Re: Need Passport Soundchaser interface card schematics (or close-up photos)

[Michael J. Mahon <mjmahon@aol.com>]

"Michael J. Mahon" <mjmahon@aol.com> wrote:
> Ralph wrote:
>> I'm looking for information on the keyboard interface for the
> > Passport
>> SoundChaser keyboard.
>> This 49-key keyboard is in a wooden case, and photos
>>> I have the Mountain Computer Music System Cards, light pen, and now
>> the SoundChaser keyboard
>> (I'm a sucker for computer gear in oak or walnut boxes).  All I need
>> is the Apple 2 interface card,
>> which has only 5 chips onboard.
>>> If anyone has a close-up photo or other schematics, I'd appreciate
>> it!  Even a pinout of the 16-pin DIP
>> connector on the keyboard would be helpful, there aren't too many
> > ways
>> to do keyboard encoding.
>>> Alternatively, if you know someone within 100 miles of Indianapolis,
>> IN or Columbus, OH that has the interface card, please let me know.
> 
> That keyboard has velocity sensing, so each key actually breaks one
> contact, then makes another.  The interface must sense both events
> on all keys changing state.
> 
> It's mostly done in software, but it's pretty tricky.
> 
> I don't have the circuit, but the software makes its function pretty
> clear.

Sorry, I was thinking about the AlphaSyntauri keyboard--that was the one
with velocity sensing. 

-michael  -  NadaNet 3.1:  http://home.comcast.net/~mjmahon