12 ms·

Building a USB SNES Controller

307 points by chybby 3y ago

onli 3y ago
Of course completely awesome to make a modification like this. However, if you yourself want a USB SNES controller, consider buying one instead. 8BitDo offers them with the SN 30 Pro - the quality is good, they work with the Nintendo Switch or PC (including Linux), they have the additional buttons needed for modern games, there is a wired and a wireless version and the newer variant has afaik a replaceable battery (unlike the first). Edit: I was probably wrong about the replaceable battery, that was the 8BitDo Pro 2. Which might indeed be the better choice. Looks less like a SNES controller, but at least still has the correct button labels and core layout, see https://www.8bitdo.com/pro2/ https://www.8bitdo.com/pro2/
- edwcross 3y ago
  I did try different 8BitDo controllers, and one issue with them is the "multi-mode": in order to make them work with Android/iOS/Windows/whatever, you need to press some key before connecting them, to change the way the OS recognizes the input. Which is a deal-breaker for small children, and prevents keeping things simple (e.g. "remember to disconnect and reconnect the USB before turning the power on", e.g. when using a Raspberry Pi-based console emulator). For wireless controllers, it's even worse (extra Bluetooth mode). If only they had mechanical switches to select this behavior... You may need to keep the instructions booklet with it, just to remember which keys must be pressed before turning it on, to see which mode will be activated. The controller in TFA is more useful in this scenario, since it will always behave in the same way.
  - onli 3y ago
    Completely agree. I even had that situation myself - I misremembered how the mode switch/bluetooth pairing mode worked and was not able to connect my controller to a switch, thinking it was broken, until I realized what had happened. A small toggle switch really would be much easier. Still think it's worth it, also to not destroy an original one. On the other hand, better to modify it like this than to throw it away of course...
    - JamesSwift 3y ago
      The new version does actually use a switch instead of the magic button combination. Agreed on the previous version being annoying. Had many kid debugging sessions when they accidentally switched the mode and “broke” it.
      - 65a 3y ago
        Wireless ones have a switch, the wired ones all have the "maybe you have to hold a letter depending on the game, kernel version and OS" problem.
  - wingmanjd 3y ago
    I have four of the bluetooth SN30's for couch co-op games on my SteamDeck. I agree that if I switched between devices often (like my son's switch) I'd need a lookup table for the power-on chording. Mine have the key combinations printed onto the label on the back. Fwiw, the ones I have remember their last pairing setup, so I only need to power them back on via the "Start" button.
  - stickmangallows 3y ago
    The ones I have (SF30/SN30) remember which mode they're in so I just press the start button and it connects to my Switch. Then if I change it to bluetooth, it's the same for my Steam link until I switch it back. Plus there's a sticker on the back that gives the combos to change modes (Y+Start=Switch, X+Start=Bluetooth, etc). Some models, like the Lite 2, do have that physical mode switch.
  - deleted 3y ago
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- ludocode 3y ago
  8BitDo makes great controllers. I have an SN30 Pro, a Zero 2 and a pair of Ultimate Cs. All of them have been used extensively and they are all excellent quality. On the other hand I've had back luck with generic NES and SNES knockoff USB controllers. The quality is much worse than the originals especially in the D-Pad. It seems nobody but 8BitDo can get this right. If you stick with 8BitDo you'll have great quality but they don't necessarily match the form factor of the originals. I can see why OP would want to convert a real one.
  - onli 3y ago
    The form factor is really close though. Ignoring the added buttons, which is completely possible while gaming, it does not feel much different. https://www.onli-blogging.de/uploads/sf30pro.jpg https://www.onli-blogging.de/uploads/sf30pro.jpg for an example picture :)
- erremerre 3y ago
  Maybe if you want to play super mario, the 8bitdo sn30pro works. But it has a huge problem of false diagonals, making is absolutely worthless to play tetris, or any fighting game that requires precise control. If you need precise controls, avoid this model.
  - onli 3y ago
    I have the SF30 Pro since a few years now and there might have been different revisions, but I definitely did not observe that. And I played through Hollow Knight with it, so I doubt that the controls are imprecise - I would not have had succeeded. Granted though, neither tried Tetris nor a classical fighting game.
- Lutzb 3y ago
  There is also the 8BitDo Mod Kit for SNES/SFC Classic Edition Controller which allows to convert original SNES controllers to bluetooth. https://shop.8bitdo.com/products/8bitdo-mod-kit-for-snes-sfc-classic-edition-controller-new-edition https://shop.8bitdo.com/products/8bitdo-mod-kit-for-snes-sfc...
- 65a 3y ago
  I wish they would have proper Linux and fwupd support, which they seem to have dropped.
- mikepurvis 3y ago
  I'm using the 8BitDo wireless pads on my Switch and am very happy with them— vastly more comfortable than joycons, but a fraction of the price of the official pro controller.
- jbverschoor 3y ago
  It's not the same... It's like buying a non-nintendo controller in the past. They simply don't feel and respond the same
- patrickpkt 3y ago
  I speed run Zelda 2, though using an SNES controller. My experience with 8BitDo controllers is that they're stiffer than OEM, especially with the d-pad arrow keys. If you can use the analog inputs, they're great -- I use a Pro 2 with my Switch all the time. The d-pad, though, is a deal-breaker for classic gaming. iBuffalo used to make a controller that really did feel like OEM, but they've been out of the business for a few years.
  - bondant 3y ago
    Can only recommend the iBuffalo SNES controller too, I have two of them and they are quite good. Didn't know the brand stopped making them, it's a pity.
- deleted 3y ago
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candiddevmike 3y ago
Title should say converting a SNES controller to USB. I was thinking there would be 3D printing involved.
nkozyra 3y ago
I'm fairly novice with Arduino and interfacing with buttons/pots but I thought delays / loop interrupts were discouraged versus a reset-able counter variable?
- Goz3rr 3y ago
  They are if you have anything else that needs to be done at the same time. I would say they're fine if you have nothing else to do while waiting, or you need microsecond delays to generate a signal like in this case.
drzaiusx11 3y ago
Great write-up. Next logical step is adding Bluetooth support so you can use it on the Switch: https://www.instructables.com/DIY-ESP32-Bluetooth-GamePad-for-Android-PlayStatio/ https://www.instructables.com/DIY-ESP32-Bluetooth-GamePad-fo...
- snerbles 3y ago
  Don't forget that these controllers operate at 5V logic and the ESP32 at 3.3V. Supposedly the ESP32 can tolerate 5V inputs [0], but it's probably best to put a level shifter between the two.
snerbles 3y ago
This reminds me, years back I picked up an NTT Data Super Famicom Controller [0] with the idea of adapting it to USB. An off-the shelf USB converter only handled the standard SNES/SFC buttons and completely ignored the number pad. At the time few resources even mentioned the existence of this thing, so I put it on the shelf and promptly forgot about it for other projects. [0] https://www.raphnet.net/divers/ntt_data_sfc_controller/index_en.php https://www.raphnet.net/divers/ntt_data_sfc_controller/index...
kilpikaarna 3y ago
I've tried building an arcade stick in the past by having the Arduino emulate a keyboard and doing standard Arduino lib digitalRead of the buttons and sending keypresses (for MAME) over USB. It worked, but the lag was terrible. I wonder if this fares any better. In any case, if you can handle the wait, you can get a knockoff SNES USB pad from China for a few bucks. The plastic will feel way off, but you can probably swap over the shell from your original pad with little effort. And you'll get fresh rubber button pads, rather than 30 year old spongy ones, as a bonus. :)
- frameset 3y ago
  If you're making a home made arcade stick, check out the GP2040-CE project - https://github.com/OpenStickCommunity/GP2040-CE https://github.com/OpenStickCommunity/GP2040-CE It's got low latency and good compatibility for a bunch of platforms. Even some compatibility for PS4.
lopis 3y ago
Reminds me of that meme that says > Look What They Need to Mimic a Fraction of Our Power! That tiny arduino has a 16Mhz chip, while the NES main CPU ran at 1.66 MHz. Just a funny fact :)
- cybrox 3y ago
  I once designed a custom PCB that fits inside the original NES four score case. You can connect 4 NES controllers to it and the inputs were sent to a Raspberry Pi via UDP (so no wire between couch table and TV was needed). I think my PCB had more parts for its simple power supply than all 4 NES controllers combined. These things are an absolute masterpiece of simplicity!
  - toasteros 3y ago
    My coworker has done a similar thing, designing a PCB that allows us to connect the SNES controller over RJ45 to a custom Pi hat. We have students writing bare metal code for it!
- raldi 3y ago
  In that case, you’ll love tom7’s Reverse Emulation video: https://youtube.com/watch?v=ar9WRwCiSr0 https://youtube.com/watch?v=ar9WRwCiSr0
  - lopis 3y ago
    You're totally right. I loved it, thanks!
- tenebrisalietum 3y ago
  SNES can go up to a whopping 3.58Mhz (NTSC clock, not sure if exactly the same for PAL) but I believe due to some bus/architecture weirdness slows down to 1.79Mhz (which is what the NTSC NES runs at) when reading the controllers. Now the SuperFX chip, in Star Fox, ran at 10Mhz. Later versions like the one in Doom on SNES went up to 21Mhz.
- derefr 3y ago
al_borland 3y ago
RetroUSB has adapters for those not looking for a project. I bought one of their NES adapters years ago. https://www.retrousb.com/product_info.php?cPath=21&products_id=29&osCsid=90fc7700767cca713d0850d4621efc93 https://www.retrousb.com/product_info.php?cPath=21&products_...
- micheljansen 3y ago
  Kind of amazing that you can get a whole controller (including buttons etc.) for a fraction of the cost of an adapter. Probably a less authentic experience though: https://www.aliexpress.com/item/1005005998083106.html https://www.aliexpress.com/item/1005005998083106.html
  - creesch 3y ago
    Controllers that cheap generally are made of terrible creeky plastic, mushy buttons and generally poor assembly. You can get decent retro styled USB controllers, but they will be a bit more expensive than this one.
    - TheCleric 3y ago
      Yeah I love the 8bitdo ones. But they're not inexpensive.
      - JamesSwift 3y ago
        People are always surprised that the controllers are the largest line item when building a retropie. You really want quality though, they make a big difference in that the dpads and the thumb sticks are both good.
  - al_borland 3y ago
    I picked up my NES controllers at Goodwill. Super cheap and the real thing.
- TillE 3y ago
  Raphnet adapters (designed by one guy in Canada) are the most popular option among serious speedrunners, if you want minimum latency. Their equivalent product is currently out of stock: https://www.raphnet-tech.com/products/snes2usb_1player_adapter_v2/index.php https://www.raphnet-tech.com/products/snes2usb_1player_adapt...
Grazester 3y ago
Before the existence of Blue Retro or any commerically available adapter, I wanted to use Playstation 4 Dual Shock wireless controllers with my Sega Saturn as an analog controller. I used the Arduino USB Shield Adapter since that supported wireless Dual Shock controller and all I needed to handle was the Saturn side of things with emulating a controller protocol so the Saturn things it had a 3D controller plugged into it. This was my introduction to Arduino programming, bitmasks and direct port manipulation. I have changed the recently to not use direct port manipulation since it really isn't need for the Saturn and I wanted to make the code more portable. I have since made a wireless for the official 3D controllers for the Saturn with no noticeable latency. Something it seems is still taking others a while to figure out it. I am not doing anything fancy so I don't know how they can't figure that out yet. They are using Blue Retro though where as I am just using an nRF24L01. So maybe the Blue Retro is adding some unnecessary over head. This i have not released the source for though.
spintin 3y ago
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- bonzini 3y ago
  I did the same but went for an ESP-8266 to connect over WiFi (using UDP). https://github.com/bonzini/wcc https://github.com/bonzini/wcc contains both the Arduino sketch and the client that runs under Linux to present a virtual input device.
amenghra 3y ago
You could put all the logic in the USB connector and then not have to modify the shell. See eg the OMG cable: https://mg.lol/blog/ https://mg.lol/blog/
MarkusWandel 3y ago
I did something similar by cutting down the PCB of a standard Microsoft game controller and wiring it into an old Wico Command Control joystick (the only thing I kept when I gave away all my C64 stuff - before it became collectible). https://wandel.ca/pic.cgi?49ceb103 https://wandel.ca/pic.cgi?49ceb103 Totally authentic for playing old C64 games in an emulator. But these days, I'd leave the joystick alone and just use an Arduino to do a DB9 to USB translator.
crote 3y ago
Looking at the described protocol it seems the SNES controller uses a simple 16-bit parallel-in-serial-out shift register - and a quick Google confirmed that. This means the timing is almost certainly quite loose, and there's a pretty decent chance you might even be able to poll it as the 1kHz "needed" for "serious" gaming. And it'd be pretty trivial to offload the readout to the MCU's SPI peripheral.
- toasteros 3y ago
  It's extremely loose! Using a custom PCB to connect the controller over RJ45 to a custom Pi hat I wrote some code to simply display the button presses on screen, to test the functionality of the controller (we are modifying hundreds). I had to play around a lot with the timings to match up the response of the program with the speed of my finger pushing a button, else the program would return "you pushed B" a dozen times on a single push. I do wonder how much original SNES devs had to consider similar scenarios.
  - 65a 3y ago
    The physical switches may actually bounce, so you might need some debounce logic, if it wasn't the shift register glitching out. It's pretty common for buttons to need this, often seen in keyboard firmware as well for similar reasons, the physical mechanism actually will oscillate a bit between states.
    - snitty 3y ago
      The way the NES and SNES work is that once per frame you read from the memory address mapped to the shift register to get all the bits out, one at a time. For certain inputs you only care if it's pressed now. Others you compare to previous state to see if it changed. Bounce could, theoretically, cause an input to be read as a non-input if it just bounced at exactly the wrong time, but it won't cause multiple inputs, as it's only polled every 1/60th of a second.
      - 65a 3y ago
jareklupinski 3y ago
my very first electronics projects were classic controller to USB conversions. I remember struggling with PIC after just wrapping my head around BASIC Stamps, and trying to follow raphnet tutorials https://www.raphnet.net/electronique/multiuse_tiny1/index_en.php https://www.raphnet.net/electronique/multiuse_tiny1/index_en... going to show this article when people ask 'how do i get started with a fun electronics project' :)
- chybby 3y ago
  Thank you! Glad you liked it :)
itslennysfault 3y ago
This is AWESOME. I set out to do exactly this like a decade ago and couldn't figure out how. I still have the two SNES controllers in my electronics box and dozens of Arduinos. Looks like I'll be making some USB SNES controllers this weekend.
- chybby 3y ago
  Have fun!
mfonda 3y ago
This brings back memories. The first (and only) hardware project I've ever done is building a 4-controller multitap that connected via parallel port. It ended up working really well--lots of fun playing games on snes9x with friends.
r0bbbo 3y ago
Are there any implications of the polling rate not quite aligning as the original controller would've?
- jerf 3y ago
  If for the sake of argument we are plugging this into an SNES emulator running at 60Hz, then the stack between the USB gamepad and the emulator already has to handle that the gamepad is not rigidly synced to the emulated SNES and will presumably take every input from the gamepad and use it as the emulated input to the SNES next time it asks, unless a new one comes in first. At slightly faster than 60Hz, the net effect will be that the delay between input and having an effect on the SNES will wander about 1/60th of a second over time, as the sync varies, and every once in a while a particular input will be overwritten before it makes it into the emulator. It may be very difficult to perceive this, though, due to other delays already built into such a set up. On a real SNES, it would be right on the edge of perception anyhow. Being very close to the poll rate but not quite there is probably near the theoretically worst case. It would probably be much better to poll at 240+Hz, cutting the latency between input to a consistent 1/4ish of a frame. However, I doubt this improvement could be "felt" by very many people at all.
  - deleted 3y ago
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- armada651 3y ago
  Yeah I too wondered why the author would target 60Hz at all. The fact that the SNES controller is polled at 60Hz is simply a consequence of the game reading the input at that rate. As mentioned in the other comment in this setup the polling of the controller is not in sync with the game reading the input at all. Thus even if you target a polling rate of 60Hz perfectly you'd actually have worse input latency than the original hardware. It would be much better to target 120Hz or higher to reduce input latency and bring it as close to the original hardware as possible by ensuring there is always an up-to-date input state ready for the game to read.
  - 3y ago
xg15 3y ago
This is really cool! One thing I'm wondering is how the SNES implemented its Multitap support[1] with such a simple "wire protocol". Could it be that the two missing wires and/or 4 unused slots in the polling cycle are used for some kind of adressing scheme when a multitap is plugged in? https://nintendo.fandom.com/wiki/Super_Multitap https://nintendo.fandom.com/wiki/Super_Multitap
- ooterness 3y ago
  RGMX has a video series on a lot of the low-level SNES functions. If you've ever wanted to know how Mode-7 works, it's great. The video below goes over the controllers, Super Scope, mouse, etc. A brief discussion of the multi-tap starts around 16:00. You are correct that it leverages the spare pins. https://www.youtube.com/watch?v=2Dw7NFm1ZfY https://www.youtube.com/watch?v=2Dw7NFm1ZfY
- wharvle 3y ago
  The NES also had “multitaps”. One model was wired (the “Four Score”), the other was wireless (battery powered; the “Satellite”) with an IR receiver unit that plugged into both controller ports. The IR wireless one was, in my experience (it was the only one I had) far less janky and failure-prone than one might suppose. Actually worked quite well.
- dougg3 3y ago
  The schematics for the multitap are out there in the SNES developer manual [1]. I actually made one on a breadboard for fun [2] and eventually turned it into a PCB. It's a pretty simple circuit with an analog mux and some tri-state buffers. [1] https://archive.org/details/SNESDevManual/book2/page/n385/mode/2up https://archive.org/details/SNESDevManual/book2/page/n385/mo... [2] https://www.downtowndougbrown.com/2013/04/homebrew-snes-4-player-multitap-adapter/ https://www.downtowndougbrown.com/2013/04/homebrew-snes-4-pl...
hellweaver666 3y ago
I bet you could build something like this with a Seeeduino Xiao (or Adafruit QTPY) to get a smaller footprint inside the case and not need to modify the plastic.
hellweaver666 3y ago
I once modified a SNES controller and put a whole Raspberry Pi Zero, battery and boost/charger board inside for a portable retropie setup.
- wayvey 3y ago
  Wow, that would be incredible! Did you document the project at all? I'd love to know more and maybe attempt something similar.
  - hellweaver666 3y ago
    I just followed this guide. It’s pretty straightforward! https://hackaday.io/project/16288/instructions https://hackaday.io/project/16288/instructions
hackan 3y ago
I built a gamepad port snes adapter a decade ago, 10/10 would do this :ok_hand:
- rrr_oh_man 3y ago
  :thumbs_up:
patrickpkt 3y ago
The Daemonbite project (https://github.com/MickGyver/DaemonBite-Retro-Controllers-USB https://github.com/MickGyver/DaemonBite-Retro-Controllers-US...) does essentially the same thing, but works like a normal USB controller from the perspective of the host. I've used one with a MiSTer FPGA setup and it's almost indistinguishable from a native SNES controller in terms of response. For my build, I cut a cheap controller extension cord in half, avoiding the need to actually modify the controller itself.
daneel_w 3y ago
These, as well as NES dittos, were all over eBay and AliExpress for $3 a piece some 10 years ago. Probably still are. I've got one of each, just to get the right feeling when playing Zelda 1 and Pocky & Rocky on emulators.
deleted 3y ago
[deleted]
jdelman 3y ago
Is Arduino real-time? I.e. is a 6 millisecond delay guaranteed to actually be 6 milliseconds?
- AYoung010 3y ago
  Largely, yes. Arduino code runs on bare metal, and delays simply block execution so they should be accurate with some constant overhead.
- mcpherrinm 3y ago
  The Arduino is a single-threaded microcontroller running a single code loop, plus interrupts. delayMicroseconds is a busy-wait loop, so is relatively precise (to within a few instruction's execution time. However, interrupts can happen during that sleep, and the time spent handling interrupts won't be accounted for properly. It isn't a real real-time system, but for a project like this, it'll be good enough.
- vvoid 3y ago
  Yes, it is real time, but due to interrupts you have to manage critical sections with cli() and sei() and your time base is a 16.000 MHz crystal. Most instructions for ATmega and ATtiny execute in 1 clock cycle so writing deterministic, time-critical code is straightforward.
  - chybby 3y ago
    Thanks for the tip to turn off interrupts when working with precise timing!
allenu 3y ago
Controllers are surprisingly super easy to work with and a good gateway to some basic electronics hacking. I've actually gone the opposite direction from this post. I have a Neo Geo arcade board (JAMMA) and it has plugs for Neo Geo controllers (as in the controllers for the console version of the Neo Geo). I wanted to use the Neo Geo without plugging it into an arcade cabinet, so I got a "Supergun" board to play it on an RGB monitor. However, I didn't have a controller for it. I noticed that there was an emulator-based "Neo Geo X" system out in the wild and you could purchase a controller accessory on its own, so I got one, not realizing it was purely a USB controller in the shape of the original Neo Geo ones, but no problem. I bought a Neo Geo controller cable and just desoldered the button to USB connections inside the controller and connected them directly to the Neo Geo controller cable. Worked like a charm!
- vikingerik 3y ago
  And I'll add my controller hacking as well: https://imgur.com/a/Mu43dqg https://imgur.com/a/Mu43dqg As a poor college student, I home-built a dance pad for Dance Dance Revolution, out of wood and foil and by soldering the connections into a controller. Worked perfectly!
  - allenu 3y ago
    Well done and good job using what looks like a cheap controller and aluminum foil to keep costs down. :)
  - rahimnathwani 3y ago
    I love this. It probably worked better than a cheap 'soft' pad.
    - RockRobotRock 3y ago
      Yes! Soft pads are the worst.
- ansible 3y ago
  Yes. I got my start, back in the day, following along a magazine article on modifying an Atari 2600 joystick for use with the Tandy Color computer. Worked fairly well too, though I ended up modifying my Galaxian arcade game clone to work with it.
kalium-xyz 3y ago
Ive done this with the attiny85 based digisparks for various controllers. Can recommend. It has very little IO though which can be an issue
makapuf 3y ago
I think the project is cool, but since a usb snes controller is, what 5$ on ebay (or more to have quality one), I find it too bad that you damage a working, vintage real snes controller that there will be less and less of.
- chybby 3y ago
  The way I saw it, I'd rather have a memento of the past that I can actually use than one that will sit around in a drawer.
  - makapuf 3y ago
    With an adapter you still can use the controller (or you can also use a snes)
MarioMan 3y ago
I prefer a nondestructive approach. I set up an ATTINY85 clone to serve as a DIY USB adapter. Just solder a controller extension cable to the microcontroller to donate the right port, and you have everything you need. You have enough GPIO pins and the requisite 5v logic to make it a great fit. Mine was made for NES controllers, but it uses the same shift logic as the SNES controller, just with fewer buttons.
pipes 3y ago
Not sure if this has been mentioned already: https://github.com/MickGyver/DaemonBite-Retro-Controllers-USB https://github.com/MickGyver/DaemonBite-Retro-Controllers-US... It's how to build your own demon bite adapters using Arduino, for various console. These are super low lag. If you Google demon bite you can find various sites selling premade adapters. These are really popular with mister fpga users: https://en.m.wikipedia.org/wiki/MiSTer https://en.m.wikipedia.org/wiki/MiSTer This is a bit of a rabbit hole, the mister is the best retro related thing I've bought / built. Here's a useful listing of various usb adapters and their latency: https://rpubs.com/misteraddons/inputlatency https://rpubs.com/misteraddons/inputlatency
8A51C 3y ago
I recently made an xbox 360 chatpad work with windows using an esp32. It's kind of a grail moment when you search about it. A bit late to the party as the modern chatpad + controller do work, but 360 controllers and chatpads are very inexpensive. It's chatpad > esp32 > bluetooth > anything, stuck neatly on the back you hardly notice it's there.

307 points by chybby 3y ago

onli 3y ago

Of course completely awesome to make a modification like this. However, if you yourself want a USB SNES controller, consider buying one instead. 8BitDo offers them with the SN 30 Pro - the quality is good, they work with the Nintendo Switch or PC (including Linux), they have the additional buttons needed for modern games, there is a wired and a wireless version and the newer variant has afaik a replaceable battery (unlike the first). Edit: I was probably wrong about the replaceable battery, that was the 8BitDo Pro 2. Which might indeed be the better choice. Looks less like a SNES controller, but at least still has the correct button labels and core layout, see https://www.8bitdo.com/pro2/ https://www.8bitdo.com/pro2/

edwcross 3y ago
I did try different 8BitDo controllers, and one issue with them is the "multi-mode": in order to make them work with Android/iOS/Windows/whatever, you need to press some key before connecting them, to change the way the OS recognizes the input. Which is a deal-breaker for small children, and prevents keeping things simple (e.g. "remember to disconnect and reconnect the USB before turning the power on", e.g. when using a Raspberry Pi-based console emulator). For wireless controllers, it's even worse (extra Bluetooth mode). If only they had mechanical switches to select this behavior... You may need to keep the instructions booklet with it, just to remember which keys must be pressed before turning it on, to see which mode will be activated. The controller in TFA is more useful in this scenario, since it will always behave in the same way.
- onli 3y ago
  Completely agree. I even had that situation myself - I misremembered how the mode switch/bluetooth pairing mode worked and was not able to connect my controller to a switch, thinking it was broken, until I realized what had happened. A small toggle switch really would be much easier. Still think it's worth it, also to not destroy an original one. On the other hand, better to modify it like this than to throw it away of course...
  - JamesSwift 3y ago
    The new version does actually use a switch instead of the magic button combination. Agreed on the previous version being annoying. Had many kid debugging sessions when they accidentally switched the mode and “broke” it.
    - 65a 3y ago
      Wireless ones have a switch, the wired ones all have the "maybe you have to hold a letter depending on the game, kernel version and OS" problem.
- wingmanjd 3y ago
  I have four of the bluetooth SN30's for couch co-op games on my SteamDeck. I agree that if I switched between devices often (like my son's switch) I'd need a lookup table for the power-on chording. Mine have the key combinations printed onto the label on the back. Fwiw, the ones I have remember their last pairing setup, so I only need to power them back on via the "Start" button.
- stickmangallows 3y ago
  The ones I have (SF30/SN30) remember which mode they're in so I just press the start button and it connects to my Switch. Then if I change it to bluetooth, it's the same for my Steam link until I switch it back. Plus there's a sticker on the back that gives the combos to change modes (Y+Start=Switch, X+Start=Bluetooth, etc). Some models, like the Lite 2, do have that physical mode switch.
- deleted 3y ago
  [deleted]
ludocode 3y ago
8BitDo makes great controllers. I have an SN30 Pro, a Zero 2 and a pair of Ultimate Cs. All of them have been used extensively and they are all excellent quality. On the other hand I've had back luck with generic NES and SNES knockoff USB controllers. The quality is much worse than the originals especially in the D-Pad. It seems nobody but 8BitDo can get this right. If you stick with 8BitDo you'll have great quality but they don't necessarily match the form factor of the originals. I can see why OP would want to convert a real one.
- onli 3y ago
  The form factor is really close though. Ignoring the added buttons, which is completely possible while gaming, it does not feel much different. https://www.onli-blogging.de/uploads/sf30pro.jpg https://www.onli-blogging.de/uploads/sf30pro.jpg for an example picture :)
erremerre 3y ago
Maybe if you want to play super mario, the 8bitdo sn30pro works. But it has a huge problem of false diagonals, making is absolutely worthless to play tetris, or any fighting game that requires precise control. If you need precise controls, avoid this model.
- onli 3y ago
  I have the SF30 Pro since a few years now and there might have been different revisions, but I definitely did not observe that. And I played through Hollow Knight with it, so I doubt that the controls are imprecise - I would not have had succeeded. Granted though, neither tried Tetris nor a classical fighting game.
Lutzb 3y ago
There is also the 8BitDo Mod Kit for SNES/SFC Classic Edition Controller which allows to convert original SNES controllers to bluetooth. https://shop.8bitdo.com/products/8bitdo-mod-kit-for-snes-sfc-classic-edition-controller-new-edition https://shop.8bitdo.com/products/8bitdo-mod-kit-for-snes-sfc...
65a 3y ago
I wish they would have proper Linux and fwupd support, which they seem to have dropped.
mikepurvis 3y ago
I'm using the 8BitDo wireless pads on my Switch and am very happy with them— vastly more comfortable than joycons, but a fraction of the price of the official pro controller.
jbverschoor 3y ago
It's not the same... It's like buying a non-nintendo controller in the past. They simply don't feel and respond the same
patrickpkt 3y ago
I speed run Zelda 2, though using an SNES controller. My experience with 8BitDo controllers is that they're stiffer than OEM, especially with the d-pad arrow keys. If you can use the analog inputs, they're great -- I use a Pro 2 with my Switch all the time. The d-pad, though, is a deal-breaker for classic gaming. iBuffalo used to make a controller that really did feel like OEM, but they've been out of the business for a few years.
- bondant 3y ago
  Can only recommend the iBuffalo SNES controller too, I have two of them and they are quite good. Didn't know the brand stopped making them, it's a pity.
deleted 3y ago
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candiddevmike 3y ago

Title should say converting a SNES controller to USB. I was thinking there would be 3D printing involved.

nkozyra 3y ago

I'm fairly novice with Arduino and interfacing with buttons/pots but I thought delays / loop interrupts were discouraged versus a reset-able counter variable?

Goz3rr 3y ago
They are if you have anything else that needs to be done at the same time. I would say they're fine if you have nothing else to do while waiting, or you need microsecond delays to generate a signal like in this case.

drzaiusx11 3y ago

Great write-up. Next logical step is adding Bluetooth support so you can use it on the Switch: https://www.instructables.com/DIY-ESP32-Bluetooth-GamePad-for-Android-PlayStatio/ https://www.instructables.com/DIY-ESP32-Bluetooth-GamePad-fo...

snerbles 3y ago
Don't forget that these controllers operate at 5V logic and the ESP32 at 3.3V. Supposedly the ESP32 can tolerate 5V inputs [0], but it's probably best to put a level shifter between the two.

snerbles 3y ago

This reminds me, years back I picked up an NTT Data Super Famicom Controller [0] with the idea of adapting it to USB. An off-the shelf USB converter only handled the standard SNES/SFC buttons and completely ignored the number pad. At the time few resources even mentioned the existence of this thing, so I put it on the shelf and promptly forgot about it for other projects. [0] https://www.raphnet.net/divers/ntt_data_sfc_controller/index_en.php https://www.raphnet.net/divers/ntt_data_sfc_controller/index...

kilpikaarna 3y ago

I've tried building an arcade stick in the past by having the Arduino emulate a keyboard and doing standard Arduino lib digitalRead of the buttons and sending keypresses (for MAME) over USB. It worked, but the lag was terrible. I wonder if this fares any better. In any case, if you can handle the wait, you can get a knockoff SNES USB pad from China for a few bucks. The plastic will feel way off, but you can probably swap over the shell from your original pad with little effort. And you'll get fresh rubber button pads, rather than 30 year old spongy ones, as a bonus. :)

frameset 3y ago
If you're making a home made arcade stick, check out the GP2040-CE project - https://github.com/OpenStickCommunity/GP2040-CE https://github.com/OpenStickCommunity/GP2040-CE It's got low latency and good compatibility for a bunch of platforms. Even some compatibility for PS4.

lopis 3y ago

Reminds me of that meme that says > Look What They Need to Mimic a Fraction of Our Power! That tiny arduino has a 16Mhz chip, while the NES main CPU ran at 1.66 MHz. Just a funny fact :)

cybrox 3y ago
I once designed a custom PCB that fits inside the original NES four score case. You can connect 4 NES controllers to it and the inputs were sent to a Raspberry Pi via UDP (so no wire between couch table and TV was needed). I think my PCB had more parts for its simple power supply than all 4 NES controllers combined. These things are an absolute masterpiece of simplicity!
- toasteros 3y ago
  My coworker has done a similar thing, designing a PCB that allows us to connect the SNES controller over RJ45 to a custom Pi hat. We have students writing bare metal code for it!
raldi 3y ago
In that case, you’ll love tom7’s Reverse Emulation video: https://youtube.com/watch?v=ar9WRwCiSr0 https://youtube.com/watch?v=ar9WRwCiSr0
- lopis 3y ago
  You're totally right. I loved it, thanks!
tenebrisalietum 3y ago
SNES can go up to a whopping 3.58Mhz (NTSC clock, not sure if exactly the same for PAL) but I believe due to some bus/architecture weirdness slows down to 1.79Mhz (which is what the NTSC NES runs at) when reading the controllers. Now the SuperFX chip, in Star Fox, ran at 10Mhz. Later versions like the one in Doom on SNES went up to 21Mhz.
derefr 3y ago

al_borland 3y ago

RetroUSB has adapters for those not looking for a project. I bought one of their NES adapters years ago. https://www.retrousb.com/product_info.php?cPath=21&products_id=29&osCsid=90fc7700767cca713d0850d4621efc93 https://www.retrousb.com/product_info.php?cPath=21&products_...

micheljansen 3y ago
Kind of amazing that you can get a whole controller (including buttons etc.) for a fraction of the cost of an adapter. Probably a less authentic experience though: https://www.aliexpress.com/item/1005005998083106.html https://www.aliexpress.com/item/1005005998083106.html
- creesch 3y ago
  Controllers that cheap generally are made of terrible creeky plastic, mushy buttons and generally poor assembly. You can get decent retro styled USB controllers, but they will be a bit more expensive than this one.
  - TheCleric 3y ago
    Yeah I love the 8bitdo ones. But they're not inexpensive.
    - JamesSwift 3y ago
      People are always surprised that the controllers are the largest line item when building a retropie. You really want quality though, they make a big difference in that the dpads and the thumb sticks are both good.
- al_borland 3y ago
  I picked up my NES controllers at Goodwill. Super cheap and the real thing.
TillE 3y ago
Raphnet adapters (designed by one guy in Canada) are the most popular option among serious speedrunners, if you want minimum latency. Their equivalent product is currently out of stock: https://www.raphnet-tech.com/products/snes2usb_1player_adapter_v2/index.php https://www.raphnet-tech.com/products/snes2usb_1player_adapt...

Grazester 3y ago

Before the existence of Blue Retro or any commerically available adapter, I wanted to use Playstation 4 Dual Shock wireless controllers with my Sega Saturn as an analog controller. I used the Arduino USB Shield Adapter since that supported wireless Dual Shock controller and all I needed to handle was the Saturn side of things with emulating a controller protocol so the Saturn things it had a 3D controller plugged into it. This was my introduction to Arduino programming, bitmasks and direct port manipulation. I have changed the recently to not use direct port manipulation since it really isn't need for the Saturn and I wanted to make the code more portable. I have since made a wireless for the official 3D controllers for the Saturn with no noticeable latency. Something it seems is still taking others a while to figure out it. I am not doing anything fancy so I don't know how they can't figure that out yet. They are using Blue Retro though where as I am just using an nRF24L01. So maybe the Blue Retro is adding some unnecessary over head. This i have not released the source for though.

spintin 3y ago

[dead]

bonzini 3y ago
I did the same but went for an ESP-8266 to connect over WiFi (using UDP). https://github.com/bonzini/wcc https://github.com/bonzini/wcc contains both the Arduino sketch and the client that runs under Linux to present a virtual input device.

amenghra 3y ago

You could put all the logic in the USB connector and then not have to modify the shell. See eg the OMG cable: https://mg.lol/blog/ https://mg.lol/blog/

MarkusWandel 3y ago

I did something similar by cutting down the PCB of a standard Microsoft game controller and wiring it into an old Wico Command Control joystick (the only thing I kept when I gave away all my C64 stuff - before it became collectible). https://wandel.ca/pic.cgi?49ceb103 https://wandel.ca/pic.cgi?49ceb103 Totally authentic for playing old C64 games in an emulator. But these days, I'd leave the joystick alone and just use an Arduino to do a DB9 to USB translator.

crote 3y ago

Looking at the described protocol it seems the SNES controller uses a simple 16-bit parallel-in-serial-out shift register - and a quick Google confirmed that. This means the timing is almost certainly quite loose, and there's a pretty decent chance you might even be able to poll it as the 1kHz "needed" for "serious" gaming. And it'd be pretty trivial to offload the readout to the MCU's SPI peripheral.

toasteros 3y ago
It's extremely loose! Using a custom PCB to connect the controller over RJ45 to a custom Pi hat I wrote some code to simply display the button presses on screen, to test the functionality of the controller (we are modifying hundreds). I had to play around a lot with the timings to match up the response of the program with the speed of my finger pushing a button, else the program would return "you pushed B" a dozen times on a single push. I do wonder how much original SNES devs had to consider similar scenarios.
- 65a 3y ago
  The physical switches may actually bounce, so you might need some debounce logic, if it wasn't the shift register glitching out. It's pretty common for buttons to need this, often seen in keyboard firmware as well for similar reasons, the physical mechanism actually will oscillate a bit between states.
  - snitty 3y ago
    The way the NES and SNES work is that once per frame you read from the memory address mapped to the shift register to get all the bits out, one at a time. For certain inputs you only care if it's pressed now. Others you compare to previous state to see if it changed. Bounce could, theoretically, cause an input to be read as a non-input if it just bounced at exactly the wrong time, but it won't cause multiple inputs, as it's only polled every 1/60th of a second.
    - 65a 3y ago

jareklupinski 3y ago

my very first electronics projects were classic controller to USB conversions. I remember struggling with PIC after just wrapping my head around BASIC Stamps, and trying to follow raphnet tutorials https://www.raphnet.net/electronique/multiuse_tiny1/index_en.php https://www.raphnet.net/electronique/multiuse_tiny1/index_en... going to show this article when people ask 'how do i get started with a fun electronics project' :)

chybby 3y ago
Thank you! Glad you liked it :)

itslennysfault 3y ago

This is AWESOME. I set out to do exactly this like a decade ago and couldn't figure out how. I still have the two SNES controllers in my electronics box and dozens of Arduinos. Looks like I'll be making some USB SNES controllers this weekend.

chybby 3y ago
Have fun!

mfonda 3y ago

This brings back memories. The first (and only) hardware project I've ever done is building a 4-controller multitap that connected via parallel port. It ended up working really well--lots of fun playing games on snes9x with friends.

r0bbbo 3y ago

Are there any implications of the polling rate not quite aligning as the original controller would've?

jerf 3y ago
If for the sake of argument we are plugging this into an SNES emulator running at 60Hz, then the stack between the USB gamepad and the emulator already has to handle that the gamepad is not rigidly synced to the emulated SNES and will presumably take every input from the gamepad and use it as the emulated input to the SNES next time it asks, unless a new one comes in first. At slightly faster than 60Hz, the net effect will be that the delay between input and having an effect on the SNES will wander about 1/60th of a second over time, as the sync varies, and every once in a while a particular input will be overwritten before it makes it into the emulator. It may be very difficult to perceive this, though, due to other delays already built into such a set up. On a real SNES, it would be right on the edge of perception anyhow. Being very close to the poll rate but not quite there is probably near the theoretically worst case. It would probably be much better to poll at 240+Hz, cutting the latency between input to a consistent 1/4ish of a frame. However, I doubt this improvement could be "felt" by very many people at all.
- deleted 3y ago
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armada651 3y ago
Yeah I too wondered why the author would target 60Hz at all. The fact that the SNES controller is polled at 60Hz is simply a consequence of the game reading the input at that rate. As mentioned in the other comment in this setup the polling of the controller is not in sync with the game reading the input at all. Thus even if you target a polling rate of 60Hz perfectly you'd actually have worse input latency than the original hardware. It would be much better to target 120Hz or higher to reduce input latency and bring it as close to the original hardware as possible by ensuring there is always an up-to-date input state ready for the game to read.
- 3y ago

xg15 3y ago

This is really cool! One thing I'm wondering is how the SNES implemented its Multitap support[1] with such a simple "wire protocol". Could it be that the two missing wires and/or 4 unused slots in the polling cycle are used for some kind of adressing scheme when a multitap is plugged in? https://nintendo.fandom.com/wiki/Super_Multitap https://nintendo.fandom.com/wiki/Super_Multitap

ooterness 3y ago
RGMX has a video series on a lot of the low-level SNES functions. If you've ever wanted to know how Mode-7 works, it's great. The video below goes over the controllers, Super Scope, mouse, etc. A brief discussion of the multi-tap starts around 16:00. You are correct that it leverages the spare pins. https://www.youtube.com/watch?v=2Dw7NFm1ZfY https://www.youtube.com/watch?v=2Dw7NFm1ZfY
wharvle 3y ago
The NES also had “multitaps”. One model was wired (the “Four Score”), the other was wireless (battery powered; the “Satellite”) with an IR receiver unit that plugged into both controller ports. The IR wireless one was, in my experience (it was the only one I had) far less janky and failure-prone than one might suppose. Actually worked quite well.
dougg3 3y ago
The schematics for the multitap are out there in the SNES developer manual [1]. I actually made one on a breadboard for fun [2] and eventually turned it into a PCB. It's a pretty simple circuit with an analog mux and some tri-state buffers. [1] https://archive.org/details/SNESDevManual/book2/page/n385/mode/2up https://archive.org/details/SNESDevManual/book2/page/n385/mo... [2] https://www.downtowndougbrown.com/2013/04/homebrew-snes-4-player-multitap-adapter/ https://www.downtowndougbrown.com/2013/04/homebrew-snes-4-pl...

hellweaver666 3y ago

I bet you could build something like this with a Seeeduino Xiao (or Adafruit QTPY) to get a smaller footprint inside the case and not need to modify the plastic.

hellweaver666 3y ago

I once modified a SNES controller and put a whole Raspberry Pi Zero, battery and boost/charger board inside for a portable retropie setup.

wayvey 3y ago
Wow, that would be incredible! Did you document the project at all? I'd love to know more and maybe attempt something similar.
- hellweaver666 3y ago
  I just followed this guide. It’s pretty straightforward! https://hackaday.io/project/16288/instructions https://hackaday.io/project/16288/instructions

hackan 3y ago

I built a gamepad port snes adapter a decade ago, 10/10 would do this :ok_hand:

rrr_oh_man 3y ago
:thumbs_up:

patrickpkt 3y ago

The Daemonbite project (https://github.com/MickGyver/DaemonBite-Retro-Controllers-USB https://github.com/MickGyver/DaemonBite-Retro-Controllers-US...) does essentially the same thing, but works like a normal USB controller from the perspective of the host. I've used one with a MiSTer FPGA setup and it's almost indistinguishable from a native SNES controller in terms of response. For my build, I cut a cheap controller extension cord in half, avoiding the need to actually modify the controller itself.

daneel_w 3y ago

These, as well as NES dittos, were all over eBay and AliExpress for $3 a piece some 10 years ago. Probably still are. I've got one of each, just to get the right feeling when playing Zelda 1 and Pocky & Rocky on emulators.

deleted 3y ago

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jdelman 3y ago

Is Arduino real-time? I.e. is a 6 millisecond delay guaranteed to actually be 6 milliseconds?

AYoung010 3y ago
Largely, yes. Arduino code runs on bare metal, and delays simply block execution so they should be accurate with some constant overhead.
mcpherrinm 3y ago
The Arduino is a single-threaded microcontroller running a single code loop, plus interrupts. delayMicroseconds is a busy-wait loop, so is relatively precise (to within a few instruction's execution time. However, interrupts can happen during that sleep, and the time spent handling interrupts won't be accounted for properly. It isn't a real real-time system, but for a project like this, it'll be good enough.
vvoid 3y ago
Yes, it is real time, but due to interrupts you have to manage critical sections with cli() and sei() and your time base is a 16.000 MHz crystal. Most instructions for ATmega and ATtiny execute in 1 clock cycle so writing deterministic, time-critical code is straightforward.
- chybby 3y ago
  Thanks for the tip to turn off interrupts when working with precise timing!

allenu 3y ago

Controllers are surprisingly super easy to work with and a good gateway to some basic electronics hacking. I've actually gone the opposite direction from this post. I have a Neo Geo arcade board (JAMMA) and it has plugs for Neo Geo controllers (as in the controllers for the console version of the Neo Geo). I wanted to use the Neo Geo without plugging it into an arcade cabinet, so I got a "Supergun" board to play it on an RGB monitor. However, I didn't have a controller for it. I noticed that there was an emulator-based "Neo Geo X" system out in the wild and you could purchase a controller accessory on its own, so I got one, not realizing it was purely a USB controller in the shape of the original Neo Geo ones, but no problem. I bought a Neo Geo controller cable and just desoldered the button to USB connections inside the controller and connected them directly to the Neo Geo controller cable. Worked like a charm!

vikingerik 3y ago
And I'll add my controller hacking as well: https://imgur.com/a/Mu43dqg https://imgur.com/a/Mu43dqg As a poor college student, I home-built a dance pad for Dance Dance Revolution, out of wood and foil and by soldering the connections into a controller. Worked perfectly!
- allenu 3y ago
  Well done and good job using what looks like a cheap controller and aluminum foil to keep costs down. :)
- rahimnathwani 3y ago
  I love this. It probably worked better than a cheap 'soft' pad.
  - RockRobotRock 3y ago
    Yes! Soft pads are the worst.
ansible 3y ago
Yes. I got my start, back in the day, following along a magazine article on modifying an Atari 2600 joystick for use with the Tandy Color computer. Worked fairly well too, though I ended up modifying my Galaxian arcade game clone to work with it.

kalium-xyz 3y ago

Ive done this with the attiny85 based digisparks for various controllers. Can recommend. It has very little IO though which can be an issue

makapuf 3y ago

I think the project is cool, but since a usb snes controller is, what 5$ on ebay (or more to have quality one), I find it too bad that you damage a working, vintage real snes controller that there will be less and less of.

chybby 3y ago
The way I saw it, I'd rather have a memento of the past that I can actually use than one that will sit around in a drawer.
- makapuf 3y ago
  With an adapter you still can use the controller (or you can also use a snes)

MarioMan 3y ago

I prefer a nondestructive approach. I set up an ATTINY85 clone to serve as a DIY USB adapter. Just solder a controller extension cable to the microcontroller to donate the right port, and you have everything you need. You have enough GPIO pins and the requisite 5v logic to make it a great fit. Mine was made for NES controllers, but it uses the same shift logic as the SNES controller, just with fewer buttons.

pipes 3y ago

Not sure if this has been mentioned already: https://github.com/MickGyver/DaemonBite-Retro-Controllers-USB https://github.com/MickGyver/DaemonBite-Retro-Controllers-US... It's how to build your own demon bite adapters using Arduino, for various console. These are super low lag. If you Google demon bite you can find various sites selling premade adapters. These are really popular with mister fpga users: https://en.m.wikipedia.org/wiki/MiSTer https://en.m.wikipedia.org/wiki/MiSTer This is a bit of a rabbit hole, the mister is the best retro related thing I've bought / built. Here's a useful listing of various usb adapters and their latency: https://rpubs.com/misteraddons/inputlatency https://rpubs.com/misteraddons/inputlatency

8A51C 3y ago

I recently made an xbox 360 chatpad work with windows using an esp32. It's kind of a grail moment when you search about it. A bit late to the party as the modern chatpad + controller do work, but 360 controllers and chatpads are very inexpensive. It's chatpad > esp32 > bluetooth > anything, stuck neatly on the back you hardly notice it's there.