21 May
2012
21 May
'12
11:44 a.m.
On Mon, May 21, 2012 at 2:04 PM, John Foust <jfoust at threedee.com> wrote:
At 11:28 AM 5/21/2012, Ethan Dicks wrote:
I was using an auto-feed scanner... Brother brand. To get the
contrasty background (to get the holes to show up), I loaded the punch
card into the provided envelope for scanning receipts and small items.
Without modifying my scanner, I could not get the background to be
anything but white for a naked punch card. I did not wish to hack on
the hardware, and with all the fiddling around, it took too long per
card to get scans.
Yes, it's possible to hack up some hardware that gets used just for
scanning cards. No, I didn't care to do that.
If you were
scanning a short stack of cards, it wasn't so bad, but a 3 foot deck?
You'd spend a lot of time just getting the cards in and out of the
scanner.
Well, there are many scanners that can auto-feed a half-inch-tall pile. As for paper tape, what about the super-duper overkill
of recognizing
a video stream from a web cam? ?All you'd need is a jig to slowly
pull the tape past the fixed camera.
If I wanted to read a bunch of paper tape, I'd probably build my own
scanner from 9 photodiodes from the article in Byte magazine.
http://www.classiccmp.org/cini/pdf/byte/manual_ptp.pdf
-ethan