How do I make code interact with hardware?

You may have to write drivers for your input devices. And choose/develop the connections you would use to input/export data. If you want a custom output device [an LED instead of a computer-simulated LED] you may need drivers for that too. Will these devices also need power? Ambitious project. Sounds interesting

This would be a great question to ask someone who develops tecchie exhibits for Smithsonian, like one I wanted to do years ago that would have interfaced various submarine parts with multi-user computer control system for an interactive conning tower exhibit [it was too expensive]—same principle as pilot training devices—or on a simpler scale, pedometers that can have contents uploaded to websites so you can track your steps.

To clarify I was thinking of somehow using a Lego Mindstorm set or something similar like those what are used for controlling robots and whatnot but I really don’t know enough to say for sure. And the “hardware” isn’t exactly complicated; just something to input speed and turn on some LED’s.

I would ask over at the Make Forums. This is the type of stuff they do.

http://forums.makezine.com/

You won’t be able to use Python on microcontroller for a while but I’d recommend the Arduino platform. It’s the largest community-wise and pretty darn easy to build awesome projects.

If you must use Python you’ll probably have to buy a PC/104 computer (because Python requires a full-blown operating system. PC/104 systems are a pain in the ass if you don’t know what you’re doing and expensive.