Re: Schematic for IIc mouse?

[Michael Black <et472@ncf.ca>]

On Sun, 5 Apr 2009, zwsdotcom@gmail.com wrote:

> On Apr 4, 10:53 pm, Mike Spurgeon <m...@spurgeon.net> wrote:
>
> > > Right, like I said - it's not ADB, it's the 9-pin.
> >
> > I can send you an ADB mouse.  Just email me an address...
>
> Thanks, but I have plenty... I think we're talking at cross-purposes
> here. I want to see if it's possible to modify the Macintosh M0100
> [DE-9] mouse to work with the IIc [also DE-9]. No ADB in sight
> anywhere in this equation.
YOu can't get much simpler than the original Macintosh mouse.  The
mechanical wheels, the optocouplers, the 339 comparators to sharpen
up the signals, and the pushbuttons.

I once traced out the Mac mouse, and when I saw how simple it was,
took a non-Mac mouse, brought out the outputs of the optocouplers and
pushbuttons, I can't remember if I put in pull-up resistors, and plugged
that into my Mac Plus.  I couldn't tell the difference, it seemed to
work as well as the Mac mouse with the built in comparators.

I'm not sure what might might be varied to supply the variance someone
mentioned that allows some mice to work with the IIC and some to not.
The Mac mouse is very simple, and I can't see why the IIC would require
anything beyond that.

If I needed a IIC mouse, I'd just modify a mouse and see if there were
any problems.  If it was 15 years ago, I probably would have tried
it on a stray mouse that I got cheap, like I did with that Mac experiment,
but now it might be easiest to use the Mac mouse, especially in case
the IIC really needs the comparators.

  Michael