I have in plan to build a joystick/gamepad with an Pro micro and a multiplexer for more inputs.
I want to play games like Farming Simulator or Euro truck simulator. I have around an old wheel setup and not functional.
Idea is to use as much as possible potentiometer and buttons for actions like, throtle, brake, steering.
I have seen many post but nothing that can complete my idea. I know that it must be used a HID but i dont know how.
It sounds to me that some more research is needed for you to at least define your project.
"More learning is always better."
This is easy i know, i just haven't figure out how to make it to works.
Projects that use a micro as a joystick are very common - people make custom controllers and hack existing controllers to act like standard HID joysticks all the time.
I'm not sure why you haven't been able to find more information on this - it's all over the web. More research would serve you well; I'm sure there are some project writeups for something close enough to what you're doing that it would be straightforward to adapt.
You're right the web is full of controller but no one have made one with more analog pins that arduino support. A multiplexer i ideal for this but i dont know how?
Really? You need more than TWELVE analog inputs?!
The Leo has 12 analog inputs - a bunch of the so called "digital pins" have ADC capability (the distinction between analog and digital pins is IMO misleading; all the "analog pins" are also fully functional "digital pins" (except A6 and A7 on the '328p smd version, which are analog only) - they just have the added ability to read analog voltage, like some pins can output PWM)
From leo documentation:
Analog Inputs: A0-A5, A6 - A11 (on digital pins 4, 6, 8, 9, 10, and 12). The Leonardo has 12 analog inputs, labeled A0 through A11, all of which can also be used as digital i/o. Pins A0-A5 appear in the same locations as on the Uno; inputs A6-A11 are on digital i/o pins 4, 6, 8, 9, 10, and 12 respectively.
Yes i need more than 12 pins. Steering throtle brake gears and much more buttons.
Arduino mega is not an option for me right now.
Mega wouldn't work anyway, it doesn't have native USB so it can't pretend to be a HID device...
So what are you doing for the buttons? Are you making them like, pressure sensitive, so pressing hard vs lightly will do different things? Can you do that for buttons with USB HID? How will it be treated by applications that expect buttons to be on or off?
Is there a limit to how many analog values USB HID will support? You should do some research on these matters before proceeding.