[byuu]

You can to varying degrees, yes. There's a barcode scanner, an exercise bike, a baseball bat, and more. I designed higan around a modular tree structure so that you can just create a new derived node for any peripheral, and define whatever API you like, so that we can emulate the protocol. Then it's up to the GUI to figure out how to do something when it sees Node::ExerciseBike, and how to do I/O with its API interface.

One could imagine, for instance, connecting an actual USB barcode reader to emulate the Barcode Battler, or providing a text box to hand-type a barcode number.

I don't see anyone actually bothering to simulate the entire horse betting network complete with virtual bank accounts, but if you're really interested, Raphael Assenat reverse engineered quite a bit of the JRA-PAT system for fun here:

https://www.raphnet.net/divers/retro_challenge_2018_09/index...

It's a pretty good read as well!