help multiple grounds gamepad
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  1. #1
    Tech Mentor fbonito's Avatar
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    Default help multiple grounds gamepad

    hello.

    i've found this site that explains how to wire gamepads:

    http://www.slagcoin.com/joystick/pcb_wiring.html

    in the site they talk about "common grounds" or "multiple commons"

    many gamepads have just one ground, but there are some gamepads that seems to have diferent grounds.

    that is the case of my hacked gamepads, and that is the problem...

    i've manage to connect everything well, in my project, each button has a LED that lights when pressed, the LED is connected to a 5v supply, works great with most of the buttons, but in some buttons it doesn't work.

    for example:

    button 10 and 9 share one common ground, iff i connect the LED i doesn't work...

    with the multimer i have 2v for the buttons and GND
    iff i try the +5 and GND i get 0.5v
    iff i try the GND with the common ground (from buttons 1 to 8) i get 5v

    has you can see it's a mess... and i'm not getting there...

    does any one have experience with this type of gamepads?

    :-|

  2. #2
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    Are there traces on the top side of the board?

    Can you take a high-res picture of the top side? the one you have of the bottom is perfect... I'd like to see what traces go to what components... The buttons could be in a matrix, in which case knowing the exact circuit layout is vital...

  3. #3
    Tech Mentor fbonito's Avatar
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    Default

    hello,

    thanks for the answer, i will try to take a hi-res picture from both upper and lower side of the pcb, although i have everything solder by now (also with hot glue)

  4. #4
    Tech Mentor fbonito's Avatar
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    Default getting somewhere

    hi,

    i've made some progress on this issue...

    i don't really understand how it works but i've manage to connect some buttons, has i said i looks like it works in some sort of a matrix, and it looks like (i don't know iff this is possible) depending on the combinations, grounds are +5v and positive are grounds...

    for example the 9 and 10 share one ground, but when connecting the LED in the end it looks like 9 and 10 are two different ground sharing one positive, and to get the LED to work i have to connect to the 1-9 common ground and not the +5v...

    well it's a nightmare...

    i didn't get the pictures since the PCB is all glued and placed on a box...

    the good news is that i'm getting somewhere and managing to connect everything...

    it's all about triall & error and diodes, but still a nightmare

    :-)

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