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Buttons activating by touching a wire

  1. Aug 7, 2009 #1
    Hello, so I recently modified a gamepad to make my own arcade controller. However I have run into an issue which I do not quite understand. Sometimes the left button will trigger for no apparent reason when the down button is being pressed.

    First of all, each of my wires to each button have a solder joint which is covered with electrical tape. So I examined it and I found that if my hand was near, or touching the solder joint (covered in electrical tape) of the left button while I was holding down, the left button would fire.

    What's going on here? And how can I shield it so that it stops?

  2. jcsd
  3. Aug 7, 2009 #2
    1) High impedance input maybe.
    2) More tape
  4. Aug 7, 2009 #3
    Thanks for the reply, I read up a bit on high impedance and it sounds like that might be the case.

    I tried adding more tape like you suggested though, and I still receive the same problem. It is really odd, it only happens where there is solder joining the two wires. If I touch the electrical tape it will trigger, but if I touch the insulation on any of the wires it won't.

    I should probably also mention that the connection goes from a solid wire to a braided wire to a solid wire again (I don't think that should change anything but I figured it would be worth mentioning). Additionally I have a resistor on one wire.

    So I decided to cut all the wiring going to the directional buttons, however the problem continues to persist. I can press down on the tangled wires of the other buttons and it will cause the same problem to occur. I have a feeling it is my the controllers problem, so I might just have to replace it.
    Last edited: Aug 8, 2009
  5. Aug 8, 2009 #4


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    Hi, Briant.
    I tried to respond to this question first thing this morning, but as you can read in GD, my internet connection has been giving me fits for a few days. I started trying to get on line at 8:30 this morning, and just managed to do so an hour ago (8:00 pm).
    Anyhow, electrical tape should never be used unless there's no other option. Heat-shrink tubing is far superior, or you can paint the joints with liquid latex, silicone sealant, or potting compound. My best guess is that the physical proximity of your finger to the joint is causing a temporary short to the second pad. I doubt very much that your body capacitance would be sufficient to cause such a malfunction. Also, make sure that there are no cracks in the circuit board, since those can also lead to shorts.
  6. Aug 9, 2009 #5
    Thanks for the tip, ill be sure to keep this in mind when I rewire it.
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