19 Feb
2009
19 Feb
'09
3:57 p.m.
I'm aware of something close...
The HP2114 computers use a capacitive proximity switch.
There is a small variable capacitor behind the front panel to adjust the
sensitivity of the switch.
If its over-adjusted, a wave of a finger will toggle the switch register
bits, which then light up
from behind.
----- Original Message -----
From: "Mike Loewen" <mloewen at cpumagic.scol.pa.us>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Sunday, February 01, 2009 11:19 AM
Subject: Optically switched control panel?
A member of another list thinks he remembers a large computer with a
control/maintenance panel that used optical switches to set and clear
register bits. The operator would place a finger in a hole/depression,
interrupting a light beam to a photosensor, toggling a flip-flop.
Did such a system exist, or is this just wishful thinking?
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/