This instructable will show you how to convert an analog (PS2 type) joystick and adapt it for use as a digital joystick without a PIC or any complex electronics.
Step 1: Materials Needed:
-Analog joystick – I got mine from an old PS2 controller, or you can buy them.
-Sharp hobby knife
-(4) 150K resistors
Step 2: Background:
Analog joysticks control 2 potentiometers, typically ~10K, one for each plane of movement. The output voltage in each plane will therefore vary with the exact position of the stick. We want to change this so that each of the 4 positions (UP, DOWN, RIGHT, LEFT) will just give a logical HIGH. This can be accomplished with the use of a PIC and corresponding code, but all you’ll need for this instructable is a knife!
Step 3: Dismanteling the Joystick
Dismantle the joystick by pulling off the cap, and carefully removing the 2 pots by carefully depressing the tabs along their sides.
Step 4: Observing POT Structure
Pop out the wiper for each pot. Do this by carefully bringing the 2 little plastic tabs on the front together. Flip the pots over and observe the black conducting material and the brown insulation.
Step 5: Remove Conducting Material
Scrape away the conducting material in the Noon position; from about 11:58 to 12:02 as shown.
Step 6: Replace Wiper
Replace the wiper; make sure the wiper is pointing to the Noon position.
Step 7: Replace POTS
Reassemble the pots onto the joystick body; hot glue if broke tabs on side of pots.
Step 8: Wire It Up!
Wiring it up. Note difference from typical analog use; instead of voltage applied across the outer pins, it is applied to the center pin.