13 Nov
1998
13 Nov
'98
9:47 a.m.
Several times in the past I've seen home-brewed and
perhaps
CPU-driven signs that consist of a single vertical line of
perhaps a dozen or two LEDs.
The "sign" doesn't appear to be anything but a line of glowing LEDs.
Only when you view it at a glance, as your vision moves quickly
from side-to-side, do you see that it is rapidly flickering the
?vertical scanlines
of a simple dot-matrix image: maybe the digits
of the time, perhaps a smiley face, or some other
simple image.
I don't know the name of it... but I remember that there was some
sort of a contest a few years ago... Contestants were provided a
number of items and had to build a display. The winning design
had some sort of saw-blade which was moved by use of an
electromagnet. The vertical set of LEDs would display the
lines which comprised a character, and the saw-blade was moved
back and forth in synch in such a way that when vieing the
reflection of the LEDs in the shiny surface of the moving
blade, one could make out characters.
Megan Gentry
Former RT-11 Developer
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| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
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