I own a C64 with Quickshot II Turbo joysticks. Unfortunately the joysticks are worn out. On one, one spring of the micro switch is broken and the micro switches are discrete, which means there is a spring between two poles. Without the exactly matching spring it’s not possible to repair. Also the rubber ring which shall bring the joystick back to middle position has dried out over the years. So, buy another pair of used joysticks which are decades old, or find another solution?
The idea: Use two Competition Pro joysticks which are available still today as vintage rebuild but with USB. Important to know: There are two variants available. One which as a slower USB polling rate and one with a high polling rate (125 Hz). In some forums you can read about complaints that the slow polling rate is too slow. So, make sure to get the one with the high polling rate.
Option 1: Connect the micro switches in the joystick and mount a C64 compatible connector. See http://www.stefan-uhlmann.de/cbm/CPUSB/CPUSB.html
Option 2: Convert the USB port into C64 control port digital signals by using an Arduino —> This is described here.
How does it work
The HW is an Arduino Uno and an USB Host Shield ( http://shop.tkjelectronics.dk/product_info.php?products_id=43 ). Furthermore, a breadboard PCB with the switching transistors and the connections of the C64 control port.”