There have been many different designs for piano roll scanners but
none seem to easy to build or to duplicate. I've also noticed flaws,
the main one being that the scanner typically works like a normal
player piano spool box and just winds the roll up as it scans. That
makes the take-up spool acceleration a problem.

I had an idea to take that design and make it a bit more precise,
accurate, and also to make it easier to build. I was thinking that you
could take the CIS scanner bar and lay it flat on its face over the
roll. The scanner wouldn't be a vertical type; it would be a flat-bed
scanner of sorts.

The roll would be pulled under the scanner bar by means of a printer
advancement wheel (the small metal bar with rubber cylinders that
pushes the paper through inkjet printers). The take-up spool would
have a constant but very light tension on it. This way the roll would
be advanced, say, one-sixteenth of an inch or less with every step,
and the take-up spool would simply pull up the slack.

The reason why the printer advancement shaft would be useful is because
it moves the paper a specific distance every time. It is not affected
by take-up spool acceleration making the scans more even and accurate.

Another plus to this design is that the scanner in general is more
gentle to the paper, the step size can be set to the perforator pitch
at which the roll was punched, and the scanner would be smaller and
easier to build because of the flatness of the design.

If someone did end up building a scanner in this manner, it would be
very useful to be able to scan into a PNG or JPG image as well as use
the readily available CIS software made by Warren Trachtman.

The reason I like the image files over the CIS file is because the roll
scan images could be scanned to MIDI file with PlaySK roll reader or
printed with a dot matrix printer and hand cut into new rolls.

Either way, this would be very helpful for hobbyists like myself that
don't have the time, technical know-how or the resources to build a
full-blown MK3 roll scanner or similar.

Piotr Barcz