I have been following the recent discussions about roll-punches and how
this is to be achieved. I build small hand-turned (monkey!) organs and
have adopted the German Raffin 20 and 32 note scales, together with a
26 note scale which has six extra holes on the existing 20 note
format.  A great variety of music on these scales is widely available
in UK and Europe.

I had planned to punch some of my own arrangements and I first built a
hand operated punch to do so which is effective but very tedious to
do.  After some experiments I used my old Amstrad 1640 PC with hard
drive running a very simple text messager; IBM Personal Editor, to
write the notation in roll form, vertically downwards.  This printed a
paper roll on a Star LC24-10 dot matrix printer.  By embedding ESC
control characters in the "text"the print columns could be
micro-adjusted for width and line spacing.  The notes were printed
using the solid block (Chr$ 219 or Alt 219) and the printer thus
produced a roll printed with solid bars where the lines of holes should
be.

(I suppose this printer could be adapted to actually punch the rolls,
but I should have to find a way to slow it right down.)

The game plan was to then put the roll through a second stage, on a
punch machine,  whereby the black bars were read by a phototransistor
which operated a punch at incremental intervals as the paper advanced,
driven by a stepper motor. Obviously, any part of the paper first went
through the reader and the punching done an inch or so ahead. The roll
could be punched column at a time or it is possible to have 20 punches
abreast; they can be staggered to avoid congestion whilst maintaining
synchronisation of the notes.  If several layers of paper are punched
together, only the top copy will have the black printing with holes
punched through. The machine could operate at a comfortably slow speed,
making sure that the punch is clear of each hole before the paper
advances.

This system entails writing the music in vertical bar format on the
screen, to do which I used the IBM PE macro ability to write each
length of note.  This was OK, but then I bought the Pentium PC with
Sound Card and MIDI, running Cakewalk pro.  MIDI appears to open a
whole new world and I have abandoned the above project for the moment.
I now need to find a MIDI decoder of the simplest kind (note-on and
note-off information only I guess) to front-end a roll punch, drive an
organ direct and even to drive my player piano.

Does anyone know of a supplier for such a device? I can handle the
electronics from the outputs, but my knowledge of UARTS etc is rusty
and I haven't the facilities to work with data at MIDI speed.

Bob Essex