Digital 5200 Controls: Instructions 2.

[Aswald]

PART 3: BASIC WIRING.

Hmmmm...now we get down to it!

The 5200 controller wiring is complicated only if you try to take it all in at once, looking in an actual 5200 controller. In reality, the scheme is pretty basic: with the exception of the joystick controls, everything else is simply a matter of 2 different wires touching to achieve something. That's it.


So, without further ado...here it is!


VERTICAL= RED and BLACK (with potentiometer).
HORIZONTAL= BROWN and BLACK (with potentiometer).

UPPER FIRE BUTTON= GREEN/WHITE and ORANGE.
LOWER FIRE BUTTON= YELLOW and ORANGE.

START= RED/WHITE and ORANGE/WHITE.
PAUSE= PURPLE and ORANGE/WHITE.
RESET= BLUE and ORANGE/WHITE.


Keypad Buttons:

1= ORANGE
2= WHITE (1, 2, and 3 touch RED/WHITE)
3= GREY

4= ORANGE
5= WHITE (4, 5, and 6 touch PURPLE)
6= GREY

7= ORANGE
8= WHITE (7, 8, and 9 touch BLUE)
9= GREY

*= ORANGE
0= WHITE (*, 0, and # touch GREEN)
#= GREY


In other words, touch ORANGE and GREEN and you "press" *. Touch GREY and GREEN and you "press" #. Touch WHITE and PURPLE and you "press"...if you said 5, then you have it.


Now, these colors assume you are actually using the cable from a 5200 controller. What if you don't have such? No problem, because here's where those wires lead to in a 5200 cable:

The 5200 controller plug has 15 holes: there are 2 rows; 8 in the top row, and 7 in the bottom row.

OOOOOOOO
OOOOOOO

I will number them. This assumes you are looking at the holes in the plug, with the 8-hole row on top:

01 02 03 04 05 06 07 08
09 10 11 12 13 14 15

01= GREEN
02= RED/WHITE
03= PURPLE
04= BLUE
05= ORANGE/WHITE
06= NOTHING
07= WHITE
08= GREY
09= ORANGE
10= GREEN/WHITE
11= YELLOW
12= NOTHING
13= RED
14= BROWN
15= BLACK

I also found a BLACK/WHITE wire, but it does not appear to do anything. It does not lead to any of the holes.

So- what if you have a 15-pin controller cable from something else? All you have to do is use a multi-tester to figure out which wire leads to which hole (if the multi-tester prong is too big to fit in the holes, just twist a bit of stiff wire to the prong).

If, for example, in your cable the GOLD wire leads to Hole 7, then treat it as the WHITE wire listed above. If the SILVER wire leads to Hole 12, then it is of no use; seal it off.

[Aswald]

PART 4: THE JOYSTICK ITSELF.


This part is in conjunction with the diagrams...

As mentioned earlier, the 5200 joystick control is analog, not digital. In this case, the joystick actually turns two little variable resistors ("potentiometers"); one controls the vertical, the other, the horizontal. It is exactly like two tiny paddle controllers (a paddle controller IS a potentiometer).

As you already know, when you play Pong, Breakout, Super Breakout, Arkanoid, Canyon Bomber, or any game with a paddle controller, there is a point when the paddle (or whatever) is centered. This is because the resistance is at the point when the video game puts the object in the middle. This is important: when you release a normal joystick, it is "centered" because the game is not receiving any input from it. In the case of a 5200 joystick, the stick is "centered" only because the values of the two potentiometers are such that the game knows not to do anything (e.g. "don't move the Humanoid in Berzerk").

Vertical: Low Resistance=UP; High Resistance=DOWN.

Horizontal: Low Resistance=LEFT; High Resistance=Right.

When you unplug the controller, you are completely breaking the circuit. Electricity cannot flow. This is the same thing as VERY VERY VERY high resistance; that's why the game acts as if you have jammed the joystick down and to the right.

If there wasn't ANY resistance to these 2 currents, it would be as if you jammed the joystick up and left.

Therefore, the "neutral" position is between the two extremes.

Unfortunately, I cannot give you these values. My testing equipment is not precise enough to do it; this is why I hooked up the 2 potentiometers to my joystick set-up; I simply adjust them until they are both at the neutral value. These two potentiometers take the place of two "fixed" resistors. Just keep in mind that, once adjusted, THESE TWO POTENTIOMETERS ACT AS TWO FIXED RESISTORS THAT WOULD HAVE THE "NEUTRAL" VALUES!

Therefore, as long as you do nothing, the 5200 is receiving the same two values you would get if you properly centered a 5200 controller. Nothing happens.

What my controller does here is to alter that "neutral" value. Lessen if you want to up/left. Increase if you want to go down/right.

At this point, I should explain two things about connecting resistors: "Series" and "Parallel."

"Series" connection is when you connect two (or more) resistors end-to-end, much as you would do two batteries in a flashlight (resistors, luckily, do not have a polarity). When you do it this way, you simply add the resistances to get the total. So, connecting two 10 Ohm resistors end-to-end gives you a total resistance of 20 Ohms. Pretty much what you'd expect.

"Parallel" connection is when you put two resistors right next to each other and, say, twist them together, as if you were twisting two garbage ties together to get one double-strength garbage tie. If you do this with two resistors, to find the resistance you end up with use this formula:

(Resistor 1)X(Resistor 2)
_____________________

(Resistor 1)+(Resistor 2)

Helpful Hint: if they are of the same value, you simply cut the value in half. Two 10-Ohm resistors would become a 5 Ohm resistor.

So- let's take those two 10-Ohm resistors and twist them together. What do you get?

(10X10)/(10+10)= (100)/(20)=5!


This is the heart of my 5200 Digital Joystick. When you pull down and/or to the right, you are ADDING (in my case) 235,000 Ohms to the Neutral value(s). It is a series connection. When you push up or to the left, you are creating a parallel connection (you obviously can do this without twisting the two resistors together!), which greatly LOWERS the resistance(s). Since I use 10-Ohm resistors for this, and the neutral value is very high (thousands), you end up with a value a bit less than 10 (try the formula and see what you get).

There are 2 diagrams here. One shows the 2 separate circuits; the other, combined.

[Aswald]

This is where it gets tricky. I cannot scan and upload those diagrams. I must send them to somebody here- by regular mail- who can.

[Aswald]

PART 5: PROBLEMS?

Keep in mind that this joystick is the first one I actually built. 99% of the time, it works great; my scores immediately improved, and it just feels more like the arcade versions did.

However, there are a few minor problems.

First of all, Super Breakout and Missile Command cannot be played with this controller.

Secondly, in the initial design, I simply cut the current altogether (rather than adding 235,000 Ohms) when pulling down or to the right. This worked, until I tried a few games.

Qix and Ms. Pac-Man would not work at all. Without trying any others, I knew that the design had to be changed. I noticed that Qix did work, until you tried to go down or right- therefore, cutting the current was wrong.

The Down and Right switches used are "Normally Closed" switches. These are push-buttons that let current flow until you push the button (the opposite of a "regular" push-button, like the sort used for a door bell).

Now, to understand how this works, remember that electricity is lazy. It will always try to find the path of least resistance. I simply soldered a 235,000 Ohm resistor across the two contact points on those two switches. Since, when they are not being pushed there is NO resistance, that is where the electricity will flow- but, when you do push them, that circuit is broken, leaving the electricity no choice but to cross the 235,000 Ohm resistors- thus, adding that to the overall circuit (you down and/or to the right!).

Once these were added, almost all of the problems disappeared. However, in certain games, you must:

Defender: Each time you begin a new game, you must pull down for a split second.

Ms. Pac-Man: Same as Defender.

Qix: Same as above. Problem often does not occur in any case.

Kangaroo: Quickly move joystick in all four directions at beginning of new game.

Star Raiders: Same as Defender.


Note that once you do this- and it only takes a split second- you are fine for the rest of the game; in a couple, as long as the cartridge is plugged in and the 5200 is on.

My guess is that 235,000 Ohms is still a bit off, judging by previous efforts. 250,000 Ohms may be the "ideal," but I will attempt that with the next joystick I build; these problems are so split second and so minor, I'm not going to bother with this one.