This program requires the ComputerCraft mod for Minecraft.
These programs work to together to make an LED connected to the Raspberry Pi when a lever is switched in Minecraft. The LED can connect to any free GPIO pin on the Pi. It is connected to pin 23 in my example
The python file runs on the Raspberry Pi. You will have to run it as root: sudo python LED.py
The other file goes on the computer in Minecraft. You can either move it into the proper directory in your Minecraft saves folder. The command line parameters for the startup program are: startup [raspberry pi url] [side] [delay]. The raspberry pi url has to have http:// at the beginning and the port :3141 at the end. Delay is how long to wait between polls. It is recommended to have at least a one second delay. The default values are http://raspberrypi.local:3141, top and 1.
This program is not just limited to LEDs and levers. It could be expanded to control nearly anything connected to the Pi using a variety of items in Minecraft.