The SD Card image will auto-start the Fuse emulator and joystick program. The SD Card uses a read-only file system, but with a read-write folder at /rw. This will allow you to save any programs you create on the SD Card.
If you wish to modify the SD Card contents in any way, then exit the Fuse emulator and type ipe-rw at the command prompt, this will convert the file system to read-write, ipe-ro will set the file system back to read-only.
The Joystick program can be found /home/zx/joystick and is called joystick.py. The program emulates key presses as the joystick is moved. The key presses are Up – 7, Down – 6, Left – 5, Right -8 and Button – 0. This can then be used within any program you create just by reading these keys!
The hardware for the joystick interface can be built from an up-cycled old PC serial port. Most old PC computers had a 9 pin D type socket with a small header on the end. The header will need to be cut down so that it fits between the pins on the GPIO of the Raspberry Pi, and a couple of wires need to be de-soldered and moved on the D socket.
Figure showing D Socket pin numbers to GPIO
Download the SD card image and Instructions