashion as the buttons. You may not notice that each microswitch has a ground wire touching it, but this is because the joystick PCB handles the connections for you. You just need to plug in the wire harness and solder the ground wire to ground on the PCB, and signal wires to the directions. It is handled the same by the joystick.

That is how a single PCB works. Now, to dual mod two PCBs, what you will be doing first is to connect the VCC lines between the two common ground PCBs, and the grounds between them. This is first and foremost, as both PCBs must always be powered at all times.

Next, since our PCBs are common ground, we don’t have to solder any more ground wires between the two, because the PCB handles making every ground connection internally. This is not the case of common voltage PCBs, that instead of having everything at 0V and 5V, things can be 3.4V and 2.7V on the two sides. Because the voltage is so random, there is no way to effectively link two common voltage PCBs. So, don’t use them!

Next up, we simply solder the signal wire to signal wires of corresponding buttons (IE X to A, Triangle to Y, etc), and solder directions to each other. Now, with these linked together, any time you press your A button, its voltage will be reduced down to 0, the PCB read this as pressed. However, since a wire is connecting the signal of X to the signal of A, these are the same wire, so the X on the PS3 PCB also drops to 0V. Any time in a dual mod, because both PCBs must be powered, both PCBs are sending out the equivalent signals for their individual systems. Since 5V and ground are shared, the difference we must look to is in the Data + and Data ? wires.

Now, most people don’t want to have two USB wires hanging out from their dual mod, so we need to be able to have the Data + and ? lines going down the same USB wire. To do this, we need some sort of switch.

The oldest example of a switch was a physical DPDT switch, which means double pole, double throwing. Basically, there are six pins on the back of a DPDT, which should be grouped in twos. What this basically does is whatever two wires in the middle are essentially what is going out to the USB wire. The two on either side are the two wires that we will be switching between, in this case, the USB lines of the PS3 and 360. Wired up, it will look something like this:
XD+ OD+ PD+
XD? OD? PD?
XD representing the two Data wires of Xbox, OD representing the Data wires that are connected to the USB cord that will be connected to the system, and PD, of course, representing the PS3s data wires.

Now, whenever you flip the switch, either the Xbox data wires or PS data wires are the ONLY two going connected to the outgoing USB wire, the other side is not connected to the USB wires, so all of the data it sends to a system is lost because the data lines aren’t connected to anything. Internally, it is trying to send to the system that each button is being pushed, but because the data wires aren’t connected until the DPDT switch flips to connect them.

Nowadays, however, we can have an internal PCB handle the switching of the data wires. Imp boards work much like DPDT, but instead of having to be physically switched, holding down a button (Typically home) will cause the PCB to switch the data wires to from what is soldered to the primary wires to whatever is soldered to the secondary data wires. Dualstrike basically does the same thing, but it combines the switching function with a PS3 board, so that you only have two PCBs instead of three (PS3, Imp, and 360). ChImp is magical and special because it is the only PS3 PCB that can detect which system it is plugged into, and connect the correct data wires to the USB wire.

This is how they work. I hope that all makes sense.


#10

Nerrage, Cherry is a brand of Microswitch, not a type.


#11

>_>. I see, I see.

Never mind, I realize it was implied as a type.


#12

Finally, thanks!


#13

To be more succinct, you wire up the two pcbs parallel to the buttons and joystick. Signals, grounds, and voltages are all connected. Two cords coming out, but only plug in one system at a time.