The latest incarnation of the Vandervort/Tilton Masterplay clone.
*** 100% 2600 stick comatibility achieved ***
Mark Vandervort (hy648@cleveland.Freenet.Edu) came up with a clever
idea to allow you to connect a regular 2600 stick to a 5200.
I
massaged it a little to come up with what's presented here, but Mark's
original idea was the inspiration. There's still a lot of the
original
in the current design.
If you recall the last revision that I posted, there was a small
incompatibility problem with a couple 2600 sticks. No more!
Adding two diodes makes it 100% compatible! Works great with
every
stick I could drag out of the closet, including the 2600 remote
control joysticks and my Gensis-to-7800 pad. I've been using
it
for some time now with dynamite results.
Build one for yourself and try it out. You'll love it!
If you can't get it to work, send me (Jay Tilton / jtilton@vt.edu)
your
questions.
Materials needed
* (2) 1 megohm potentiometer, Radio Shark #271-211
* (2) 1 kohm resistor, Radio Shark #271-1321 (includes 5)
* (2) PNP 3906 transistor or similiar, Radio Shark #276-1604 (includes
15)
* (2) 1N4001 diode, Radio Shark #276-1101 (includes 2)
* (1) 9-position male D-sub connector, Radio Shark #276-1537
* Some way to connect to the 5200 controller port. Radio Shark
doesn't have any 15-position female D-sub connectors, but it's
come to
my attention (thanks, Ted) that Best Electronics does.
In a real
pinch, you can take 25-pin connectors and cut them down with
a hacksaw
to 15-pins to make a Y-adapter that pipes the keypad/function
key stuff
(pins 1-8) to a regular controller, and the joystick-related
stuff
(pins 9-15) to this thing.
* Tiny wires, and lots of them.
* Beer, preferably something good. Real beer isn't trasparent.
Real
good beer isn't even translucent.
Schematic
5200 port
2600 stick
---------
----------
pin 12 +5V------------------------pin 7 +5V ]Not
entirely necessary
] unless you're using a
] rapid-fire stick/adapter.
pin 15 Ground---------------------pin 8 Ground
pin 13 Bottom Fire----------------pin 6 Fire
pin 10 H-pot----------->|---------pin 4 East ]
| 1N4001
]
|
]
| 1M pot
]Duplicate all this
|-----------\/\/\/--
] for the vertical
|
^
] control circuit.
| Pin 9 Pot_|
] Mentally substitute
| Common
] the following pin
|
] numbers:
|______
] Port pin 10-->11
\ 1 kohm
] Stick pin 3-->1
PNP \|___/\/\/\__pin 3 West ] Stick pin 4-->2
3906 ^|
]
Pin 9 Pot__________/
]
Common
]
Function
* Pushing east on the stick shunts the horizontal circuit to ground,
mimicking the effect of infinite resistance between pot common
and
H-pot.
* Pushing west causes a short circuit between pot common and H-pot,
i.e. zero resistance.
* The potentiometers let you adjust the center position. Additionally,
the potentiometer in the horizontal circuit can be used quite
effectively as a paddle controller for games like Super Breakout.
* The fire button works exactly like it does on the regular 5200 controller.
Good Things
* No more problems with games that were unplayable with your crummy
non-centering 5200 sticks.
* Cheap! Figure buying everything you need from Radio Shark, including
a nice project case to stuff it all into, would cost less than
eight
dollars.
* It should work with every 2600 joystick under the sun. I've tested
it
with my regular mechanical switch sticks, my Genesis-to-7800
pad,
my NES-to-7800 pad, and my 2600 remote control sticks, and they
all
work peachy-keen.
Bad Things
* No second fire button. If you want, you can glue an extra fire
button
onto your 2600-compatible stick of choice. Just wire it up between
port pins 14 and 15.
* Won't work with games that require the analog capabilities of the
5200 stick, like Missile Command. A few other games like
Centipede
and Galaxian make limited use of the analog-osity of the regular
stick by giving two movement speeds depending on how far you
push the
stick. With the adapter, you can only get the fastest
speed. It's
not a huge handicap, but it's probably worth mentioning.
* Neither this adapter nor the Masterplay interface gets along well
with
three particular games: Qix, Vanguard, and Ms. Pac-Man.
There could
be others, but I only own a third of the released 5200 library.
They
will respond to pushing east (or south) on the stick as if you're
pushing west (or north). No real clue exactly why this
happens, but
there is a way to work around it. Start up a game, slowly rotate
the
two potentiometers through their full range a few times while
thrashing the stick around, recenter the potentiometers, then
start
a new game.
Possible enhancements not yet implemented
* 7800 stick compatibility (i.e. with two built-in fire buttons)
* Genesis pad compatibility
* Jaguar controller compatibility (Using the built-in keypad.
Tricky.)
* 2600 paddle compatibility
* Selectable/adjustable rapid fire
I've received a question wondering whether there are any plans to put
this device into a limited-production run for sale to netters.
If
there's a large enough calling for it, I can certainly investigate
the possibility.
If it were to go into any sort of production, it would have to be a
nicely done unit, meaning the tangle of wires would be replaced with
a printed circuit board, the correct plugs and jacks, no-brainer
plug-n-play operation, and a nice case. My personal vision of
the
final product would be functionally *identical* to the coveted
Masterplay, except it wouldn't have the slide switch that lets you
use the joystick fire button as the "start" button. (Pah!
Who needs
that bit of featurism?) A wild-ass-guestimate of the cost would
be
less than $20. Maybe it could be done for even less in kit form.
If you're interested in this, drop me a line. I ain't promising
it
will happen any time soon, or that it will happen at all. I'm
just
looking to guage initial interest in such a thing before I invest my
time in scoping it out.
Skoal!
--
Jay Tilton | jtilton@vt.edu | Virginia Tech
http://fbox.vt.edu:10021/J/jtilton/index.html