davidlo@madvax.UUCP (David Lo) (07/02/87)
I have a Trackball for an older Atari Computer.
( For which Atari I don't exactly know, it was picked up by my
co-worker at a flea market or something )
It has a DB-15 male as its connector, and three buttons.
Someone here did some hardware hacking to convert a trackball before,
but I no longer remember the content. I think it was posted by Leo.
Since it has been a while for the last posting anyway. I would like
to consult netters here the hardware hacking required to covert the
trackball.
Well... I am no hardware type at all. But hopefully the schematic
is clear enough so that I can handle it.
--
David Lo (415)939-2400 /\ o
Varian Instruments, 2700 Mitchell Drive, Walnut Creek, CA 94598 \/
{ptsfa,lll-crg,zehntel,dual,amd,fortune,ista,rtech,csi,normac}varian!davidloford@crash.CTS.COM (Michael Ditto) (07/03/87)
There is an Atari trackball which is commonly available in toy stores (I just bought one for $8.95). It has a normal optical shaft-encoder type mechanism producing quadrature signals, and a circuit to convert this into direction/ step signals which are output to the connector. A while back, someone posted a circuit that would convert this back into the quadrature signals the Amiga likes, but I just tapped in to the original signals. Here's a basic description: The trackball I have has a brown plastic top half and a beige plastic bottom half, a yellowish que-ball sized ball, and two buttons which are connected to each other (i.e. the same pin on the connector). It has a sticker that says "ATARI TRAK-BALL" just below the ball. It also has a "Joystick -- Trackball" switch on the side. Inside the cabinet, the cable plugs into the circuit board with a 6- pin connector, with a seventh wire going straight to one of the two buttons. The six wires are black, orange, blue, white, brown, and green. I removed the wires from the connector and soldered them to the circuit board as follows: Black: pin 1 of 6-pin connector (same pin it used to be on) Orange: pin 2 of 6-pin connector (same pin it used to be on) Blue: hole labeled "TP2" on printed circuit White: hole labeled "TP3" on printed circuit Brown: hole labeled "TP1" on printed circuit Green: hole labeled "TP4" on printed circuit Leave the red wire connected to the buttons as before. This configuration allows the trackball to be used as a mouse; rolling it away from you moves the mouse pointer upward on the screen, etc. For some reason, Marble Madness does not expect this and you have to use the "mouse" setting. I don't know if there is any difference between the trackball and mouse settings anyway, other than the fact that their trackball setting is "upside down" from the mouse setting. Note that this does not address the problem of having both buttons connected to only one button input. Another wire alongside the main one, or a replacement cable would take care of this. Unfortunately, I don't remember which pin (TP1, etc.) is which quadrature signal or Amiga connector pin number, but you can figure it out with a continuity tester and the original cable, using my connection description above. That's it! It actually is just bypassing the extra level of convertion that was already in the trackball. So dig out the old Marble Madness disk and have fun!! And play around with workbench with a trackball; you might like it better than a mouse, but you won't get far without a menu button. -- Michael "Ford" Ditto -=] Ford [=- P.O. Box 1721 ford@crash.CTS.COM Bonita, CA 92002 ford%oz@prep.mit.ai.edu
peter@sugar.UUCP (Peter DaSilva) (07/06/87)
Ayou don't have to kludge up a menu button (though it would be nice). Alt- Right-Amiga does an acceptable job. -- -- Peter da Silva `-_-' ...!seismo!soma!uhnix1!sugar!peter (I said, NO PHOTOS!)