mwilkins@p3.f55.n282.z1.mmug.edgar.mn.org (Mike Wilkins) (03/04/91)
KB> Could someone also email me the atari trackball mods? Thanks!
Sure! Hear it is...
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Path: van-bc!ubc-cs!ubc-vision!uw-beaver!cornell!rochester!ur-tut!sunybcs!boulder!hao!oddjob!uwvax!speedy!mark
From: mark@speedy.cs.wisc.edu (Mark Spankus)
Newsgroups: comp.sys.amiga
Subject: Re: Trackball conversions (repost)
Summary: Another 2600 Trackball -> Amiga hack
Keywords: wico atari trackball to amiga mouse hacks
Message-ID: <5277@spool.cs.wisc.edu>
Date: 23 Feb 88 05:46:30 GMT
References: <718@esunix.UUCP>
Sender: news@spool.cs.wisc.edu
Lines: 125
Well after seeing the recent postings on trackball hacks, I had to put in
my 2 cents worth. I recently purchased an Atari 2600 trackball from the
local KayBee toy store for $9.00. After some initial probing and testing
I discovered that the outputs from the comparator were the same polarity
as my amiga mouse, so no additional inversions were necessary. (Hey did
you know that they work the same way even if the signals are inverted?)
Anyway some friends wanted to make their own Trak-mice so I wrote up my
experiences. It requires no additional ICs or circuit modifications, works
without problems and leaves the original cable intact in case you ever want
to play missile command on your 2600 again. :-)
Atari2600 Trackball Modifications
==================================
NOTE: These modification void your warranty! Don't attempt this if you're
afraid of soldering irons :-)
Unfortunately the cable supplied with the Atari trackball is missing the
wire which has the right mouse button signal. Therefore it is necessary to
either replace the existing cable with one that has the additional wires
or install a second one devoted to just the amiga. I chose the second
approach. Since I didn't want to hack up another joystick extension cord,
I mounted a female DB-9 on the right rear corner of the case, and can now
just plug the extension cord into the amiga & then into the trackball. This
also allows you to leave the original cable supplied with the trackball in
place so that you can use it for it's original purpose. I later removed it
to limit the amount of wire dangling about. Installing a DB-9 is the
SUGGESTED approach!
Alternately you could use all the existing parts and live without the
right mouse button. This will require you to cut several traces and give
up the original use of the trackball. (You will make it amiga-only)
In this case cut the traces on the top and bottom of the circuit board
leading to the colors white, blue, green, brown on the cable to circuit
board connector. Make the connection listed below but replace the
references to pins 1,2,3,4 with the positions of the colors white,blue,
green, brown on the circuit board connector. You won't need to get any
additional parts or make any additional modifications to the buttons,
but you won't have a right mouse button. :-(
-----------------------------------------------------
Parts List:
Joystick Extension Cord Radio Shack #270-1705 $4.99
Female DB-9 Connector Radio Shack #276-1538 $2.49
-----------------------------------------------------
First you will need to open the trackball. There are four screws in the
corners of the base. There are also two plastic posts which slide together
and are difficult to get apart. Remove the screws and slide a knife or
other flat object between the halves. Gently pry the lid off. The posts
are located in the middle of the trackball near the top and bottom. The
top will come completely off. Next take out the ball and the two metal
bars with the slotted wheels attached and set them aside.
If you choose to, mount a DB-9 connector in the right rear corner of the
trackball. This will allow you to keep the extension cord intact. If you
don't want to do this, you can cut off the male end of the extension cord
and drill a small hole in the back to let the cable pass through.
Now on to the wiring. There are several solder pads located on the top
of the circuit board in the lower left corner. They are labeled TP1 - TP6.
There is another one labeled TP13 to the right of TP6. There is also a
resistor labeled R17 (a 10k). You will need to make connections to most
of these points and to the top of R17 (away from the edge of the board).
Using a low wattage soldering iron, make the connections from the DB-9
to the points on the circuit board as listed below. Use any small
wire (wire wrap wire is fine, but a bit small). If you have decided to
directly connect the joystick cord, you will need to figure out the color/pin
arrangement to make the correct connections.
--------------------------------------
Amiga Mouse Connector (DB 9 Female)
-------------
\ 5 4 3 2 1 / Front
\ 9 8 7 6 / View
---------
1 V pulse ----------> TP3
2 H pulse ----------> TP2
3 VQ pulse ----------> TP4
4 HQ pulse ----------> TP1
5 N/C
6 Button 1 (Left)
7 + 5 Volts ----------> To top end of R17
8 Ground ----------> TP13
9 Button 2 (Right)
[Remember the pin numbers are switched left to right when viewing from the
rear of the connector!]
------------------------------------------------
The buttons as supplied are wired together. You will need to cut the red
wire on the right hand switch at a distance long enough to reach pin 9 on
the DB-9. The other end of the wire will be connected to pin 6. If you are
going to remove the original cable, you will also need to make an additional
ground connection from the black wire to pin 8 on the DB-9 or to TP13 which
ever is easier.
This concludes the wiring. Make sure all your connection are secure and
that there are no shorts. Also make sure that the wires will not interfere
with the movement of the ball or slotted disks.
Put the metal bars and ball back in the trackball. Power up your amiga and
plug the trak-mouse in. If anything strange happens, remove the cable
IMMEDIATELY and verify your wiring. The only really damaging mistake is to
make the wrong connections to either the +5 or ground. If everything is ok,
put the top on & screw it back together. Have fun with your new Trak-Mouse!
[It goes without saying that none of you would ever plug both cables into
two machines at once.... Right? You Betcha!]
Mark Spankus
University of Wisconsin - Madison
Computer Science Systems Lab
path: ...!{allegra,heurikon,ihnp4,seismo,ucbvax,uwm-evax}!uwvax!mark
arpa: mark@speedy.cs.wisc.edu
Mark Spankus
University of Wisconsin - Madison
Computer Science Systems Lab
path: ...!{allegra,heurikon,ihnp4,seismo,ucbvax,uwm-evax}!uwvax!mark
arpa: mark@speedy.cs.wisc.edu
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Mike Wilkins (mwilkins@mmug.edgar.mn.org)
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