Electrically disable this PCB from radiating

NaomohNaomoh Joined: Posts: 1
I recently cracked open an Xbox One controller, the impetus for doing so was two-fold:
  • First and foremost the engineer in me likes to see how things work under the hood as I learn a great deal that way
  • Secondly, I wanted to mod my existing Xbox 360 fight-stick controller to work with the Xbox One by splicing into the Xbox One's PCB for button presses; this is colloquially called "pad hacking."

I was able to successfully mod my controller to utilize the Xbox One's PCB and now my attention is aimed at electrically disabling the wireless functionality. The reason this is necessary is that wireless communication is forbidden in fighting game tournaments due to the possibility of your controller affecting the inputs of your opponent (or vice versa.)

It's been a loooong time since I studied RF but I'm fairly certain that the antenna circled in blue in the picture below is an Inverted-F Antenna (IFA), is this correct?

I had thought that physically de-soldering the antenna would prevent the controller from wirelessly connecting, but I was wrong! It still connected at a distance of about 6-8 ft.

Next I thought that cutting the trace on the bottom side of the board leading to the antenna (shown in red) would surely do the trick but again I was wrong; it would still connect if I was within a foot or two of the Xbox One. As an aside, what exactly is that trace's functionality? Continuity tests shows to be at ground potential (this board has a common ground). Originally I thought this was the feed line but now I'm thinking this is the shorting trace which acts like a parallel inductor(kynix.com/Product/Cate/448.html). Any ideas?

So what kind of voodoo is going on here, I had thought that to get a device to properly radiate in a functional manner requires all the right parts in all the right places. This board, however, seems to be built like the terminator; it just keeps working. Besides putting it into a Faraday cage, can anybody offer up suggestions on how to electrically disable this PCB from radiating?

As a side note, I'm not 100% sure what frequency band the Xbox One controller uses but if I had to guess it would be 2.4Ghz as that is what its 360 predecessor used.
7Q3Nl.jpg
77cnO.jpg

Here is zoomed in picture of the trace that I cut. I followed the trace with blue dots so you can see how it connects to the antenna on the other side of the board. The trace appears to have an SMA connector as well as AC-coupling cap in series.
F3tzv.jpg

Comments

  • DarksakulDarksakul Your lack of faith disturbs me Joined: Posts: 24,273
    Except we found that cutting the antenna does not kill any transmissions to the console.

    “Strong people don't put others down... They lift them up.”
    - Darth Vader, Philanthropist
  • VarmintBabyVarmintBaby Joined: Posts: 586
    What game did you intend on playing in tournaments on Xbox One? Most fighting games are played on PS4 in tourney. You may be giving yourself a headache for nothing.
    "Play the game to learn not to win. Do this and winning will start to come all on its own." - some smart guy
  • DarksakulDarksakul Your lack of faith disturbs me Joined: Posts: 24,273
    For the effort, just go with the Brooks UFB
    “Strong people don't put others down... They lift them up.”
    - Darth Vader, Philanthropist
  • FreedomGundamFreedomGundam Freedom, ikimasu! Joined: Posts: 2,533
    edited December 7
    Naomoh wrote: »
    Secondly, I wanted to mod my existing Xbox 360 fight-stick controller to work with the Xbox One by splicing into the Xbox One's PCB for button presses; this is colloquially called "pad hacking."
    Actually, while it is a padhack, in your case, it would be more correctly called a "dual-mod", since you're modding a second (hence "dual") function into your setup.

    Anyhow, I thought the trace to be cut to disable the wireless was near the bottom left side of the underside of the board?

    *EDIT* Found it in the XBO padhack thread:
    http://forums.shoryuken.com/discussion/comment/8629516/#Comment_8629516
    Current at-home stick: Hori VLX Kuro (LS-40-01 + PS-14-K)
    Current portable stick: Mad Catz TvC (LS-40-01 + PS-14-KN)
    Current guest-sticks: custom ABS Modular stick (JLF + OBSN-30), custom Saint-stick (Happ/IL Competition)
    Cabinet: custom "Resistor" cabinet (32" LCD, X360, P1=LS-32-01 + PS-14-KN, P2=JLF + OBSC-30)
    Previous sticks: custom Happ CvS2 Double-sticks, custom Happ Hitomi-stick & Xenosaga-stick, custom Sanwa/Seimitsu Neptune-stick and Sylvia-stick, modded Mad Catz TvC, modded Mad Catz Brawlstick, modded Hori FSVX, modded Exar Exaprize

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  • DarksakulDarksakul Your lack of faith disturbs me Joined: Posts: 24,273
    FYI some tournaments can still bad the stick for the PCB, wireless disabled or not
    “Strong people don't put others down... They lift them up.”
    - Darth Vader, Philanthropist
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