Reading ancient paper digital media (was Re: Hamurabi Focal source)

On 3/31/10, Tony Duell <ard at p850ug1.demon.co.uk> wrote: I did that exact thing with punched cards as an experiment. I did not (and still don't) have a punched card reader, but I have a correspondence course in "Data Processing" I picked up at a thrift store that came complete with blank coding forms and punch cards as teaching aids for the homework. I put the punchcard in a flatbed scanner with the unprinted side down (the "back" side) with a dark backing sheet to contrast the holes. I scanned it to a TIFF then converted it to a GIF and used Tom Boutell's GD library to import it into a C application that did some simple image transformations (edge detection, etc). I didn't complete the code to the point of converting spots to bits, but I did scale and locate the card in the scan area and was on the verge of writing the code to check for holes when I got distracted and set it aside. Making an 8 or 9 channel papertape reader from scratch is not an impossible exercise (witness the ancient Byte article referenced here every so often). Making a punchcard reader from scratch is a very different level of effort, so back then I figured that it'd be easier to use a flatbed scanner than try to make a 12-level reader and mechanical feed system on my own. These days, though, with inexpensive fabrication tools (access to laser cutters, home CNCs, Makerbots, etc) it might _not_ be as hard to make a punchcard reader -ethan