I've purchased a Funduino Joystick Shield, attached it to my Arduino, and uploaded code that allows me to watch joystick presses in a serial monitor on my latop. I then connected the arduino/joystick shield to a raspberry pi 3 running recalbox via usb thinking recalbox would pickup the movements right away but it did not. I tried to configure the joystick manually in recalbox but recalbox does not even recognize its plugged in. Am I doing something wrong? Should I not be using USB from the arduino uno to the rpi3? Thought it would work since the serial monitor on my laptop saw the inputs via usb. Appreciate any help. Thanks!
The Serial monitor on your PC is a Serial as-in a COM port. The driver on your PC recoginizes the USB port on the arduino and makes it a COM port.
Not sure what recalbox is on a rPi, but I'm guessing it doesn't want a serial port, but a native USB device (something like a keyboard or mouse)