cjd280's Solderless External Nintendo Switch Fusee Dongle

Hey, I figured I'd throw these insturctions together along with part list and some pictures. I just made a dongle for pretty cheap using some open source code, and wanted to share.

Its pretty bare bones, kidna ugly, and has no case. But its cheap and easy. I'll probably try and make something to put it in someday, but I don't have a 3d printer. I've included links to everything on Adafruit and Amazon for other parts. Don't worry, they aren't affilate links =)


Overall, this is pretty cheap and easy to put together. The main parts are from Adafruit, and a few cables/adaptor I already had.

  1. Main Board: Adafruit Gemma m0 which can be purchased here: http://adafru.it/3501
  2. Power Supply: 2 x 2032 Coin Cell Battery which can be purchased here: http://adafru.it/783
  3. Batteries: 2 x 2032 Coin Cell batteries from whatever brand you like
  4. Cables and Adapters:
    1. USB OTG cable (or some sort of Micro USB to USB C Adapter, not sure what will work as I haven't tried any adapters)
    2. USB A to USB C Cable (not needed if you bought an adapter)
    3. A Micro USB to USB A cable to connect the Gemma to your computer and upload the files
Adafruit Gemma
Adafruit Gemma m0
The main board

This is an inexpensive (about $10 USD) board, that is about the size of a quarter. It also has a micro usb port and JST for solderless power!

Adafruit Coin Cell Batery
Adafruit 2 x 2032 Coin Cell Battery
Solderless Power!

This cheap 2 x coin cell holder has an on/off switch and a JST connection to easily power the Gemma.

Coin Cell Batteries
Coin Cell Batteries
2 x of 2032

These are simply coin cell batteries, they don't need any explaination...

For conneting to USB A/C cable

I purchased a 3 pack of these on Amazon for use with an Android phone. They work here as well.

Adafruit Coin Cell Batery
USB A to C Cable
To connect to the Switch

I had this already for plugging my Switch into an external battery pack. You could also use the cable the pro controller comes with.

Coin Cell Batteries
Micro USB to USB A
To connect to computer

You probably already have one of these...

Putting it together

The parts I chose were for ease of use. Its extrmely easy to put together!

  1. Put batteries in the batter holder
  2. Plug the battery pack into the Gemma, and turn both switches on
  3. ???
  4. Profit
Put the batteries in
Putting the Bateries In

If it doesn't work, you probably put them in upside down...
I did the first time =)

Power it up
Plug it In and Power On

Plug the battery pack into the Gemma, and make sure both the Gemma and Battery have their power switches turned on. The LED will cycle R-G-B colors with the default software on the Gemma.

Software Installation

Follow this github repo's instructions: https://github.com/noemu/sam-fusee-launcher

The instructions are for a Trinket M0, but they are the same thing, except when you select your device from the Arduino software, you will chose Gemma M0.

You obviously don't need to follow the part about putting the hardware together in the github repo, since it doesn't apply to us.

Sending the Payload

Its pretty easy

  1. Power your Gemma on
  2. Put Switch into RCM Mode
  3. Plug your Gemma into your Switch with your cables/adapters

Here's a video of it in action. I was a bit excited that it worked on the first try. I use Auto RCM on my Switch.

Credits / Thanks

I dind't come up with any of this on my own, but was inspired by a few other reddit threads and some comments by others.

Reddit user liocer who mentioned using a Adafruit Gemma M0. I never heard about them, and everyone always talks about the Trinket M0. liocer also linked to the github repo that has the code we use.

Github user Quantumcross who's fork I used for my very first instlattion on the Gemma. Its geared towards an internal trinket, but it works. I ended up using the original repo it was forked from.

Github user atlas44 who created the launcher for an external Trinket M0 dongle. It works for the Gemma as well =)

Everyone who created the tools/payloads from the switch hacking scene