[getting old punched cards read]

From: Allison J Parent <allisonp_at_world.std.com>
Date: Tue Apr 21 20:33:13 1998

<> =============================================================guide rai
<> +
<> +
<> +
<> +
<> +++++++++++++++++++++++++++ <<<<<<<direction of motion (96 needed)
<> ^ +
<> | +
<> / +
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<> |=============================================================guide rai
<> ^optos to read the leading edge of the card for column clock, spacing
<> is such that each one is obscured as the column is over the column
<> leds making it self indexing. It's possible to go very fast.
<
<Now that I like!. I wonder where I can find some cheap photodiodes.
<
<What about one of the CCD (or similar) linear image sensor chips? They're
<quite cheap in surplus shops now, I think... A bit of optics to focus the
<image onto the sensor, and a bit of electronics to drive it (which is not
<that hard to design).

CCD needs a fair amount of electronics, photo transistors are cheaper and
simpler. Jade, JAMCO, JDR and BG micro list phototransistors pretty
cheap.


Allison
Received on Tue Apr 21 1998 - 20:33:13 BST