Hello Patrice,

I read with interest you posting on MMD about your MIDI controller.  I
have done some 8051 programming in the past and had a lot of fun with
it.  What you have done sounds pretty cool!

I have a nickelodeon that I have recently restored.  It is a 1928
H.C Bay.  Actually it was originally an standard 88 note player but
about 30 years ago someone rebuilt it as a nickelodeon and didn't do
a very good job of it.  When I got it not much of the original player
mechanism wasn't left so I decided to rebuild it again as a
nickelodeon.  It has a 65 note player mechanism (Style A roll.  Anyone
have any style "A" rolls they'd like to sell???) but has all
88 keyboard pneumatics.  So, what I would like to do is set it up as a
MIDI player as well as a roll player.

I have located an appropriate MIDI controller that will drive magnets
(valves) but I have yet to find a cheap source for the valves.  I was
wondering what you used on your organ to drive the pipes.  Maybe I
could use something similar.

On your Self-Playing Trumpet:

I have an idea for your "artificial mouth".  What you first need is to
decide how many bits you want to use to control pressure.  Say if you
used 5 bits that would give you 32 pressure levels - probably enough I
would guess (If you used 8 bits that would give 256 pressure levels
which I think would be way too many.  I think you would have a hard
time telling one pressure level from the next.)

What you do is set up five electric valves.  For each of these valves
you connect up a different pressure source, either a manual valve or
better yet a pressure regulator.  For each valve the pressure is twice
the one before it.

Example:

Valve #1                Pressure = 1
Valve #2                Pressure = 2
Valve #3                Pressure = 4
Valve #4                Pressure = 8
Valve #5                Pressure = 16

What you now have is binary pressure!  With no valves on you have no
pressure (Binary 00000), with valves 1, 2, and 3 on you have almost
half pressure (binary 00111) and with all the valves on you have full
pressure (binary 11111).  Any binary combination will give an
equivalent pressure.  This is somewhat the same as how a reproducing
piano encodes expression levels.

Anyway, that's how I would do it.

Digitally yours,

Ray Finch