How can I emulate a joystick using a python script?

A Former User

I have a custom-built joystick sending data to a python script, how can that python script emulate a controller so that it would be usable in emulationstation/retroarch? (Connecting the joystick directly to emulationstation/retroarch won't work due to the way I built it)

mitu

Yes, it's possible - something like https://github.com/mholgatem/GPIOnext should work.

A Former User

@mitu Sorry, the input is not GPIO, I need it in a Python script, with variables such as X and Y being the position of the joystick (to make it clearer could you add "(from variables in Python)" to the title as I can't for some reason...)

luizoti

With python-evdev I believe it is possible to do whatever you want.

A Former User

@luizoti How exactly would I emulate a joystick? It seems to need a joystick already plugged in...

luizoti

@Bluebotlabs How exactly does this control work? I probably didn't understand.

A Former User

@luizoti Ok, so I'm building a nintendo switch, I have two arduino's, one is connected to main one via RF which is connected to the Pi via bluetooth, they both have nintendo switch joysticks in them and will be able to send whatever data they have to to the pi, I need to figure out how I can configure ES to use the controllers, e.g: via a Python script interacting with the controlers and emulating a joystick

luizoti

Well, if I understand your control connects, but it is not seen as a control, I have already programmed a usb control with arduino, and ES recognized it normally, I believe that via BT it is possible, I did not need any python script.

The library I used at the time, I remember allowing programming joystick axes.

About py-udev, remember that it reads the events of the device and you can create a new device based on it, joystick becomes a control for example.

A Former User

@luizoti I do not beleive you can emulate a joystick over bluetooth

Does anybody know how to use python-uinput?

mitu

@Bluebotlabs said in How can I emulate a joystick using a python script?:

@luizoti I do not beleive you can emulate a joystick over bluetooth

Of course you can, there's lots of projects using an inexpensive BLE HID chip to add wireless connectivity to classic controllers (SNES/Megadrive/etc.).

EDIT: here is one - https://mitxela.com/projects/bluetooth_hid_gamepad.

luizoti

@Bluebotlabs Exactly as mitu said, it is possible, python-uinput would be useless (probably) if your control is not recognized as a control or at least a keyboard, the BLE HID project, seems something much easier to apply.

A Former User

@luizoti However, the BLE HID project is out of the question for me due to reasons regarding budget, availability, size and others. I have tested python-uinput and pygame appears to detect it, ~~I shall do some further experimentation and update you on the result~~

python-uinput did not work, I'm going to try using evdev, does anybody know how I can emulate a joystick using it?

mitu

@Bluebotlabs said in How can I emulate a joystick using a python script?:

python-uinput did not work, I'm going to try using evdev, does anybody know how I can emulate a joystick using it?

It's actually python-uinput that should be used to create an input device, the evdev part it's used to read from the existing event sources (emph. mine):

The evdev interface serves the purpose of passing events generated in the kernel directly to userspace through character devices that are typically located in /dev/input/.

This package also comes with bindings to uinput, the userspace input subsystem. Uinput allows userspace programs to create and handle input devices that can inject events directly into the input subsystem.

A Former User

@mitu I made a mistake in my testing, I beleive python-uinput my work