Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!ucselx!crash!jcs
From: jcs@crash.cts.com (John Schultz)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: A "legal" way to access a potentiometer ?
Summary: Here's how to adapt IBM analog joysticks (range 0..255)
Message-ID: <7680@crash.cts.com>
Date: 21 Feb 91 18:59:28 GMT
References: <1258@theseas.ntua.gr> <28702.27c2619a@kuhub.cc.ukans.edu>
Distribution: comp
Organization: Crash TimeSharing, El Cajon, CA
Lines: 53

In <28702.27c2619a@kuhub.cc.ukans.edu> markv@kuhub.cc.ukans.edu writes:


>I've also had some severe problems with jitter, so I use a running
>average of the last 3 values.  The optimum pot value is supposed to be
>470K, which works okay on the 1000 and most 500 and 2000s, but the
>3000 seems to want even more (I dont get a full 255 value on our 3000
>w/470K ohms).

  If you want to get the full 0..255 range, you'll need about 1Meg Ohm
pots, or a couple of .22uf caps. Here's how to adapt IBM analog joysticks
and get full range. I recommend the CH Products Flight Stick. Best analog
joystick I've seen.

                   IBM->Amiga Analog Joystick Adaptor
                            with pass-through
                                   by
                              John Schultz
                            October 25, 1990

Parts:

  1 IBM analog joystick (I recommend the CH Products Flight Stick)
  1 DB-9 female
  1 DB-9 male
  1 DB-15 female
  2 .22 microfarad tantalum capacitors
  16 3-4 inch strips of appropriate gauge wire

Pinout:

            Amiga                     IBM
         DB-9 female              DB-15 female
         -----------              ------------

button 3:     1                       10
button 1:     3                        2
button 2:     4                        7
pot X   :     5                        6 (Future will be 3)
+5 Volts:     7                        1
ground  :     8                        4
pot Y   :     9                        3 (Future will be 6)

Construction:

  Wire the DB-9 female to the DB-9 male straight across. Wire the DB-15
female to the DB-9 female. On the DB-9 female, add the capacitors between
pins 5 and 8 and between pins 9 and 8 (+ on 5 and 9, - on 8).

  The code and adaptor were made originally to work with SubLogic's Jet,
but the documentation for IBM joysticks shows pins 3 and 6 reversed from
what worked properly with Jet. Future versions should reverse those pins
for compatibility with the documentation.