24 May
2012
24 May
'12
3:19 a.m.
On Wed, 23 May 2012, Jonas Otter wrote:
Am I completely wrong if I think I remember that the
sprocket holes have
a fixed relationship to the data holes? If so, it ought to be possible
to build an optical decoder, illuminate it with a simple light bulb,
connect it to an input-capable parallel port on a computer with suitable
software, and simply pull the tape through by hand? The sprocket holes
would function as a clock for the data.
Agreed it is rather primitive, but for a one-off job of not too much tape it
could be less work than messing around with a scanner.
I have a setup that is exactly that: a gooseneck lamp glued to a board
which also contains an optical decoder with parallel output. To use it,
you point the gooseneck at the detector and manually pull the tape
through. I should pull it out sometime and photograph it for the list.
Reading paper tape with electrical contacts works only up to a certain
speed. Past that speed, the contacts tend to fly across the holes instead
of dipping into them. There is also added wear to the tape. This spurred
the development of optical readers that function preceisely as you
describe.
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?