31 Mar
2010
31 Mar
'10
9:54 p.m.
On Thu, 1 Apr 2010, Dave McGuire wrote:
Then the far edge of the card shows up at the wrong time, and the reader
generates a fault. Use to happen (rarely) with the IBM card readers.
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?