If you would like to know a little more about the Atari Punk Console before you start check out this video from Collin Cunningham, http://www.youtube.com/watch?v=Oi3dmSMpjsU
This article from Jameco also has some useful info. http://www.jameco.com/Jameco/PressRoom/punk.html
Step 1: Get a Joystick
Finding and Selecting a Joystick:
Finding a joystick has been fairly easy in my experience. Literally every time I have gone to Goodwill or Salvation Army there have been at least five. They are usually around three dollars. Keep in mind the simpler the joystick the easier it is to convert. Some more complicated joysticks, such as the one on the right in the first picture, actually use an optical system and not potentiometers to track their position. This might be great for a project with Arduino integration but for the purposes of this project its far too complicated. The square shape of the one in the middle made it very easy to mount everything, but it did have a few unnecessary buttons. For this Instructable I will be using the one on the left. It only had one button that did not get used and although the curved shape made it a little hard to mount everything it looks much more sleek.
Testing the Joystick:
Once you have a joystick selected you will want to open it up and marvel at its simplicity. Once you have finished doing that, you will want to hook up a multimeter up to each of the two potentiometer that the control column (the stick part) is attached to. There will be a third potentiometer not attached to the stick that will be taken out after, as it is not needed. You will want to hook up one lead of the multimeter to the center leg of the potentiometer and one to either of the side ones (polarity doesn't mater here nor does which of the side legs). So far every joystick I have dissected has used a 130K ohm potentiometer for both axises but it is worth testing just to make sure. Once you have determined the value you are going to want to remember it because you will use it to determine the value of a second set of potentiometers you will add.
Determining Which Wires are Which:
Part of this build involves using the original trigger or "fire" switch as a sort of kill switch for the punk console. Since there are two switches on the joystick and we only need one we will want to determine which two of the three wires going into the stick itself we will need to utilize the trigger (my stick only had 3 wires although if your stick has more buttons it will probably have more wires.)
As long as you have your multimeter out you may as well set it up to do a continuity test and do this now. Hook one lead of the continuity tester up to the black wire and the other lead up to any of the remaining wires and pressing the button you wish to use, if the multimeter beeps, or lights up, or does whatever yours does, you have found the combination of wires you will use for the switch. If it doesn't, keep hooking it up to different wires till it does.
Step 2: Parts and Tools
An old, simple joystick
A switch (the cooler looking the better just as long as its SPST.)
A 9v batter clip
A mono audio jack (I went with 1/8" but you could go with 1/4" if you want to hook it up to a guitar amp.)
Some hook-up wire (different colors help keep track of things but are not totally necessary, although you should use stranded and not solid as it is much easier to make fit in small places.)
2 Potentiometers (to determine what type you need, you take the value of the potentiometers in your joystick and subtract that number from 470k. You don't have to be very exact with this; I have up to 1m ohm potentiometers and they work just fine if you cannot get it exact, though you will want to go with more resistance as opposed to less)
100 nf (.1uf) ceramic (I didn't have one so I used two .047uf caps; it was close enough)
10 nf (.01uf) ceramic
A 556 timer
A proto board (any kind will do as long as it fits in your joystick)
A 9 volt battery
A soldering iron
Measuring tools (a ruler will work fine)
A rotary tool such as a Dremel
Step 3: Building the Circuit
Step 4: Preparing the Joystick
First I cut off the serial cable that would have hooked up to a computer. I then removed the potentiometer that does not get used. Then I used a rotary tool to take out some of the plastic supports inside of the joystick to make room for the potentiometers, switch, board, and battery.
Drill Some Holes:
You will want to measure your switch, jack, and potentiometers to determine what size holes they will need. If you got them from Radio Shack it will probably say on the back side of the package what size holes you will need. Then you want to determine where you have space on the inside and translate that to the outside and mark where they will go. There is no wrong way to do this just so long as everything fits.
Once you have the holes drilled you can go ahead and start mounting things.