Test the functionality of your vintage C64/Amiga style joystick
Use the Joystick Tester to test if your vintage joystick works without plugging it into your vintage computer. Will tell you whether all four directions (up, down, left right) as well as the fire button works, and it comes with a switch to optionally feed the joystick with 5V. Power the tester with a normal mini-USB lead, or connect your own battery or similar to the provided solder pads.
I originally developed this Joystick Tester in order to quickly and easily test the various development revisions of my NES64 board, but I thought other people might find it useful as well.
The Joystick Tester has been released as Open Source hardware, so if you feel for it, you can get the source files and do your own changes, or get the gerber files and have the board printed yourself at your favourite PCB manufacturer. This link is also where you will find the assembly instructions.