The Nintendo 64 is my favourite games console and I have many fond memories of playing it when I was much younger. In the past few years I’ve acquired an N64 with a PixelFX Retro GEM HDMI mod and have been playing using an official Nintendo controller modded with the 8bitdo mod kit (keeping the original stick) and a blueretro adapter.
One frustration I have with the 8bitdo mod kit is that it’s difficult if not impossible to make it work nicely with a PC running an emulator or a PC port of an N64 game. The controller is somewhat unique and so using anything else feels odd. I wanted to find a solution to use the controller on my PC.
I looked at a few existing options, but they all had drawbacks:
- The mod kit only supports rumble in “S” (Switch) mode, but only works nicely without random drivers in “D” (D-input) mode. This is pretty annoying.
- 8bitdo do sell a USB adapter which can connect to the mod kit (in “S” mode) and present it as an X-input device via USB, which then supports rumble effects. However, there seems to be extreme latency on the rumble effects which detract somewhat from the experience.
- The blueretro implementation works really well. It uses an ESP32 for bluetooth and talking to the N64. I believe it uses the two cores in the ESP32 to separate the bluetooth and USB communications which help provide great latency. Blueretro would have been a preferred starting point, however it’s written and optimised for the ESP32 for which most development boards don’t contain a USB port that can be used as a USB device.
The Raspberry Pi Pico W can act as a USB device and also has bluetooth built-in. I decided to see if I could make this do what I want.
There are two similar projects that I looked at before embarking on creating something new: PicoGamepadConverter and OGX-Mini. I couldn’t get either to work properly for me though I didn’t spend too long trying.
I ended up starting a new project and experimenting with gemini-cli to write it, having only a small amount of experience with programming bluetooth and less for USB. I found gemini-cli very slow to respond, but over the course of a few nights managed to get something that worked. I’ve pushed it to github as davids_pico_gamepad.
Currently I can only confirm it works for my niche use case but I’d like to expand it to work with more bluetooth gamepads. I’ve developed it on a Raspberry Pi Pico 2 W but have ordered a Pico (1) W to test with. If you have a Pico W/Pico 2 W and a USB gamepad lying around please give it a go and let me know what works!