4 Dec
2008
4 Dec
'08
12:46 p.m.
Hi Folks,
It's been interesting taking out my old CP/M stuff and getting it
operational again.
My system uses an 8bit TTL Keytronics Capacitive Sense keyboard. It was
operational for about an hour and then it quit.
It turns out that the keyboard uses little sponge pads to hold the
capacitive disks and they have biodegraded into dust.
I've seen the pads for say on Ebay. Fitting them is quite easy, and this
might be the easiest solution.
So I went looking for an old 8b TTL replacement keyboard. So far no luck.
I also looked for a black box solution that would take an AT or PS/2
keyboard and convert it to a parallel port output. So far no luck.
I beelive raeady-made products like that exist, but the one I looked at
was not cheap. It's a fairly simple task for a microcontroller, I suspect
there's at least one such project on the web, but you might not wat to
get programing and soldering.
Alternatively, it's not small, but how about using an older laptop? Write
a simple program to read characters from the keyboard and blast them out
of the parallel printer port, giving a suitable strobe pulse. You
couldn't use the normal printer driver (which would expect a handshake
from the printer), but since the port is entriely
software driven, you
can prodcue the required signals using software. That should
at least
do for testing.
-tony