1 Apr
2010
1 Apr
'10
11:34 a.m.
-------------Original Message:
Message: 27
Date: Thu, 1 Apr 2010 00:39:06 -0400
From: Dave McGuire <mcguire at neurotica.com>
Subject: Re: Reading ancient paper digital media (was Re: Hamurabi
Focal source)
<snip>
The way my reader (A Documation
M200) does it is to move the card at constant speed using known-diamter
rollers, then to detect the leading edge of the card (basically when the
optical sensors g form all on to all off, then use that to produce an
internal clock signal that should align with the centres of the columns
(if you see what I mean) and us that to strobe the read logic.
What if the card slips?
-Dave
--------------Reply:
Some readers used a blade that caught the edge of the card and pushed
it through just as the parallel-read IBM EAMs had done in the old days;
no problem with slippage, it either fed correctly or jammed.
mike