Looking for advice on how to build a bluetooth gamepad case for an Android phone.

Discussion in 'Console Modding 101' started by thejellydude, Apr 9, 2018.

  1. thejellydude .

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    Hi all. I've got a somewhat ambitious project for myself. My favorite phone that I've ever owned was The Sony Experia Play. I was heavily inspired after seeing posts like World's Smallest Gamecube Controller, or DolphinBoy.

    I would like to reconstruct this experience for my Galaxy S7, by designing a case similar to one of these. 1, 2, 3

    I've though of three potential methods to build this case, and was hoping to find the feasibility of each, and see what more experienced modders would suggest.

    Idea 1, build it all myself: I'm hoping to 3D print a case for my Galaxy S7 that can emulate the same idea, using either an Adafruit Feather M0 Bluefruit LE or 32u4 Bluefruit LE as the base. I would then attach two psp thumsticks (or possibly 3DS sliders, if those would work) along with two breakout boards for them for analog controls. In addition I would have two of pigirl boards along with 10 buttons to make the d-pad, a/b/x/y and l/r buttons. Two extra buttons will also be purchased to make the start/select buttons. Finally, I would have a slider to control power for the device, and some kind of battery. How feasible do you guys think this project is? Based on this guide I'm assuming I'd need to design my own PCB, but it doesn't seem to difficult.

    Idea 2, modify it from a 8Bitendo controller: I've seen these controllers online a lot, and they seem pretty cheap and reliable. I found a tear down of one online, and it seems very thin. the main issue would be converting to the thumbsticks into something smaller, such as a PSP or 3DS slider. From my understanding, I would just need to desolder the included sticks, and then solder on the PSP/3DS slider, making sure my X/Y/3.3v cables are wired correctly. Or would I need a microcontroller as well? Either way, this seems like a very viable option to me.

    Idea 3, modify it from a pair of Joycons: I was amazed to see that the majority of a Joycon is the rumble pack and the battery. Once again, the idea would be to build off of something existing, instead of doing it all myself. With this idea, however, I would plan to build new enclosures for each Joycon (To make them thin like credit cards) and then have the S7 case have slots for them to "click" into. This way if I upgrade/change my phone, I would only need to create a new case to hold the modified joycons, not the whole assembly. The downside of this compared to Idea 2 is the need for two bluetooth connections, as well as only having one main L/R button. Once again, I think I would like to take out the actual joystick for a PSP/3DS slider. Is this a relatively simple process?

    Thanks for any and all help guys. I'm super excited about all of this.
     
  2. Fruity_Grebbles . .

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    I too had an Xperia play! Loved the hell out of that thing. Here are my thoughts on your ideas:

    A fully DIY route is likely your best option. Have you considered USB otg instead of Bluetooth? With the addition of minimal height on your phone case, you could do away with wireless hardware and an extra battery. Might simplify things.

    Don't modify the 8BitDo controller. I have one, and while they're lovely and well-built while assembled, they're not worth the time to hack to suit your needs once opened up. The internal components are too specifically suited to the controller's native design.

    Joycons do have tiny components, but that's both a blessing and a curse. Imagine working with tiny, fiddly ribbon cables and pads. Not to mention, they're not exactly cheap.

    I look forward to seeing this project take shape!
     
  3. thejellydude .

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    Thanks for the response! A few things of note:

    1) Fully DIY seems like the best idea to me as well. A big reason why I want to do bluetooth is both for thinness, as you mentioned, but also because it helps make this more future-proof. If I get a new phone, bluetooth is almost guaranteed, while the position of the USB port might change drastically.

    2) Are you sure? It seemed like the 8BitDo would be an almost perfect match, since it lays so flat normally, and is a fairly rectangular shape. I'm curious as what to you mean about "The internal components are too specifically suited to the controller's native design." Couldn't some smartly designed parts remedy that? (I'm assuming you're talking about things like the placement of the shoulder buttons) I'd love to hear from someone who actually owns one of these things.

    3) You might be right about the cables and such. Funnily enough, with my GameStop rewards membership, the joycons are only $48, much cheaper than the DIY option. I also liked this route because of how modular it would make the final design, but you might be right in that it's too much work.

    Do you happen to know anything about how hard it would be to implement a 3DS slider in place of some other input? I'm assuming it's not too bad, but I also haven't ever messed with one before. Anything to save a few precious millimeters of the PSP stick, lol.
     
  4. Fruity_Grebbles . .

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    Paging @Aurelio re: analog stick resistance ranges
     
  5. JacksonS . .

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    Using 3DS joysticks on a different controller usually entails altering the range by using an ADC for input, modifying the value, and outputting it with a DAC. A microcontroller with a separate DAC is a good way to achieve that.

    When given a 3.3V input, 3DS joystick axes output from about 0.5V to 2.8V, centered at around 1.65V. If your controller expects a full 0V to 3.3V range, you'd have to scale the input to stretch it out to the larger range. You could also put some deadzone restraints in there (as in making the output stay neutral when the joystick is within a certain range) because the 3DS joystick is quite sensitive around the center.
     
  6. thejellydude .

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    Thank you for the extremely informative response. This is making me wonder if it's worth using a 3DS slider over a PSP nub. I wish there was an easy way to see the height difference.
     
  7. Fruity_Grebbles . .

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    I can take some photos of the sticks on my controller in profile when I get back from class.
     
  8. fibbef Digimon World Completer . .

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    I still do!

    I should really upgrade though. That phone has not aged well.
     
  9. thejellydude .

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    I feel you man. I held onto mine for the longest time. I work at a job that requires me to travel a lot now, and I miss just being able to flick open my phone and quickly play some Advance Wars or something. The physical buttons make such a difference.
     
  10. thejellydude .

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    So updates on the gaming phone case concept

    This is going to be extremely doable with extremely little effort
    I bought one of these off of Amazon for about $6: https://www.amazon.com/gp/product/B0096L2SJ0/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

    After taking it apart, it looks extremely easy to modify. I've attached some photos. I think basically all I need to do is design a 3D-Printed case, and then wire up some rechargeable batteries and a microUSB port. If anyone has suggestions on good batteries or ways to connect a microUSB port, I'd appreciate it.
     

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