5200 Digital Controller: Completed.

[Aswald]

Over the weekend, having bad weather and therefore not much else to do up here, I decided to work on the 5200 digital controller. Much to my surprise, I was actually able to finish it- guess I was further along than I thought.

I had to alter a few of the original plans, like changing the 6-wire cable for an 8-wire, along with a few other things, but, finally...it was done.

So, plug it in to the 5200. Switch ON the 5200- nothing caught fire or exploded; good, we're doing o.k. so far...

Plug in Missile Command.

* Originally, I had planned on finding the "neutral" value and wiring that in with fixed resistors. Unfortunately, my ancient and beat-up multi-tester can in no way pinpoint that value, and I have neither the time nor the resources to find out by trial-and-error. So, both the vertical and horizontal circuits use the two potentiometers from the 5200 controller (regular analog) instead. Missile Command is perfect for adjusting these two potentiometers to the "neutral" positions.

O.K., you are as close to perfectly aligned when the cursor is right on the lower left corner of the "O" in "POINTS" when the game begins. I did this. Move joystick to left, right, up, down, let it go- good, so far!

Obviously, 5200 Missile Command cannot be played with a digital joystick. So, the first game I actually tried was...

BERZERK!

How many times haven't 5200 owners cursed to controls when they had to make a short maneuver, only to blunder into a wall while the fiendish voice gloats "GOT THE HUMANOID, GOT THE INTRUDER/CHICKEN!"

To my amazement, not now!

One thing that gets me 80% of the time is when you start from the left, and robots are right above and/or below you. Normally, you'd go just a bit to the left, where you can shoot them, but they can't shoot you. BUT, with the 5200 stick...see above. But this time, I actually did it! Not through luck!

Beat 11,000 points- not my best, but it was a test, and I wasn't killed by things that usually did.

Then, Star Raiders. This took some getting used to, but again, it worked.

Mario Bros. Centipede. Pac-Man. Robotron: 2084. Defender. So far, so good.

Qix. Oh, oh- *$%@!*&%$#@*! Not so good. The control did NOT work.

Likewise Ms. Pac-Man, although Pac-Man did.

[Pantechnicon]

Pictures, please.

[Aswald]

So, so far, two games do not work. Ms. Pac-Man I have for the 7800, and will soon have for the CV.

(Note- Soon, Opcode's fantastic Pac-Man Collection will be available for the CV. Do purchase it. Otherwise...you won't have it.)

But Qix- that was one of the main reasons I purchased and repaired the 5200!

After a few tests, I noticed that the game worked fine if you only went up and left. It was when you tried to go right or down the problems started; the same seemed true for Ms. Pac-Man.

You may remember that I installed a switch in the right and down parts of the joystick circuit board that simply cut the current when you moved in these directions. It would be like unplugging the controller. Clearly, this was too much, and fouled up certain games.

Therefore, it was time to try adding a fixed resistor across the switch's contacts. Electricity always chooses the easiest path; it will not move across this while the switch is closed and there is no resistance that way. At first, I tried a 470,000 OHM resistor, but while the problem was not quite as bad, it was still there.

So, try a 100,000 OHM resistor.

No good. Not enough- games like Star Raiders and Centipede were just too uneven. You would move quickly to the left,, but slowly to the right.

My choices were limited.

So, I knew it was somewhere in between. I took 2 470,000 OHM resistors, twisted them together (this makes a 235,000 OHM resistor) and tried that.

Nearly perfect. With games like Ms. Pac-Man and Qix, you must, each time you fire up the cartridge and start the FIRST game, jiggle the joystick for a second or less. From that point on, as long as you play that cartridge, the stick functions perfectly.


So- that's that for that. Maybe there is a more "perfect" resistance (250,000 OHM?), but there's no point for me. It works fine. Centipede, Berzerk, Star Raiders, Robotron: 2084, Pac-Man and Ms. Pac-Man...all play like new games.

NIFTY!!

[Aswald]

There was also something else here.

For many years, there have been endless compaints about the 5200 controllers. We always wondered about having "good" controllers.

Now I have one. Sure, it's built from scraps, second-hand parts, bits and pieces of roofing tin, electrical tape, Velcro (really!), and a few items from a busted 1970s VCR, but it does work so far. And the difference is astonishing. It's hard to imagine.

I just can't help but wonder what the hell Atari was thinking back then. Why, why did they design a controller that could do nothing but make their most popular games nearly impossible to properly play? Didn't they see that it was easier and better to simply use a standard digital controller, like every single arcade game with a joystick used?

Does anyone know? Maybe from some interview or article? The 5200 would have done better if not for those stupid controllers.

[Aswald]

Pictures? Well, here's a start:


This is the joystick I modified and used: an Atari 2600 Gemstik Controller. It uses a 6-wire cable; I had to replace it with an 8-wire. The only visible difference is a small red momentary push button (Radio Shack) just to the right of the big yellow button. The yellow button serves as a "lower" 5200 button; the added red button is for the "upper" button.

http://cgi.ebay.com/Gemstik-Joystick-Controller-Atari_W0QQitemZ250090484699QQcmdZViewItem#ebayphot ohosting


This is the keypad. Note that the white Star Raiders surface is just an overlay; the actual keypad is unmarked black.

http://www.atariage.com/2600/controllers/con_AtariTouchPad.jpg



The cable going to the 5200 comes from the back and center of the keypad.

The joystick cable runs into the keypad at the back and right side. It is therefore more comfortable to keep the keypad to the left of you (as I am right handed, this works).

Right above the normal keypad buttons are three additional buttons: they are identical to what I used for the joystick, but the left and right are black (START and RESET), while the middle one is red (PAUSE).

Above these are the two potentiometers. They are held onto the keypad by Velcro squares. This is the only crude-looking part of this project. the left controls the vertical; the right, horizontal.

[Aswald]

Due to the numerous bits and pieces I used for this, it will be next to impossible to publish any plans that will be of any use to anyone here, based on what I actually did.


However, I CAN publish plans that explain the BASIC workings of this project. While trying to build this, I mapped out the circuits of the 5200 keypad controller. I figured out what wire does what, and where it goes in a 5200 controller. I figured out which wire combinations do what. And, of course, a working circuit plan for a 5200 digital joystick.

In other words, while you cannot duplicate what I did (why would you want to? Velcro? parts from an ancient VCR?), you will be able to build your own based on your own design. It isn't even hard to build your own keypad; once you know which wires do what, it's quite easy.

[Aswald]

And did I forget to mention the thumbtacks used to make sure the contacts don't slip...?

[BydoEmpire]

Awesome, congrats. Sounds like a pretty cool project, and some games will definitely be more playable.

[Aswald]

Oh, yes- especially Berzerk, Ms. Pac-Man, and Qix.

In the coming days I'll publish the plans (as best I can) here, in steps. That way, other 5200 owners can build their own versions. Probably improve on it some.