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 [ Ref. 080210 MMDigest "New Music Roll Perforator", by Wagner Mello

Hello MMD,  I also built some perforators of this kind, and developed
the related software as well.  This software is "all in one", like Bob
Essex's system (and, by the way, is compatible with it).  Some videos
of the working machines may be seen on my web site, at the bottom of
these pages (I apologize for the language of the whole site -- French
only for the moment. ;o) :

  http://pagesperso-orange.fr/orgue-de-barbarie/perforatrice_1.htm
or
  http://pagesperso-orange.fr/orgue-de-barbarie/essais_et_performances.htm

The software includes many features like half-stepping, acceleration or
deceleration for the motors, webbing of long notes, and a very practical
recovery mode which allows to stop the job at any moment and to resume
it later on, even if the computer and the machine were switched off.

An English version is downloadable for free at this address :

  http://pagesperso-orange.fr/orgue-de-barbarie/download.htm

But it seems that some people experienced some problems with the
installation.  Contact me...

Answering to Wagner Mello, I'd say that there I don't have any magic
formula, but the starting time and ending time of each note are closer
to the nearer motor step (or more, this is a parameter).

The MIDI processing algorithm operates in two steps:

- First, it calculates the starting and ending position of each notes
in a number of what I call "punching steps".  This punching step is
user definable, and is a number of motor steps.  Therefore, if required,
the punching accuracy may be one motor step (the closer one).  And
obviously, it will have an impact on the punching duration.

- Secondly, according to the punching step and to the size of the
punch, complementary hole positions between start and end of the notes
are determined, matching a grid which starts from the beginning of the
music.  The step of this grid combined with the punch size, allows the
webbing.

The result is a working table, which is used by the main process in
order to drive the head, the punch and the paper all along the tune.
By doing it this way, the holes are all aligned by rows, excepting the
start and the end of the notes.  The whole punching is a bit longer
than with regular spacing but not so much (about 30% more).

If this can help...

Pierre Pénard
http://pagesperso-orange.fr/orgue-de-barbarie/index.htm

P.S.: Amazingly, my next project is also a piano, but it doesn't yet
play at all.  So you can't hear it while the punch machine works.  ;o)