13 Apr
2001
13 Apr
'01
3:18 a.m.
If you can scrounge the key switches and caps you need from an extra
PC-keyboard, that's great! As for the displays, I'd suggest you either (1) wire
the displays in parallel with what's already there, or (2) fabricate a duplicate
driver circuit, with both the encoders (or segment drivers) and the digit
selects (I haven't yet looked at the schematic to see what's easiest) as well as
the current-limiting resistors. The latter will provide more satisfying
results, methinks. I'd recommend LARGE displays and a convenient keypad layout.
The reason will become obvious as you get older.
Dick
----- Original Message -----
From: "Ross Archer" <dogbert(a)mindless.com>
To: <classiccmp(a)classiccmp.org>
Sent: Friday, April 13, 2001 7:17 AM
Subject: Re: Kim / Commie keypads
----- Original Message -----
From: Richard Erlacher <edick(a)idcomm.com>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, April 11, 2001 11:41 AM
Subject: Re: Kim / Commie keypads
Yes ... cannibalizing a PC keyboard might be a
solution, provided you can
come
up with a way to modify the keycap legends.
Or not.
0-9 ==> 0-9 (from top row)
A-F ==> A-F
AD ==> * (from numeric keypad)
DA ==> Insert (from stand-alone pad)
PC ==> P
+ ==> +/= (or + on numeric if not oversize cap)
GO ==> G
ST ==> S
RS ==> R
Of course, you could duplicate the layout exactly.
:)
Thanks for the ideas again. This ought to work relatively
well.
The outboard display is mostly no-go though.
Although the 7-segment digital lines go out to
the application connector, where they can be
re-buffered with a 74HC06 or similar, the lines
to select which LED to light at any particular scan
moment (nor the raw undecoded input selecting them)
do not leave the board. I'd have to solder to something,
whether it was the 6530 or the decoder. For obvious
reasons, if I did solder to it, it would be on the decoder
outputs x 6, since I can get another one of those if they fried. :)
MicroSwitch once made keyboard
switches that had an undersized keycap with a clear plastic cover that was
"normal" sized. You could put a paper legend underneath the clear cover,
obviously, and thereby avoid having to replace it all the time, not that
replacing it would be a big chore.
Dick
----- Original Message -----
From: "Sellam Ismail" <foo(a)siconic.com>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, April 11, 2001 1:12 AM
Subject: Re: Kim / Commie keypads
> On Wed, 11 Apr 2001, Ross Archer wrote:
>
> > But still I would like a "nice looking"
> > keypad, or at least "not amateurish".
> > So does anyone know where one might find
> > a "take a bunch of keycaps and fit into a plastic
> > grid to make your own keypad array" sort of kit?
>
> Maybe you can find an old calculator with a suitable keypad and
> cannibalize it? Or perhaps some old PC numeric keypad?
>
> Sellam Ismail Vintage Computer
Festival
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